JP5718180B2 - Developing roller - Google Patents

Description

  The present invention relates to a developing roller (hereinafter also simply referred to as “roller”), and more particularly to a developing roller used in an image forming apparatus such as an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus.

  In recent years, with the advancement of electrophotographic technology, there has been an increasing demand for conductive members used in each electrophotographic process. In particular, the developing roller used in the developing process is required to have not only a predetermined electric resistance value but also various characteristics corresponding to the developing mechanism.

  Conventionally, as a developing method when a non-magnetic one-component developer is used as a developer (toner), toner is supplied to an image carrier such as a photosensitive drum holding an electrostatic latent image, and a latent image on the image carrier is obtained. A development method (pressure development method) is known in which a latent image is visualized by adhering toner to the toner. According to this method, since no magnetic material is required, the apparatus can be easily simplified and miniaturized, and the toner can be easily colored. In the pressure development method, development is performed by bringing a developing roller carrying toner into contact with an image carrier holding an electrostatic latent image and attaching the toner to the latent image on the image carrier. The developing roller used in this method needs to be formed of a conductive elastic body.

  FIG. 2 shows a configuration example of a developing device using a pressure developing method. In the illustrated developing device, a developing roller 10 is disposed in contact with a photosensitive drum 12 between a toner supply roller 11 for supplying toner and a photosensitive drum 12 holding an electrostatic latent image. As the developing roller 10, the photosensitive drum 12, and the toner supply roller 11 rotate in the directions of the arrows in the drawing, the toner 13 is supplied to the surface of the developing roller 10 by the toner supply roller 11. The supplied toner is adjusted to a uniform thin layer by the stratifying blade 14, and the developing roller 10 rotates in contact with the photosensitive drum 12 in this state, whereby the toner formed in the thin layer is transferred from the developing roller 10 to the photosensitive drum. The latent image is visualized by attaching to the 12 latent images. Note that reference numeral 15 in the drawing denotes a transfer portion, where a toner image is transferred to a recording medium such as paper. Reference numeral 16 denotes a cleaning unit, and toner remaining on the surface of the photosensitive drum 12 after transfer is removed by a cleaning blade 17. Reference numeral 18 denotes a charging roller that contacts the photosensitive drum 12 and charges the photosensitive drum 12.

  In this case, since the developing roller 10 must rotate while securely holding the photosensitive drum 12 in close contact, a conductive agent is usually added to the outer periphery of the shaft made of a highly conductive material such as metal. In order to obtain the desired surface roughness, conductivity, hardness, etc. as a basic structure, a structure in which an elastic layer made of conductive rubber, polymer elastomer, polymer foam, etc., to which conductivity has been imparted by The thing provided with the coating film of one layer or multiple layers is used.

  As an improved technique related to such a developing roller, for example, Patent Document 1 includes a shaft core and a resin layer provided around the shaft core, and the resin layer includes a resin component, a dye compound having a pyrazolone skeleton, and a conductive layer. A developing roller containing conductive fine particles is disclosed. In Patent Document 2, a conductive elastic layer is provided around a conductive shaft, and the outer peripheral surface is covered with a surface layer. The conductive elastic layer has at least one alkenyl group in the molecule. A polymer in which the repeating units constituting the main chain are mainly oxyalkylene units or saturated hydrocarbon units, a curing agent having at least two hydrosilyl groups in the molecule, a hydrosilylation catalyst, and a conductivity-imparting agent A developing roller is disclosed in which the surface layer is composed of a synthetic resin composition containing a charge control agent or charge control fine particles.

JP 2008-111951 A (claims, etc.) Japanese Patent Laid-Open No. 10-186836 (Claims etc.)

  Conventionally, when imparting conductivity to a polymer material such as urethane resin or rubber constituting the surface layer of a roller, it is common to blend an ionic conductive agent, conductive carbon, or metal powder. Was not enough. For example, conductive carbon has poor current durability, and it has been difficult to reduce resistance with an ionic conductive agent. In addition, the metal powder does not exhibit electrical conductivity unless added in a large amount, and if added in a large amount, the physical properties of the rubber deteriorate. Furthermore, it is technically difficult to disperse conductive carbon and metal powder in the coating material for layer formation, and it is difficult to adjust the dispersant, the disperser, the dispersion process, and the like.

