JP2020003599A - Developing roller, developing device, and image forming apparatus - Google Patents

Abstract

To provide a developing roller that satisfactorily prevents the occurrence of filming and is excellent in durable printing performance, a developing device, and an image forming apparatus.SOLUTION: A developing roller 1 comprises: an elastic layer 2 formed on an outer peripheral surface of a shaft body 2; and a coating layer 4 formed on an outer peripheral surface of the elastic layer 2. The coating layer 4 is formed by heating and curing a composition containing (a) polyol, (b) isocyanate, (c) a (meth)acrylate copolymer containing a hydroxyl group and fluorine atoms in an amount of 1 mass% or more and 10 mass% or less, (d) a surface roughness agent, and (e) an ion conductive material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a developing roller, a developing device, and an image forming apparatus.

  A developing roller used in an image forming apparatus such as a copying machine, a printer, and a facsimile that employs an electrophotographic method has a function of transporting a developer to an image carrier on which an electrostatic latent image is formed. The developer transportability of the developing roller affects the quality of the image forming apparatus, particularly, the print density. Therefore, it has been studied to form irregularities on the surface of the developing roller and to adjust the electrical characteristics of various materials constituting the developing roller, thereby improving the developer transportability of the developing roller.

  Here, when the developing roller has been used for a long period of time, the developer may adhere to the surface thereof (referred to as “filming”). Such filming is, for example, when the developer is charged or adhered, the developer is deformed or broken by a sliding stress of a blade or the like that comes into pressure contact with the developing roller, and further, development by frictional heat with the blade or the like is performed. It is thought to be caused by melting of the agent. There is a demand for a developing roller that minimizes the occurrence of filming in the developing roller and thereby stabilizes the durable printing performance.

  For example, Patent Literature 1 describes a conductive roller containing an ionic liquid, in which a developer hardly adheres to a surface for a long time. Patent Document 2 discloses a reactive fluorine-containing copolymer useful as a surface modifier for imparting anti-fingerprint property and surface smoothness to the surface of a resin, a film, a fiber, or the like.

JP 2011-221442 A JP 2015-120852 A

However, the developing roller described in Patent Document 1 cannot suppress the occurrence of filming to an extent that can sufficiently cope with the performance of an image forming apparatus required in recent years, and is not satisfactory in durability printing performance.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a developing roller, a developing device, and an image forming apparatus in which occurrence of filming is satisfactorily suppressed and excellent in durability printing performance.

  The present inventors have conducted intensive studies and found that when a specific acrylate copolymer was contained in the urethane resin adjustment component of the coating layer of the developing roller, a coating layer excellent in suppressing filming was obtained. Thus, the present invention has been completed.

  That is, the present invention is a developing roller including an elastic layer formed on an outer peripheral surface of a shaft body and a coating layer formed on an outer peripheral surface of the elastic layer, wherein the coating layer comprises (a) a polyol, (b) A) isocyanate, (c) a (meth) acrylate copolymer containing hydroxyl groups and 1% by mass to 10% by mass of fluorine atoms, (d) a surface roughness material, and (e) a composition containing an ionic conductive material. It is a developing roller formed by heating and curing an object.

  (B) The number of isocyanate groups in one molecule of isocyanate preferably exceeds 2.

  The hexadecane contact angle of the coating layer is preferably 45 ° or more and 80 ° or less.

  The developing device of the present invention includes the developing roller of the present invention.

  An image forming apparatus according to the present invention includes the developing roller according to the present invention.

  According to the present invention, it is possible to obtain a developing roller, a developing device, and an image forming apparatus in which the occurrence of filming is satisfactorily suppressed and the printing performance is excellent.

FIG. 1 is a schematic perspective view showing an embodiment of the developing roller of the present invention. FIG. 2 is a schematic sectional view showing an embodiment of the image forming apparatus of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail. However, the following embodiments are presented for the purpose of illustration, and the present invention is not limited to the embodiments described below.

[Developing roller]
FIG. 1 is a schematic perspective view showing an embodiment of the developing roller of the present invention.
As shown in FIG. 1, the developing roller 1 of the present invention includes a shaft 2, an elastic layer 3 provided on the outer periphery of the shaft 2, and a coating layer 4 provided on the outer periphery of the elastic layer 3. The coating layer 4 includes (a) a polyol, (b) an isocyanate, (c) a (meth) acrylate containing a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom, (d) a surface roughness material, And (e) heat-curing the composition containing the ion conductive material.
Hereinafter, the configuration of the developing roller 1 of the present invention will be described.

(Shaft)
As the shaft 2, preferably, a shaft used for a conventionally known developing roller having conductivity can be used. The shaft body 2 is preferably made of, for example, at least one metal selected from the group consisting of iron, aluminum, stainless steel, and brass. The shaft body 2 made of such a metal is generally known as a “core”.

  The shaft body 2 may include an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft 2 may include, for example, a core made of an insulating resin, and a plating layer provided on the core. Such a shaft 2 can be obtained, for example, by plating a core made of an insulating resin to make it conductive.

  The shaft body 2 is preferably a core metal in order to obtain good conductivity.

  The shape of the shaft body 2 is preferably, for example, a rod shape, a tubular shape, or the like. The cross-sectional shape of the shaft body 2 may be, for example, a circle, an ellipse, or a non-circle such as a polygon. The outer peripheral surface of the shaft 2 may be subjected to a treatment such as a cleaning treatment, a degreasing treatment, and a primer treatment in order to improve the adhesion to the elastic layer 3.

  The length of the shaft body 2 in the axial direction is not particularly limited, and may be appropriately adjusted according to the form of the installed image forming apparatus. For example, when the print target is A4 size, the axial length of the shaft body 2 is preferably 250 mm or more and 320 mm or less, and more preferably 260 mm or more and 310 mm or less. Further, the diameter of the shaft body 2 (diameter of the circumscribed circle) is not particularly limited, and may be appropriately adjusted according to the form of the installed image forming apparatus. For example, the outer diameter (diameter of a circumscribed circle) of the shaft body 2 is preferably 4 mm or more and 14 mm or less, and more preferably 6 mm or more and 10 mm or less.

(Elastic layer)
The elastic layer 3 is formed by heating and curing the rubber composition on the outer peripheral surface of the shaft 2. The rubber composition for forming the elastic layer 3 preferably contains rubber, a conductivity-imparting agent, and, if desired, various additives.

Examples of the rubber in the rubber composition include silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, and chloroprene. Rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, fluorine rubber and the like. It is preferably silicone or silicone-modified rubber or urethane rubber. Silicone or silicone-modified rubber can reduce compression set and is excellent in flexibility under a low-temperature environment. It is particularly preferable in that it has excellent properties. Examples of the silicone rubber include crosslinked products of organopolysiloxanes such as dimethylpolysiloxane and diphenylpolysiloxane.
Examples of the silicone rubber composition include an addition-curable millable conductive silicone rubber composition and an addition-curable liquid conductive silicone rubber composition.