  Accordingly, an object of the present invention is to provide a technique capable of solving the above-described problem and imparting conductivity to the roller without causing various problems as in the prior art. The object is to provide an excellent developing roller.

  As a result of intensive studies, the present inventors have formulated a predetermined amount of an azo metal complex in the intermediate coating layer in a developing roller having at least an elastic layer, an intermediate coating layer, and a surface coating layer on the outer periphery of the shaft. Thus, the inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention relates to a developing roller comprising a shaft, and an elastic layer, an intermediate coating layer and a surface coating layer sequentially disposed on the outer periphery of the shaft.
The intermediate coating layer contains an azo metal complex in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin component.

  According to the present invention, by adopting the above-described configuration, it is possible to impart conductivity to the roller without causing various problems as in the prior art, thereby realizing a developing roller having excellent energization durability. Became possible.

It is a longitudinal direction sectional view showing an example of a developing roller of the present invention. It is the schematic which shows one structural example of the image development apparatus using a pressure development method. (A), (b) is explanatory drawing which shows the measuring method of the resistance rise width in an Example.

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 developing roller of the present invention. As shown in the figure, the developing roller 10 of the present invention includes a shaft 1, an elastic layer 2, an intermediate coating layer 3, and a surface coating layer 4 that are sequentially disposed on the outer periphery thereof.

  In the present invention, it is important that the intermediate coating layer 3 contains the azo metal complex in an amount of 0.1 to 5 parts by mass, preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the resin component. . As a result, it has become possible to achieve conductivity imparting to a paint, which has been difficult to achieve with conventional ionic conductive agents and conductive carbon, without causing problems such as deterioration in rubber physical properties. Further, resistance control between the elastic layer / coating film of the roller becomes easy, and the chargeability of the roller surface and the attenuation behavior of the surface potential can be controlled. Furthermore, the improvement of the current-carrying durability has made it possible to improve the occurrence of image defects such as fogging, ghosting, and deterioration of gradation during durability. Furthermore, azo metal complexes can be blended into polymer materials such as urethane resins and rubbers, and are soluble in polar solvents, so that they are excellent in terms of coating.

  If the amount of the azo metal complex is less than 0.1 parts by mass, sufficient conductivity cannot be imparted. On the other hand, even if the amount added exceeds 5 parts by mass, there is no change in conductivity. . Examples of the metal of the azo metal complex include chromium, cobalt, and iron. Specific examples of the azo metal complex include azo compounds having a skeleton having a hydroxyl group, an amine group, and a carboxyl group at the ortho position of azobenzene. In the present invention, one type or two or more types of azo metal complexes can be appropriately mixed and used.

  In the developing roller of the present invention, only the point that the azo metal complex is blended in the intermediate coating layer in the above predetermined amount is important, and the intended effect of the present invention can be obtained. The specific configuration of the other rollers and the constituent materials of each layer can be appropriately selected according to a conventional method, and are not particularly limited.

  The shaft 1 is not particularly limited as long as it has good conductivity, and any one can be used. For example, a steel material such as sulfur free-cutting steel plated with nickel or zinc, A metal shaft such as a metal core made of solid metal such as iron, stainless steel, or aluminum, or a metal cylinder hollowed out inside can be used.

  The elastic layer 2 can be formed of rubber, resin, or a foam thereof according to the use of the roller. Specifically, for example, polyurethane, silicone rubber, butadiene rubber, isoprene rubber, chloroprene. Examples of the rubber composition include rubber, styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, epichlorohydrin rubber, and the like, and foams thereof.

  In the present invention, it is particularly preferable to use polyurethane foam. The raw material for forming such a polyurethane foam is not particularly limited as long as it contains a urethane bond in the resin.

  Examples of the polyol component include polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, polyester polyol obtained by condensing an acid component and a glycol component, polyester polyol obtained by ring-opening polymerization of caprolactone, polycarbonate diol, and the like. Can be used.