-Addition-curable millable conductive silicone rubber composition-
The addition-curable millable conductive silicone rubber composition contains, for example, (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C) a conductivity-imparting agent. May be.
R ¹ _n SiO _{(4-n) / 2} (1)
In the formula (1), n represents a positive number from 1.95 to 2.05. R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 12 or less, more preferably 1 or more and 8 or less.

Examples of R ¹ include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and a dodecyl group, a cycloalkyl group such as a cyclohexyl group, a vinyl group, an allyl group, a butenyl group, and a hexenyl group. And aryl groups such as alkenyl group, phenyl group and tolyl group, and aralkyl groups such as β-phenylpropyl group. R ¹ may be a group in which part or all of the hydrogen atoms of these hydrocarbon groups are substituted with a substituent. The substituent may be, for example, a halogen atom, a cyano group, or the like. Examples of the hydrocarbon group having a substituent include a chloromethyl group, a trifluoropropyl group, and a cyanoethyl group.

  (A) The organopolysiloxane has a molecular chain terminal such as a trialkylsilyl group such as a trimethylsilyl group, a dialkylaralkylsilyl group such as a dimethylvinylsilyl group, a dialkylhydroxysilyl group such as a dimethylhydroxysilyl group, and a trivinylsilyl group. It is preferably blocked with a triaralkylsilyl group or the like.

(A) The organopolysiloxane preferably has two or more alkenyl groups in the molecule. (A) The organopolysiloxane preferably has 0.001 mol% to 5 mol% (more preferably 0.01 mol% to 0.5 mol%) of the alkenyl group in R ¹ . As the alkenyl group contained in the organopolysiloxane (A), a vinyl group is particularly preferred.

  (A) The organopolysiloxane is obtained by, for example, cohydrolytic condensation of one or more organohalosilanes, or ring-opening polymerization of a cyclic polysiloxane such as a trimer or tetramer of a siloxane. Can be obtained by: (A) The organopolysiloxane may be basically a linear diorganopolysiloxane, and may be partially branched. Further, the organopolysiloxane (A) may be a mixture of two or more kinds having different molecular structures.

  (A) The organopolysiloxane preferably has a kinematic viscosity at 25 ° C. of at least 100 cSt, more preferably at least 100,000 cSt and at most 100,000,000 cSt. Further, the polymerization degree of the organopolysiloxane (A) is, for example, preferably 100 cSt or more, and more preferably 3000 cSt or more and 10,000 cSt or less.

  Examples of the filler (B) include silica-based fillers. Examples of the silica-based filler include fumed silica and precipitated silica.

As the silica-based filler, a surface-treated silica-based filler surface-treated with a silane coupling agent represented by R ² Si (OR ³ ) ₃ can be suitably used. Here, R ² may be a group having a vinyl group or an amino group, for example, a glycidyl group, a vinyl group, an aminopropyl group, a methacryloxy group, an N-phenylaminopropyl group, a mercapto group, or the like. R ³ may be an alkyl group, for example, a methyl group, an ethyl group, or the like. The silane coupling agent can be easily obtained, for example, under the trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. The surface-treated silica-based filler can be obtained by treating the surface of the silica-based filler with a silane coupling agent according to a standard method. Commercially available products may be used as the surface-treated silica-based filler. M. A brand name “Zeothix 95” manufactured by HUBER Inc. is exemplified.

  The amount of the silica-based filler is preferably from 11 to 39 parts by mass, more preferably from 15 to 35 parts by mass, per 100 parts by mass of the organopolysiloxane (A). The average particle size of the silica-based filler is preferably 1 μm or more and 80 μm or less, more preferably 2 μm or more and 40 μm or less. The average particle diameter of the silica-based filler can be measured as a median diameter using a particle size distribution measuring device based on a laser light diffraction method.

  The compounding amount of the (C) conductivity-imparting agent is preferably at least 0.5 part by mass, more preferably at least 1 part by mass, per 100 parts by mass of the organopolysiloxane (A). Further, the compounding amount of the (C) conductivity imparting agent is preferably 15 parts by mass or less, more preferably 10 parts by mass or less based on 100 parts by mass of the organopolysiloxane (A).

  The addition-curable millable conductive silicone rubber composition may further contain additives other than (A) to (C). Examples of additives include auxiliaries (chain extenders, crosslinking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, Examples thereof include an emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, and a solvent.

  Specific examples of the additives include (A) silanol groups at both ends such as dimethylsiloxane oil, polyether-modified silicone oil, silanol, diphenylsilanediol and α, ω-dimethylsiloxanediol having a lower polymerization degree than organopolysiloxane. Dispersants such as low molecular siloxane and silane are exemplified. Further, specific examples of the additive include a heat resistance improver such as iron octylate, iron oxide, and cerium oxide. Further, as the additive, various carbon functional silanes, various olefin-based elastomers, and the like for improving adhesiveness, moldability, and the like may be used.

-Addition-curable liquid conductive silicone rubber composition-
The addition-curable liquid conductive silicone rubber composition includes, for example, (D) an organopolysiloxane having two or more alkenyl groups in a molecule, and (E) two or more hydrogen atoms bonded to a silicon atom in the molecule. And (F) a filler, (G) a conductivity-imparting agent, and (H) an addition reaction catalyst.

As the organopolysiloxane (D), a compound represented by the following average composition formula (2) is preferable.
^{_{R 4 a SiO (4-a}} ) / 2 ... (2)
In the formula (2), a represents a positive number of 1.5 or more and 2.8 or less, preferably 1.8 or more and 2.5 or less, more preferably 1.95 or more and 2.05 or less. R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. However, at least two of R ^{4 in} one molecule are alkenyl groups. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 12 or less, more preferably 1 or more and 8 or less.

As R ⁴ , the same groups as those exemplified above for R ¹ can be exemplified. Further, it is preferable that at least two of R ^{4 in} one molecule are alkenyl groups, and the other R ⁴ is an alkyl group. The alkenyl group is preferably a vinyl group, and the alkyl group is preferably a methyl group. Further, for example, 90% or more of R ⁴ may be an alkyl group (preferably a methyl group). (D) The content of the alkenyl groups in the organopolysiloxane, for example, is preferably not more than 1.0 × ¹⁰ -6 mol / g or more ^{5.0 × 10 -3 mol / g,} 5.0 × 10 - More preferably, it is ⁶ mol / g or more and 1.0 × 10 ⁻³ mol / g or less.

  (D) The organopolysiloxane is preferably liquid at 25 ° C., and the viscosity at 25 ° C. is preferably from 100 mPa · s to 1,000,000 mPa · s, more preferably from 200 mPa · s to 100,000 mPa · s. preferable. The average degree of polymerization of the organopolysiloxane (D) is preferably from 100 to 800, more preferably from 150 to 600.