  Examples of polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, and methylglucotite. , Aromatic diamine, sorbitol, sucrose, phosphoric acid, etc. as starting materials, and those obtained by addition polymerization of ethylene oxide and propylene oxide. Particularly, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane. Those starting from hexanetriol are preferred. As for the ratio of ethylene oxide and propylene oxide to be added and the microstructure, the ratio of ethylene oxide is preferably 2 to 95% by mass, more preferably 5 to 90% by mass, and ethylene oxide is added to the terminal. preferable. In addition, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random.

  The molecular weight of the polyether polyol is bifunctional when water, propylene glycol, or ethylene glycol is used as a starting material, and preferably has a weight average molecular weight in the range of 300 to 6000, preferably in the range of 400 to 3000. Is more preferable. Further, when glycerin, trimethylolpropane, and hexanetriol are used as starting materials, they are trifunctional, and those having a weight average molecular weight in the range of 900 to 9000 are preferable, and those in the range of 1500 to 6000 are more preferable. Furthermore, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used.

  Polytetramethylene ether glycol can be obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight in the range of 400 to 4000, particularly in the range of 650 to 3000 are preferably used. It is also preferable to blend polytetramethylene ether glycols having different molecular weights. Furthermore, polytetramethylene ether glycol obtained by copolymerizing an alkylene oxide such as ethylene oxide or propylene oxide can also be used.

  Further, it is also preferable to use a blend of polytetramethylene ether glycol and a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide. In this case, it is preferable to use such a blend ratio so that the weight ratio is in the range of 95: 5 to 20:80, particularly 90:10 to 50:50.

  In addition to the polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, a diol such as butanediol, a polyol such as trimethylolpropane, or a derivative thereof may be used in combination.

  Moreover, as an isocyanate component which comprises a polyurethane foam, aromatic isocyanate or its derivative (s), aliphatic isocyanate or its derivative (s), alicyclic isocyanate or its derivative (s) is used. Among these, aromatic isocyanate or a derivative thereof is preferable, and tolylene diisocyanate (TDI) or a derivative thereof, diphenylmethane diisocyanate (MDI) or a derivative thereof is particularly preferably used.

  Tolylene diisocyanate or derivatives thereof include crude tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, these These are urea-modified products, burette-modified products, carbodiimide-modified products, urethane-modified products modified with polyols, and the like. As diphenylmethane diisocyanate or a derivative thereof, for example, diphenylmethane diisocyanate or a derivative thereof obtained by phosgenating diaminodiphenylmethane or a derivative thereof is used. Examples of the derivatives of diaminodiphenylmethane include polynuclear bodies, and pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, polymeric diphenylmethane diisocyanate obtained from a polynuclear body of diaminodiphenylmethane, and the like can be used. Regarding the number of functional groups of polymeric diphenylmethane diisocyanate, a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is usually used, and the average number of functional groups is preferably 2.05 to 4.00, more preferably 2. .50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates or derivatives thereof, such as urethane modified products modified with polyols, dimers formed by uretidione formation, isocyanurate modified products, carbodiimide / uretonimine modified products, allophanate modified products , Urea-modified products, burette-modified products, and the like can also be used. Also, several types of diphenylmethane diisocyanate and its derivatives can be blended and used.

  In addition, the isocyanate may be prepolymerized with a polyol in advance. As a method for this, the polyol and the isocyanate are put in a suitable container and sufficiently stirred, and 30 to 90 ° C, more preferably 40 to 70 ° C, A method of keeping the temperature for 240 hours, more preferably 24 to 72 hours can be mentioned. In this case, the ratio of the amount of polyol and isocyanate is preferably adjusted so that the isocyanate content of the resulting prepolymer is 4 to 30% by mass, more preferably 6 to 15% by mass. If the isocyanate content is less than 4% by mass, the stability of the prepolymer is impaired, and the prepolymer may be cured during storage, making it impossible to use. Further, when the isocyanate content exceeds 30% by mass, the content of isocyanate that has not been prepolymerized increases, and this polyisocyanate undergoes a prepolymerization reaction with a polyol component used in the subsequent polyurethane curing reaction. The effect of using the prepolymer method is diminished because it cures by a reaction mechanism similar to the one-shot process. In the case of using an isocyanate component in which isocyanate is prepolymerized with a polyol in advance, in addition to the above polyol component, diols such as ethylene glycol and butanediol, polyols such as trimethylolpropane and sorbitol, and derivatives thereof Can also be used.