As the organohydrogenpolysiloxane (E), a compound represented by the following average composition formula (3) is preferable.
^{_{R 5 b H c SiO (4}} -b-c) / 2 ... (3)
In the formula (3), b represents a positive number of 0.7 or more and 2.1 or less, c represents a positive number of 0.001 or more and 1.0 or less, and bc is 0.8 or more and 3.0 or less. It is. R ⁵ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. The number of carbon atoms in the hydrocarbon group is preferably 1 or more and 10 or less. As the R ^5, the same groups as in the above R ¹ may be exemplified.

  (E) The organohydrogenpolysiloxane has two or more hydrogen atoms (Si-H) bonded to a silicon atom in one molecule, and preferably has three or more hydrogen atoms. Also, the number of hydrogen atoms bonded to silicon atoms in one molecule of the organohydrogenpolysiloxane (E) is preferably 200 or less, more preferably 100 or less.

  (E) In the organohydrogenpolysiloxane, the content of hydrogen atoms bonded to silicon atoms is preferably from 0.001 mol / g to 0.017 mol / g, more preferably from 0.002 mol / g to 0.015 mol / g. g is more preferable.

(E) The organohydrogenpolysiloxane includes, for example, methylhydrogenpolysiloxane having a trimethylsiloxy group at both ends, a dimethylsiloxane / methylhydrogensiloxane copolymer having a trimethylsiloxy group at both ends, and a dimethylhydrogensiloxy group having both ends. Dimethylpolysiloxane, dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer at both ends, trimethylsiloxy group-blocked methylhydrogensiloxane at both ends diphenylsiloxane-dimethylsiloxane _copolymers, copolymers consisting of _(CH 3) 2 _{HSiO 1/2} units and _{SiO 4/2} units, and, CH _{3) 2} HSiO _1/2 units and _{SiO 4/2} units and _{(C 6} H ₅₎ consisting of _{SiO 3/2} units, copolymers composed, and the like.

  The compounding amount of (E) the organohydrogenpolysiloxane is preferably from 0.1 to 30 parts by mass, and more preferably from 0.3 to 20 parts by mass based on 100 parts by mass of the organopolysiloxane (D). It is more preferred that: Further, the molar ratio of Si—H of the organohydrogenpolysiloxane (E) to the alkenyl group of the organopolysiloxane (D) is preferably from 0.3 to 5.0, and more preferably from 0.5 to 2.5. Is more preferable.

  (F) The filler may be, for example, an inorganic filler. By blending the (F) filler into the addition-curable liquid conductive silicone rubber composition, the compression set is reduced, the volume resistivity is stabilized with time, and sufficient roller durability is obtained.

  (F) The filler preferably has an average particle size of 1 μm or more and 30 μm or less, more preferably 2 μm or more and 20 μm or less. (F) When the average particle diameter of the filler is 1 μm or more, the change with time of the volume resistivity is further suppressed. When the average particle diameter of the filler (F) is 30 μm or less, the elastic layer 3 having more excellent durability can be obtained. The average particle diameter of the filler (F) can be measured as a median diameter by using a particle size distribution measuring device by a laser light diffraction method.

(F) the bulk density of the filler is preferably at 0.1 g / cm ³ or more 0.5 g / cm ³ or less, and more preferably less 0.15 g / cm ³ or more 0.45 g / cm ³ . (F) By adjusting the bulk density of the filler within the above range, the compression set can be further reduced, the change with time of the volume resistivity is further suppressed, and the elastic layer 3 which is more excellent in durability. Can be obtained. (F) The bulk density of the filler can be determined based on the apparent specific gravity measuring method of JIS K 6223.

  (F) Examples of the filler include diatomaceous earth, perlite, mica, calcium carbonate, glass flake, and a hollow filler. Among them, as the filler (F), diatomaceous earth, pearlite, and pulverized pearlite can be suitably used.

  (F) The compounding amount of the filler is preferably from 5 parts by mass to 100 parts by mass, more preferably from 10 parts by mass to 80 parts by mass, based on 100 parts by mass of the organopolysiloxane (D). .

  (G) The compounding amount of the conductivity-imparting agent is preferably from 0.5 to 15 parts by mass, and more preferably from 1 to 10 parts by mass, per 100 parts by mass of the organopolysiloxane (D). More preferably, there is.

  (H) The addition reaction catalyst may be any catalyst capable of activating the addition reaction between (D) the organopolysiloxane and (E) the organohydrogenpolysiloxane. (H) Examples of the addition reaction catalyst include a catalyst having a platinum group element. Examples of the catalyst having a platinum group element include a platinum-based catalyst (for example, platinum black, platinum chloride, chloroplatinic acid, a reaction product of chloroplatinic acid with a monohydric alcohol, a complex of chloroplatinic acid with an olefin) , Platinum bisacetoacetate), a palladium-based catalyst, a rhodium-based catalyst, and the like.

  (H) The amount of the addition reaction catalyst may be a catalytic amount. For example, the compounding amount of the (H) addition reaction catalyst is such that the platinum group element content is 0.5 mass ppm or more and 1000 mass ppm or less based on the total mass of the (D) organopolysiloxane and the (E) organohydrogenpolysiloxane. Is preferable, and the amount is more preferably 1 mass ppm or more and 500 mass ppm or less.

  The elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by performing heat curing and molding simultaneously or continuously by a known molding method. The method for curing the rubber composition may be any method that can apply heat required for curing the rubber composition, and the method for forming the elastic layer 3 is also particularly limited, such as continuous vulcanization by extrusion, molding by pressing, and injection. It is not done. For example, when the rubber composition is an addition-curable millable conductive silicone rubber composition, for example, extrusion molding or the like can be selected, and the rubber composition is an addition-curable liquid conductive silicone rubber composition. In this case, for example, a molding method using a mold can be selected.

  The heating temperature for curing the rubber composition is preferably 100 ° C. or more and 500 ° C. or less, and more preferably 120 ° C. or more and 300 ° C. or less in the case of the addition-curable millable conductive silicone rubber composition. The heating time is preferably from several seconds to 1 hour, more preferably from 10 seconds to 35 minutes. In the case of an addition-curable liquid conductive silicone rubber composition, the heating temperature is preferably from 100 ° C to 300 ° C, more preferably from 110 ° C to 200 ° C. The heating time is preferably from 5 minutes to 5 hours, more preferably from 1 hour to 3 hours. Moreover, you may carry out secondary vulcanization as needed. In the case of the addition-curable millable conductive silicone rubber composition, for example, curing conditions of 100 ° C. or more and 200 ° C. or less and about 1 hour or more and 20 hours or less are selected. In addition, in the case of an addition-curable liquid conductive silicone rubber composition, for example, curing conditions of 120 ° C. or more and 250 ° C. or less and about 2 hours or more and 70 hours or less are selected. Further, by foaming and curing the rubber composition by a known method, a sponge-like elastic layer having air bubbles can be easily formed.

  The addition-curable liquid conductive silicone rubber composition may further contain additives other than (D) to (H). Examples of the additives include auxiliaries (chain extenders, crosslinking agents, etc.), foaming agents, dispersants, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, Examples thereof include a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, a diluent, a reactive diluent, and a solvent.