  In polyurethane foam raw materials, in addition to these polyol component and isocyanate component, conductive agent and foaming agent (water, low-boiling substances, gas bodies, etc.), cross-linking agent, surfactant, catalyst, foam stabilizer, as desired. Etc. can be added, and it can be set as the elastic layer as desired by this.

  Examples of the ionic conductive agent include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, and octadecyltrimethylammonium. (Eg stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethylammonium perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, ethyl sulfate Ammonium salts such as salts, carboxylates and sulfonates, perchlorates, chlorates, hydrochlorides and bromates of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium and magnesium Iodates, 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 can be set as 1-20 mass parts with respect to 100 mass parts of resin components which comprise an elastic layer.

  Catalysts used for the polyurethane foam curing reaction include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine, and tetramethylhexanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, tetra Triamines such as methylguanidine, triethylenediamine, dimethylpiperazine, methylethylpiperazine, cyclic amines such as methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxy Alcohol amines such as ethyl piperazine and hydroxyethyl morpholine Ether amines such as bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl) aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimaleate And organometallic compounds such as dioctyltin marker peptide, dioctyltin thiocarboxylate, phenylmercury propionate and lead octenoate. These catalysts may be used alone or in combination of two or more.

  In the present invention, it is preferable to blend a silicone foam stabilizer and various surfactants during blending of the polyurethane foam in order to stabilize the cells of the foam material. As the silicone foam stabilizer, a dimethylpolysiloxane-polyoxyalkylene copolymer or the like is suitably used, and those composed of a dimethylpolysiloxane moiety having a molecular weight of 350 to 15000 and a polyoxyalkylene moiety having a molecular weight of 200 to 4000 are particularly preferable. . The molecular structure of the polyoxyalkylene moiety is preferably an addition polymer of ethylene oxide or a co-addition polymer of ethylene oxide and propylene oxide, and its molecular terminal is preferably ethylene oxide. Examples of the surfactant include cationic surfactants, anionic surfactants, ionic surfactants such as amphoteric, nonionic surfactants such as various polyethers and various polyesters. These may be used alone or in combination of two or more. The blending amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by mass, and 0.5 to 5 parts by mass with respect to 100 parts by mass of the total amount of the polyol component and the isocyanate component. More preferably.

  As a foaming method of the polyurethane foam raw material in the present invention, conventionally used methods such as a mechanical froth method, a water foaming method, and a foaming agent froth method can be used. In particular, while mixing an inert gas. It is preferable to use a mechanical floss method in which foaming is performed by mechanical stirring. Here, the inert gas used in the mechanical froth method may be an inert gas in the polyurethane reaction, and in addition to inert gases in a narrow sense such as helium, argon, xenon, radon, krypton, nitrogen, carbon dioxide, drying The gas which does not react with urethane foam raw materials, such as air, is mentioned. In the present invention, the molding conditions for the elastic layer made of such polyurethane foam raw material are not particularly limited, and may be according to ordinary conditions.

  The surface coating layer 4 is provided to adjust the physical properties of the roller, and can be formed by various solvent-based paints such as urethane, acrylic, acrylurethane, fluorine, urethane, acrylic, silica, etc. The surface roughness can be adjusted by containing fine particles comprising A conductive agent, a vulcanizing agent, a vulcanization accelerator, an antiaging agent, and the like can be appropriately added to the surface coating layer 4. The surface coating layer 4 is coated with a predetermined solvent-based paint on the intermediate coating layer 3 using a known method such as dip coating, spray coating, roll coater coating, etc., dried, and as desired. It can be formed by heat curing.

  The intermediate coating layer 3 is provided in order to improve adhesion between the elastic layer 2 and the surface coating layer 4 and resistance stability. Similarly to the surface coating layer 4, the intermediate coating layer 3 can be formed of various solvent-based paints such as urethane, acrylic, acrylic urethane, and fluorine. Moreover, about the intermediate | middle coating-film layer 3, although it is necessary to mix | blend the said azo type metal complex, by adding suitably the ionic conductive agent mentioned above and an electronic conductive agent as a electrically conductive agent, desired electroconductivity is obtained. A vulcanizing agent, a vulcanization accelerator, an anti-aging agent, and the like can be appropriately added as desired. The intermediate coating layer 3 is coated with a predetermined solvent-based paint on the elastic layer 2 using a known method such as dip coating, spray coating, roll coater coating, etc., dried, and heat-cured as desired. By forming, it is possible to form.

  In the present invention, the thickness of the elastic layer 2 is not particularly limited, but can usually be in the range of 1 to 8 mm. Moreover, the thickness of the surface layer coating-film layer 4 can be normally made into the range of 5-50 micrometers. Furthermore, the thickness of the intermediate coating film layer 3 can usually be in the range of 5 to 200 μm. In addition, as surface roughness of a surface layer coating-film layer, it is JIS arithmetic average roughness Ra, and can usually be in the range of 2 micrometers or less, especially 0.5-1.5 micrometers.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Preparation of coating film>
100 parts by mass of infinite chain length urethane prepolymer, 15 parts by mass of isocyanurated HDI, conductive agent shown in the following table, and 300 parts by mass of methyl ethyl ketone (MEK) A paint was prepared. This was poured into a 150 × 80 mm tray, dried for 1 day, and thermally cured at 120 ° C. for 1 hour to produce a sheet having a thickness of 0.2 mm. The results of measuring the volume resistivity and the resistance increase width of this coating film are also shown in the following table.

The resistance increase width was measured as shown in FIGS. 3A and 3B in an environment of 23 ° C. and 55% RH using a resistance measuring machine R8340 manufactured by ADVANTEST. That is, the roller 10 is placed on the metal plate 21 as shown in FIG. 5A, a load of 500 g is applied to both ends, and 100 V is applied between the metal shaft 1 and the metal plate 21. The resistance R _{t = 5} after 5 seconds and the resistance R _{t = 600} after 2 seconds were measured by the resistance measuring device 22. Further, the sheet 20 is placed on a metal plate 21 as shown in FIG. 5B, and a 500 g metal weight 23 is placed thereon, and the metal plate 21 and the metal weight 23 are placed on each other. and applying a 100V between, and the resistor _{R t = 5} and the resistor _{R t = 600} after 600 seconds after 5 seconds was measured by the resistance measuring device 22. From these results, the resistance width was calculated based on the following formula.
Resistance change (resistance width) log Ω · cm = log (R _{t = 600} −R _{t = 5} )

＊１）オリエント化学工業（株）製， ＶＡＬＩＦＡＳＴ ＢＬＡＣＫ ３８１７（ソルベントブラック２９ スルホン酸基 Ｃｒが配位）
＊２）オリエント化学工業（株）製， ＢＯＮＴＲＯＮ Ｓ−４４Ｓ（主成分：ソルベントバイオレット２１，ビス［１−（５−クロロ−２−ヒドロキシフェニルアゾ）−２−ナフトラト）クロム（ＩＩＩ）酸）
＊３）オリエント化学工業（株）製，ＢＯＮＴＲＯＮ Ｓ−３４（主成分：ソルベントバイオレット２１，ビス［１−（５−クロロ−２−ヒドロキシフェニルアゾ）−２−ナフトラト）クロム（ＩＩＩ）酸）
＊４）オリエント化学工業（株）製，ＳＯＭ−１−０３０７（鉄錯体＋アミンオニウム塩）
＊５）オリエント化学工業（株）製， ＢＯＮＴＲＯＮ Ｐ−５１（ベンジルトリブチルアンモニウム−４−ヒドロキシナフタレン−１−スルフォネート）
＊６）オリエント化学工業（株）製，ＶＡＬＩＦＡＳＴ ＢＬＡＣＫ １８０７（Ｃ．Ｉ．Ａｃｉｄ ブラック５２）

＊７）日本カーリット（株）製，ＰＥＬ４６
＊８）自社製

* 1) Orient Chemical Industry Co., Ltd., VALIFAST BLACK 3817 (solvent black 29 sulfonic acid group Cr is coordinated)
* 2) manufactured by Orient Chemical Industry Co., Ltd., BONTRON S-44S (main component: solvent violet 21, bis [1- (5-chloro-2-hydroxyphenylazo) -2-naphtholato) chromium (III) acid)
* 3) manufactured by Orient Chemical Industry Co., Ltd., BONTRON S-34 (main component: solvent violet 21, bis [1- (5-chloro-2-hydroxyphenylazo) -2-naphtholato) chromium (III) acid)
* 4) SOM-1-0307 (iron complex + amine onium salt), manufactured by Orient Chemical Industry Co., Ltd.
* 5) manufactured by Orient Chemical Industry Co., Ltd., BONTRON P-51 (benzyltributylammonium-4-hydroxynaphthalene-1-sulfonate)
* 6) VALIFAST BLACK 1807 (CI Acid Black 52) manufactured by Orient Chemical Co., Ltd.