  Specific examples of additives include dispersants such as low molecular weight siloxane esters, polyether-modified silicone oils, silanols, and phenylsilanediol. In addition, a heat resistance improver such as iron octylate, iron oxide, and cerium oxide may be used. Further, various carbon functional silanes, various olefin-based elastomers, and the like for improving adhesiveness, moldability, and the like may be used. Further, a halogen compound or the like which imparts flame retardancy may be used.

  The viscosity of the addition-curable liquid conductive silicone rubber composition at 25 ° C. is preferably from 5 Pa · s to 500 Pa · s, more preferably from 5 Pa · s to 200 Pa · s.

  The thickness of the elastic layer 3 is not particularly limited, and is preferably 0.1 mm or more and 6 mm or less, more preferably 1 mm or more and 4 mm or less. The thickness in the present specification indicates a thickness in a direction perpendicular to the axial direction of the developing roller 1.

  The outer diameter of the elastic layer 3 is not particularly limited, and is, for example, preferably 6 mm or more and 25 mm or less, and more preferably 7 mm or more and 21 mm.

  The outer peripheral surface of the elastic layer 3 is subjected to a surface treatment such as a primer treatment, a corona treatment, a plasma treatment, an excimer treatment, a UV treatment, an itro treatment, a frame treatment and the like for the purpose of improving the adhesion to the coating layer 4 and the like. May be.

  The method for forming the elastic layer 3 is not particularly limited. For example, the elastic layer 3 may be formed by a method such as extrusion molding or LIMS molding of a silicone rubber composition. Further, the elastic layer 3 may be formed by grinding or polishing an elastic body (a cured product of the silicone rubber composition) formed on the shaft 2.

-Other components-
The rubber composition may further contain various additives other than those described above. Examples of various additives include auxiliaries (chain extenders, crosslinking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers. , An emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, a solvent and the like.

(Coating layer)
The coating layer 4 is provided on the outermost surface of the elastic layer 3 and on the outermost surface of the developing roller 1. The coating layer 4 is formed by applying a composition (hereinafter, referred to as a resin composition for a coating layer) to an outer peripheral surface of the elastic layer 3 or a primer layer formed as desired, and then coating the coating layer. The resin composition is formed by heating and curing.
The resin composition for a coating layer comprises (a) a polyol, (b) an isocyanate, (c) a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass to 10% by mass of a fluorine atom, and (d) a surface. It contains a roughness material and (e) an ion conductive material.
Hereinafter, each component (a) to (e) of the resin composition for a coating layer will be described.

(A) Polyol The polyol may be any of various polyols usually used for preparing polyurethane, and is preferably at least one polyol selected from polyether polyol, polyester polyol, polyacrylate polyol and polycarbonate polyol. .

  Polyether polyols, for example, polyethylene glycol, polypropylene glycol, polyalkylene glycols such as polypropylene glycol-ethylene glycol, polytetramethylene ether glycol, copolymer polyols of tetrahydrofuran and alkylene oxide, and various modifications thereof or these Mixtures and the like can be mentioned.

  The polyester polyol has two or more ester bonds and two or more hydroxyl groups in a molecule. Examples of the polyester polyol include a condensation product of a dicarboxylic acid and a polyol. Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid.

  Polyacrylate polyols include hydroxyl group-containing monomers and other olefinically unsaturated monomers such as esters of (meth) acrylic acid, styrene, α-methylstyrene, vinyl toluene, vinyl esters, monoalkyl maleates and dialkyl maleates. And monoalkyl fumarate and dialkyl fumarate, α-olefins and copolymers with other unsaturated oligomers and polymers.

The polycarbonate polyol has two or more carbonate bonds and two or more hydroxyl groups in a molecule. Examples of the polycarbonate polyol include a condensation reaction product of a polyol and a carbonate compound. In addition, examples of the carbonate compound include dialkyl carbonate, diaryl carbonate, and alkylene carbonate. Examples of the polyol used as a raw material of the polycarbonate polyol include diols such as hexanediol and butanediol, and triols such as 2,4-butanetriol.
The polyol preferably has a number average molecular weight of 1,000 to 8,000, more preferably has a number average molecular weight of 1,000 to 5,000 in terms of excellent compatibility with the isocyanate and the like described below, and the ionic liquid is preferably a hydroxyl group-containing ionic liquid. When it is, it preferably has a number average molecular weight of 800 to 15,000, and more preferably has a number average molecular weight of 1000 to 5000. The number average molecular weight is a molecular weight when converted into standard polystyrene by gel permeation chromatography (GPC).

(B) Isocyanate The isocyanate may be any of various isocyanates usually used for preparing polyurethane, and examples thereof include aliphatic isocyanates, aromatic isocyanates and derivatives thereof. The isocyanate is preferably an aliphatic isocyanate because storage stability is excellent and the reaction rate is easily controlled.
Examples of the aromatic isocyanate include xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (also referred to as tolylene diisocyanate; TDI), 3,3′-vitrilen-4,4′-diisocyanate, and 3,3. '-Dimethyldiphenylmethane-4,4'-diisocyanate, 2,4-tolylene diisocyanate uretidine dione (a dimer of 2,4-TDI), xylene diisocyanate, naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI), Trizine diisocyanate (TODI), metaphenylene diisocyanate and the like can be mentioned.
Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), orthotoluidine diisocyanate, lysine diisocyanate methyl ester, isophorone diisocyanate (IPDI), norbornane diisocyanate methyl, and transcyclohexane. -1,4-diisocyanate, triphenylmethane-4,4 ′, 4 ″ -triisocyanate and the like.
Derivatives include polynuclear polyisocyanates, urethane-modified products (including urethane prepolymers) modified with polyols and the like, dimers formed by uretdione formation, isocyanurate-modified products, carbodiimide-modified products, uretonimine-modified products, and allohanate-modified products. Modified urea, modified buret and the like can be mentioned. As the polyisocyanate, one type can be used alone, or two or more types can be used. The polyisocyanate preferably has a molecular weight of 500 to 2000, more preferably 700 to 1500.

The (b) isocyanate used in the resin composition for a coating layer is preferably a polyisocyanate. (B) The number of isocyanate groups in one isocyanate molecule preferably exceeds 2, more preferably 2.5 or more, even more preferably 3 or more.
Although the mixing ratio in the mixture of the polyol and the polyisocyanate is not particularly limited, the molar ratio (NCO / OH) of the hydroxyl group (OH) contained in the polyol and the isocyanate group (NCO) contained in the polyisocyanate is usually 0. It is preferably from 0.7 to 1.15. The molar ratio (NCO / OH) is more preferably 0.85 or more and 1.10 or less from the viewpoint that hydrolysis of polyurethane can be prevented. In practice, an amount equivalent to 3 to 4 times the appropriate molar ratio may be blended in consideration of working environment and working errors.

  In the resin composition for a coating layer, an auxiliary usually used for the reaction between (a) the polyol and (b) the isocyanate, for example, a chain extender, a crosslinking agent, and the like may be used in combination. Examples of the chain extender and the cross-linking agent include glycols, hexanetriol, trimethylolpropane, and amines.

(C) (Meth) acrylate copolymer containing hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atom (meth) acrylate copolymer containing hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atom The coalesced (hereinafter sometimes simply referred to as (C) (meth) acrylate copolymer) has at least a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms in the copolymer. . Such a copolymer comprises at least a fluorine-containing (meth) acrylate monomer (c-1) and a hydroxyl group-containing (meth) acrylate monomer (c-2).

  The fluorine-containing (meth) acrylate monomer (c-1) is represented by the following general formula (c-1).

In the formula, Rf is a group represented by the following formula (1) or (2). R ¹ is H or a methyl group. R ² is a divalent group having 2 to 50 carbon atoms.

Examples of the divalent group having 2 to 50 carbon atoms represented by R ² include the following groups.

_{- (CH 2) n1 - (} n1 = 2~50)
_{-X-Y- (CH 2) n2} - (n2 = 2~43)
_{-X- (CH 2) n3 - (} n3 = 1~44)
—CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n4 − (n4 = 1 to 24)
—XCO (OCH ₂ CH ₂ ) _n5 − (n5 = 1 to 21)
(Wherein X is phenylene, biphenylene or naphthylene which may have 1 to 3 substituents selected from the group consisting of alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, and halogen atoms) Y represents -O-CO-, -CO-O-, -CONH- or NHCO-.)

  X is preferably 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, and particularly preferably 1,4-phenylene.

As a particularly preferable divalent group having 2 to 50 carbon atoms represented by R ² , a divalent group having the following structure is specifically mentioned.

_{- (CH 2) n1 - (} n1 = 2~10)
—C ₆ H ₄ OCO (CH ₂ ) _n2 − (n2 = 2 to 10)
_{-C 6 H 4 (CH 2)} n3 - (n3 = 1~10)
_{-CH 2 CH 2 (OCH 2 CH} 2) n4 - (n4 = 1~10)
—C ₆ H ₄ CO (OCH ₂ CH ₂ ) _n5 − (n5 = 1 to 10)

  The (meth) acrylate compound represented by the general formula (c-1) can be produced by a known method.

  The hydroxyl group-containing (meth) acrylate monomer (c-2) is represented by the following general formula (c-2).

Wherein R ³ is H or a methyl group. R ⁴ is a divalent group having 2 to 50, preferably 2 to 10 carbon atoms, or an alkylene oxide group having 2 to 20 repeating units.

In the formula (c-2), examples of the divalent group having 2 to 50 carbon atoms represented by R ⁴ include the divalent groups exemplified for the above R ² . The divalent group preferably has 2 to 10 carbon atoms.

Is more preferably an alkylene oxide group of the repeating unit represented by R ⁴ is 2 to 20 polyalkylene oxide groups having a repeating unit of ethylene oxide group, propylene oxide group. In the polyalkylene oxide group, the repeating unit of the alkylene oxide is preferably 2 to 20.

Particularly preferred examples of R ⁴ include the following groups.

_{- (CH 2) n6 - (} n6 = 2~10)
_{- (CH 2 CH 2 O)} n7 CH 2 CH 2 - (n7 = 1~20)
_{- (CHCH 3 CH 2 O)} n8 CHCH 3 CH 2 - (n8 = 1~10)

  The compound represented by the general formula (c-2) can be produced by a known method, or can be obtained as a commercial product. Commercially available products of the compound represented by the general formula (c-2) include Blenmer AE-90 manufactured by NOF Corporation, Blenmer AE-200 manufactured by NOF Corporation, and Blemmer AE manufactured by NOF Corporation. -400, NOM Corporation's Blenmer AP-400, NOF Corporation's Blemmer PE-90, NOF Corporation's Blemmer PE-200, NOF Corporation's Blemmer PE-350 Blenmer PP-1000 manufactured by NOF CORPORATION, 50 PEP-300 manufactured by NOF CORPORATION, 70 PEP-350 manufactured by NOF CORPORATION, 55 PET-800 manufactured by NOF CORPORATION -Hydroxyethyl acrylate (Kyoeisha Chemical Co., Ltd., Light Ester HO-250), 2-hydroxyethyl acrylate (Kyoeisha Chemical Co., Ltd., Light Ester HOA), 4-hydroxybutyrate Acrylate (Osaka Organic Chemical Industry Co., Ltd., 4-HBA) and the like.

  (C) The (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom includes the above-mentioned fluorine-containing (meth) acrylate monomer (c-1) and a hydroxyl-containing (meth) acrylate In addition to the monomer (c-2), a (meth) acrylate (c-3) represented by the following general formula (c-3) can be used as a monomer that forms a structural unit of the copolymer.

Wherein R ⁵ is H or a methyl group. R ⁶ is an aromatic hydrocarbon group which may be substituted. n is an integer of 0-4.

In the general formula (c-3), examples of the aromatic hydrocarbon group represented by R ⁶ include a phenyl group, a naphthyl group, a toluyl group, a xylyl group, an anthranyl group, a phenanthryl group, and a biphenyl group. To 15 aromatic hydrocarbon groups. Examples of the substituent of the substituted aromatic hydrocarbon group include methyl, ethyl, propyl, butyl, methoxy, ethoxy, methylenedioxy, chlorine atom, NO ₂ , CN, NHCOCH _{3 and the} like. The aromatic hydrocarbon group may contain 1 to 3 substituents, preferably 1 to 2 substituents.

  Particularly preferred as the (meth) acrylate compound represented by the general formula (c-3) is benzyl methacrylate.

  The compound represented by the general formula (c-3) can be produced by a known method, or can be obtained as a commercial product.

  Further, (meth) acrylate (c-3) represented by the following general formula (c-4) can also be used as a monomer forming a structural unit of the copolymer.

Wherein R ⁷ is H or a methyl group. R ⁸ is H or an aliphatic hydrocarbon group having 1 to 50 carbon atoms.

In the general formula (c-4), R ⁸ is an aliphatic hydrocarbon group having 1 to 50 carbon atoms. The aliphatic hydrocarbon group may have an ether bond, an ester bond, an amide bond, or a cyclic structure.

Preferred examples of R ⁸ include cyclic structures such as an alkyl group, a cyclohexyl group, a dicyclopentanyl group, and a dicyclopentenyl group. Particularly preferred examples of R ⁸ include an aliphatic hydrocarbon group having the following structure.