* 7) Nippon Carlit Co., Ltd., PEL46
* 8) Made in-house

  As shown in the above table, it was confirmed that the coating film resistance can be controlled well and the increase in resistance can be suppressed by containing the azo metal complex in the coating material.

<Production of roller>
A developing roller having an elastic layer, an intermediate coating layer and a surface coating layer sequentially supported on the outer periphery of a shaft (metal shaft) as shown in FIG.
10 parts by mass of an ether polyol (Asahi Glass Co., Ltd., EL430), 12 parts by mass of an ester polyol (Kuraray Co., Ltd., F510), and 3 parts of a foam stabilizer (manufactured by Toray Dow Corning Co., Ltd., SF2937F) Part, a polyol component containing 0.05 part by mass of a catalyst (manufactured by Nitto Kasei Co., Ltd., U-100) and 1 part by mass of KS48 (manufactured by Kao Corporation, aliphatic quaternary ammonium sulfate), and An isocyanate component in which 100 parts by mass of prepolymerized TDI (manufactured by Asahi Glass Co., Ltd., prototype) and 2 parts by mass of Denka Black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were mixed and foamed by a mechanical floss method. Then, it was poured into a mold on which a metal shaft was set. Thereafter, this mixture was heated and cured at 120 ° C. for 40 minutes to form an elastic layer having a thickness of 6 mm on the outer periphery of the metal shaft.

  Next, 100 parts by mass of an infinite chain length urethane prepolymer, 15 parts by mass of isocyanurated HDI, 3 parts by mass of a conductive agent shown in the following table, and 300 parts by mass of MEK are blended, and an intermediate coating layer A paint for was prepared. This paint was applied on the elastic layer by dipping, dried at room temperature for 30 minutes, and then thermally cured at 110 ° C. for 1 hour to form an intermediate coating layer having a thickness of 25 μm.

Next, 100 parts by mass of polytetramethylene glycol, 45 parts by mass of isocyanurated HDI, 25 parts by mass of acrylic particles (MBX-8, manufactured by Sekisui Plastics Co., Ltd.), silica (SS20, Tosoh Silica) Co., Ltd.) 25 parts by mass, 15 parts by mass of MEK dispersion (20% concentration) of Denka Black (manufactured by Denki Kagaku Kogyo Co., Ltd.), and 300 parts by mass of MEK are blended to obtain a coating layer for the surface layer. A paint was prepared. This paint was applied onto the intermediate coating layer by dipping and dried at 105 ° C. for 120 minutes to form a surface coating layer having a thickness of 20 μm.
The results of measuring the volume resistivity and resistance increase width of the obtained developing roller are also shown in the following table.

＊９）電気化学工業（株）製
＊１０）花王（株）製，脂肪族第四級アンモニウムサルフェート

* 9) Denki Kagaku Kogyo Co., Ltd. * 10) Kao Co., Ltd., aliphatic quaternary ammonium sulfate

  As shown in the above table, it was confirmed that by containing an azo metal complex in the intermediate coating layer, the resistance of the roller can be controlled well and an increase in resistance during energization durability can be suppressed.

DESCRIPTION OF SYMBOLS 1 Shaft 2 Elastic layer 3 Intermediate coating layer 4 Surface coating layer 10 Developing roller 20 Sheet 21 Metal plate 22 Resistance measuring machine 23 Metal weight

Claims (1)

In a developing roller comprising a shaft, and an elastic layer, an intermediate coating layer and a surface coating layer sequentially disposed on the outer periphery of the shaft,
The developing roller characterized in that the intermediate coating layer contains 0.1 to 5 parts by mass of an azo metal complex with respect to 100 parts by mass of the resin component.

Images