_{- (CH 2) n6 CH 3} (n6 = 1~30)

  The compound represented by the general formula (c-4) can be produced by a known method, or can be obtained as a commercial product. As commercially available products of the compound represented by the general formula (c-4), Blemmer CHMA manufactured by NOF Corporation, Blemmer LMA manufactured by NOF Corporation, Blemmer SMA manufactured by NOF Corporation, NOF ( Co., Ltd., Blemmer VMA, NOF Corp., Blemmer CHA, NOF Corp., Blemmer LA, NOF Corp., Blemmer SA, NOF Corp., Blemmer VA, Hitachi Chemical ( FA-513AS manufactured by Hitachi Chemical Co., Ltd., and FA-513M manufactured by Hitachi Chemical Co., Ltd.

  (C) The content of the (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom in the resin composition for a coating layer includes (a) a polyol, (b) an isocyanate, And (c) It is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, based on 100 parts by mass of the (meth) acrylate copolymer in total.

(D) Surface roughness material The coating layer 4 contains a surface roughness material. The surface roughness material is a particle for adjusting the surface roughness of the coating layer 4. The average particle size of the surface roughness material blended in the coating layer 4 is preferably 0.1 μm or more and 20 μm or less, more preferably 1 μm or more and 15 μm or less. By blending such a surface roughness material in the coating layer 4, the surface roughness of the outer peripheral surface can be easily adjusted to an appropriate range. By adjusting the surface roughness of the outer peripheral surface of the developing roller 1, toner transportability is improved, and more excellent printing characteristics can be obtained. The average particle diameter of the surface roughness material can be measured as a median diameter using a particle size distribution measuring device based on a laser light diffraction method.

  The surface roughness (Rz) of the coating layer 4 is, for example, preferably from 1 μm to 20 μm, and more preferably from 1 μm to 15 μm. In this specification, the surface roughness (Rz) of the coating layer 4 indicates a ten-point average roughness measured by a method specified in JIS-1994. The surface roughness of the coating layer 4 can be easily adjusted by, for example, the type and amount of the surface roughness material to be mixed.

  The type of the surface roughness material mixed in the coating layer 4 is not particularly limited, and can be appropriately selected from known fillers (fillers). For example, silica, spherical resin particles, metal oxides and the like may be used.

  The content of the surface roughness material in the resin composition for a coating layer is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the resin composition for a coating layer. Is more preferred.

(E) Ion conductive material Examples of the ionic conductive material include sodium perchlorate, lithium perchlorate, calcium perchlorate, lithium chloride, lithium bis (trifluoromethanesulfonyl) imide, and potassium bis (trifluoromethanesulfonyl) imide. And the like. The content in the resin composition for an ionic conductive material coating layer is preferably 0.01 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the resin composition for a coating layer. Is more preferred.

  The coating layer 4 may further contain additives other than those described above. For example, the coating layer 4 may further contain additives such as a silane coupling agent, a lubricant, a polymerization catalyst, a dispersant, and a filler.

  The coating layer 4 is obtained by coating the resin composition for a coating layer on the elastic layer 3 and containing (a) a polyol component and (c) a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms by heating or the like ( The meth) acrylate copolymer component and the (b) isocyanate component are polymerized and cured. The solvent used for the coating liquid is preferably a solvent capable of dissolving the polyol component and the isocyanate component, and may be, for example, ethyl acetate, butyl acetate, or the like.

(Contact angle)
The coating layer 4 preferably has a hexadecane contact angle of 45 to 80 °, more preferably 50 to 80 °, and particularly preferably 50 to 75 °. The contact angle can be measured using, for example, a contact angle meter (trade name “CA-DT type”, manufactured by Kyowa Interface Chemical Co., Ltd.). A sample obtained by cutting out a region of the coating layer 4 that contacts the developer into a size of 10 mm × 10 mm is set in a contact angle meter, and hexadecane droplets are dropped on the sample as a test solution so that the droplet diameter becomes 2 mm. The measurement of the contact angle is obtained by reading the angle formed between the contact point of the sample and the droplet and the top of the droplet using an angle scale built in the contact angle meter and converting the angle to twice.

  When the contact angle is within the above range, the developer melted by the operation of the image forming apparatus hardly adheres to the coating layer 4, and the amount of the developer fixed to the coating layer 4 can be significantly reduced.

  The thickness of the coating layer 4 is preferably 1 μm or more and 15 μm or less, more preferably 3 μm or more and 10 μm or less from the viewpoint of improving the durability printing performance while favorably suppressing filming.

The coating of the resin composition for a coating layer may be performed, for example, by a coating method of coating a coating liquid of the resin composition for a coating layer, a dipping method of dipping the elastic layer 3 or the like in the coating liquid, or a coating liquid of an elastic layer. The coating is performed by a known coating method such as a spray coating method spraying on 3 or the like. The resin composition for a coating layer may be applied as it is, or may be applied to the resin composition for a coating layer, for example, alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, ethyl acetate and butyl acetate. A volatile solvent such as an ester-based solvent or a coating solution to which water is added may be applied. The method of curing the resin composition for a coating layer coated in this manner may be any method that can apply heat necessary for curing the resin composition for a coating layer, and for example, the resin composition for a coating layer. A method of heating the coated elastic layer 3 and the like with a heater, and the elastic layer 3 and the like coated with the resin composition for a coating layer. The heating temperature at the time of heating and curing the resin composition for a coating layer is, for example, preferably 100 ° C. or more and 200 ° C. or less, more preferably 120 ° C. or more and 160 ° C. or less, and the heating time is 10 minutes or more. It is preferably 120 minutes or less, more preferably 30 minutes or more and 60 minutes or less.
In the coating layer 4 thus formed, the precursor forming the resin and the ionic conductive material may react to form a single body, or may form a composite. Further, the ion conductive material may be dispersed in the resin without reacting with the precursor forming the resin.

(Other configurations)
The developing roller 1 of the present invention may include an intermediate layer such as an adhesive layer or a primer layer between the shaft body 2 and the elastic layer 3 and between the elastic layer 3 and the coating layer 4. Here, among these intermediate layers, in particular, for the adhesive layer and the primer layer provided between the elastic layer 3 and the coating layer 4, the electrical properties of the developing roller 1 are adjusted by adjusting the electrical properties. Can be adjusted, whereby the developing performance of the developing roller 1 can be satisfactorily adjusted.

  As the primer layer, those usually used as a primer layer of a developing roller can be used. For example, by forming a primer layer made of a urethane resin having an ester group, the developing performance of the developing roller 1 can be improved. Can be maintained.

[Developing device and image forming device]
The developing roller 1 according to this embodiment can be suitably used as a developer carrier in a developing device and an image forming apparatus. In the present embodiment, the configuration other than the developing roller 1 in the image forming apparatus is not particularly limited. An example of a developing device and an image forming apparatus provided with the developing roller 1 of the present invention will be described with reference to FIG.

  The image forming apparatus 10 is a tandem color image forming apparatus in which a plurality of image carriers 11B, 11C, 11M, and 11Y provided in developing units B, C, M, and Y of respective colors are arranged in series on a transfer / conveying belt 6. The developing units B, C, M, and Y are arranged in series on the transfer / conveyance belt 6. The developing unit B includes an image carrier 11B, for example, a photoconductor (also referred to as a photosensitive drum), a charging unit 12B, for example, a charging roller, an exposure unit 13B, a developing device 20B, and an image carrier via a transfer / conveying belt 6. A transfer unit 14B, for example, a transfer roller that contacts the body 11B, and a cleaning unit 15B are provided.

  The developing device 20B is an example of the developing device of the present invention, and includes the developing roller 1 of the present invention and a developer 22B as shown in FIG. Therefore, in the image forming apparatus 10, the developing roller 1 is mounted as the developer carrying members 23B, 23C, 23M, and 23Y, that is, the developing rollers. Specifically, the developing device 20B includes a housing 21B that accommodates the one-component non-magnetic developer 22B, a developer carrier 23B that supplies the developer 22B to the image carrier 11B, for example, the developing roller 1, and a developer. The image forming apparatus includes a toner supply roller 25B for supplying the developer 22B to the carrier 23B, and a developer amount adjusting unit 24B for adjusting the thickness of the developer 22B, for example, a blade. In the developing device 20B, the developer amount adjusting means 24B is in contact with or in pressure contact with the outer peripheral surface of the developer carrier 23B as shown in FIG. That is, the developing device 20B is a “contact type developing device”. The developing units C, M and Y have basically the same configuration as the developing unit B, and the same elements are denoted by the same reference numerals and symbols C, M or Y indicating the respective units, and description thereof will be omitted. .

  In the image forming apparatus 10, the developer carrier 23B of the developing device 20B is arranged such that the surface thereof comes into contact with or presses against the surface of the image carrier 11B. Similarly to the developing device 20B, the developing devices 20C, 20M and 20Y are arranged such that the surfaces thereof are in contact with or press-contact the surfaces of the developer carriers 23C, 23M and 23Y with the surfaces of the image carriers 11C, 11M and 11Y. . That is, the image forming apparatus 10 is a “contact type image forming apparatus”.

  The fixing unit 30 is disposed downstream of the developing unit Y. The fixing unit 30 includes a fixing roller 31, an endless belt support roller 33 disposed near the fixing roller 31, a fixing roller 31 and an endless belt, in a housing 34 having an opening 35 through which the recording medium 16 passes. The fixing roller 31 and the pressing roller 32 are provided with an endless belt 36 wound around a supporting roller 33 and a pressing roller 32 disposed opposite to the fixing roller 31. Is a pressure heat fixing device rotatably supported. At the bottom of the image forming apparatus 10, a cassette 41 for storing the recording body 16 is installed. The transfer conveyance belt 6 is wound around a plurality of support rollers 42.

  Each of the developers 22B, 22C, 22M, and 22Y used in the image forming apparatus 10 may be a dry developer or a wet developer as long as it can be charged by friction, and may be a non-magnetic developer or a magnetic developer. It may be an agent. In the housings 21B, 21C, 21M, and 21Y of the developing units B, C, M, and Y, a one-component nonmagnetic black developer 22B, a cyan developer 22C, a magenta developer 22M, and a yellow developer 22Y are provided. It is stored.

  The image forming apparatus 10 forms a color image on the recording body 16 as described below. First, in the developing unit B, an electrostatic latent image is formed by the exposure unit 13B on the surface of the image carrier 11B charged by the charging unit 12B, and a black electrostatic latent image is formed by the developer 22B supplied by the developer carrier 23B. The image is developed. Then, when the recording body 16 passes between the transfer means 14B and the image carrier 11B, the black electrostatic latent image is transferred onto the surface of the recording body 16. Next, in the same manner as the developing unit B, the cyan image, the magenta image, and the yellow image are superimposed on the recording body 16 in which the electrostatic latent image is visualized as a black image by the developing units C, M, and Y, respectively. A color image is visualized. Next, the recording medium 16 in which the color image has been visualized is fixed to the recording medium 16 as a permanent image by the fixing unit 30. Thus, a color image can be formed on the recording body 16.

  The developing device 20B includes the developing roller 1 and is excellent in developer transportability, suppresses toner filming, and can contribute to forming a high-density, high-quality image for a long period of time. Further, this image forming apparatus can form a high-density and high-quality image for a long period of time.

  The developing device and the image forming device of the present invention are not limited to those described above, and various modifications are possible within a range where the object of the present invention can be achieved.

  Although the image forming apparatus is an electrophotographic image forming apparatus, in the present invention, the image forming apparatus is not limited to the electrophotographic type, and may be, for example, an electrostatic image forming apparatus. . Further, the image forming apparatus provided with the developing roller of the present invention is not limited to a tandem-type color image forming apparatus in which a plurality of image carriers each having a developing unit of each color are arranged in series on a transfer / conveying belt. Alternatively, a monochrome image forming apparatus having a single developing unit, a four-cycle type color image forming apparatus that repeats primary transfer of a developer image carried on an image carrier sequentially to an endless belt, or the like may be used. Further, the developer used in the image forming apparatus is a one-component non-magnetic developer, but in the present invention, it may be a one-component magnetic developer or a two-component non-magnetic developer. Alternatively, a two-component magnetic developer may be used.

  The image forming apparatus is a contact-type image forming apparatus that is disposed in contact with or pressure contact with an image carrier, a developer supply roller, a blade, and the like. Note that the image forming apparatus of the present invention may be a non-contact type image forming apparatus arranged with a gap so that the surface of the developer carrier does not contact the surface of the image carrier.

  As described above, the present invention has been described using the embodiment. However, it is needless to say that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiment, and various changes or changes may be made to the above embodiment. It is clear to a person skilled in the art that improvements can be made. It is also apparent from the description of the claims that the invention with such changes or improvements can be included in the technical scope of the present invention.

  Hereinafter, the present invention will be described in detail with reference to examples. It should be noted that the present invention is not limited to the embodiments described below.

[Example 1]
(Formation of primer layer)
The shaft body (made of SUM22, diameter 10 mm, length 275 mm) subjected to electroless nickel plating is washed with ethanol, and its surface is coated with a silicone primer (trade name “Primer No. 16”, manufactured by Shin-Etsu Chemical Co., Ltd.). ) Was applied. The shaft treated with the primer was baked at 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the outer peripheral surface of the shaft.

(Formation of elastic layer)
Next, a silicone rubber composition for forming an elastic layer was prepared as follows. That is, 100 parts by mass of dimethylpolysiloxane (degree of polymerization: 300) having both ends capped with a dimethylvinylsiloxy group, and a hydrophobized fumed silica having a BET specific surface area of 110 m ² / g (trade name “R-972”) , 1 part by mass of Nippon Aerosil Co., Ltd.), 40 parts by mass of diatomaceous earth (trade name "Oprite W-3005S", manufactured by Chuo Silica Co., Ltd.) having an average particle diameter of 6 μm and a bulk density of 0.25 g / cm ³ ; , 5 parts by mass of acetylene black (trade name “DENKA BLACK HS-100”, manufactured by Denka Corporation) were put into a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This was returned to the planetary mixer again, and 2.1 parts by mass of methyl hydrogen polysiloxane having a Si—H group at both ends and side chains (polymerization degree 17, Si—H content 0.0060 mol / g), ethynylcyclohexanol 0.1 part by mass and 0.1 part by mass of a platinum catalyst (Pt concentration: 1% by mass) were added, and the mixture was stirred and defoamed and kneaded for 30 minutes to prepare an addition-curable liquid conductive silicone rubber composition.

  The prepared addition-curable liquid conductive silicone rubber composition was molded into an elastic body made of a rubber material on the outer peripheral surface of a shaft body by injection molding using a mold. In the injection molding, the addition-curable liquid conductive silicone rubber composition was cured by heating at 120 ° C. for 10 minutes, and subjected to secondary vulcanization at 200 ° C. for 4 hours to form an elastic layer having an outer diameter of 16 mm.

(Formation of coating layer)
Next, a resin composition for forming a coating layer was prepared as follows.
In the resin composition for a coating layer, (a) a total content of a polyol and (b) an isocyanate; and (c) a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass to 10% by mass of a fluorine atom. Table 1 shows the contents (parts by mass) of (d) the surface roughness material and (e) the ionic conductive material.

-Coating layer resin composition-
(A) Condensed polyester polyol (mixing molar ratio of 1,6-hexanediol and adipic acid [COOH / OH] = 12/13, and the number average molecular weight measured by the above measurement method is in the range of 1,000 to 8,000. 28 parts by mass (b) 14 parts by mass of polyisocyanate (hexamethylene diisocyanate) (c) 1 part by mass of a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms Part (d) Surface roughness material (silica) 5 parts by mass (e) Ion conductive material (potassium bis (trifluoromethanesulfonyl) imide, trade name "EF-N112", manufactured by Mitsubishi Materials Electronic Chemical Co., Ltd.)
1 part by mass The molar ratio [NCO / OH] between the polyisocyanate and the condensed polyester polyol was 1.1 / 1.

  The resin composition for a coating layer was applied to the outer peripheral surface of the elastic layer by a spray coating method, and heated at 160 ° C. for 30 minutes to form a coating layer having a thickness of 7 μm. Thus, a developing roller provided with the shaft, the elastic layer, and the coating layer was manufactured.

[Example 2]
Same as Example 1 except that (a) acrylic polyol (trade name "US-270", manufactured by Toagosei Co., Ltd.) was used instead of the condensation-based polyester polyol, and (b) the amount of isocyanate was 16 parts by mass. A resin composition for a coating layer was prepared to form a coating layer.

[Example 3]
(A) Polycarbonate diol (trade name “T650J”, manufactured by Asahi Kasei Corporation) in place of the condensed polyester polyol, and (b) the coating layer in the same manner as in Example 1 except that the blending amount of isocyanate was 19 parts by mass. The resin composition was prepared to form a coating layer.

[Comparative Example 1]
(C) A resin composition for a coating layer was prepared in the same manner as in Example 1 except that a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms was not added. Then, a coating layer was formed.

[Comparative Example 2]
(A) 20 parts by mass of an acrylic polyol is used instead of the polyester polyol, and (c) acrylic silicone is used instead of the (meth) acrylate copolymer containing a hydroxyl group and 1% by mass to 10% by mass of a fluorine atom. A coating layer resin composition was prepared and a coating layer was formed in the same manner as in Example 1, except that 10 parts by mass of a system graft polymer (trade name “US-270”, manufactured by Toagosei Co., Ltd.) was mixed.

[Comparative Example 3]
(A) Instead of the polyester polyol, 20 parts by mass of an acrylic polyol is blended, and (c) a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom) A resin composition for a coating layer was prepared and a coating layer was formed in the same manner as in Example 1, except that 10 parts by mass of an acrylic copolymerized fluorine polyol (trade name “TR-101”, DIC Corporation) was blended.

[Evaluation]

  Next, an image forming apparatus C610dn2 (model number, manufactured by Oki Data Co., Ltd.) was prepared, and the developing roller of this image forming apparatus was replaced with the developing roller of each of Examples and Comparative Examples, to obtain an image forming apparatus. For the obtained image forming apparatus, evaluation of filming, evaluation of white streak, evaluation of print density, evaluation of image uniformity, and evaluation of storability were performed by the following methods, and the results are shown in Table 1. Was.

(Contact angle)
The contact angle was measured using a contact angle meter (trade name “Portable Contact Angle Meter PCA-1”, manufactured by Kyowa Interface Chemical Co., Ltd.). The apparatus is set so as to be parallel to the developing roller, and a drop of hexadecane is dropped on the sample as a test liquid so that the drop diameter becomes 1 μm. For the measurement of the contact angle, the angle formed between the contact point of the sample and the droplet and the apex of the droplet was obtained by reading the angle using a camera built in the contact angle meter and software.

(Evaluation of filming)
Using an image forming apparatus equipped with the produced developing roller, at a temperature of 23 ° C. and a humidity of 55% RH, the developer adhering to the surface of the developing roller after printing 10,000 sheets was suctioned, and then the filming weight was measured. The mass transferred to the jig was measured. The filming was evaluated according to the following criteria based on the mass of the transferred developer. In this test, the filming amount passes when the evaluation is B.
-Evaluation criteria-
A: The mass of the transferred developer is 0 mg or more and less than 0.02 mg B: The mass of the transferred developer is 0.02 mg or more and less than 0.05 mg C: The mass of the transferred developer is 0.05 mg or more

(Evaluation of print density)
Solid images were printed under conditions of a temperature of 23 ° C. and a humidity of 55% RH, a temperature of 30 ° C. and a humidity of 80% RH, a room temperature of 10 ° C. and a humidity of 20% RH, respectively, and were manufactured by X-Rite. The print density of the solid image was measured using a 508 spectral densitometer. Specifically, 1.4 or more was A, 1.2 or more and less than 1.4 was B, and 1.0 or more and less than 1.2 was C.

(Evaluation of image uniformity)
A solid image was printed under the conditions of a temperature of 23 ° C. and a humidity of 55% RH, a temperature of 30 ° C. and a humidity of 80% RH, a temperature of 10 ° C. and a humidity of 20% RH, and the print density of the first sheet. And the print density of the 2000th sheet were compared. Specifically, the density step ratio between the initial print forming portion and the final print forming portion of the solid printing was determined and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: The density step ratio is within 1.1 B: The density step ratio is within 1.2 C: The density step ratio is larger than 1.2

(Evaluation of shelf life)
The developing roller was replaced with a toner cartridge, stored at a temperature of 50 ° C. and a humidity of 65% RH for one month, taken out, and left for 2 hours at a temperature of 23 ° C. and a humidity of 55% RH to perform a print test. The presence or absence of horizontal streaks after printing 20 sheets was confirmed, and after printing 20 sheets, the state of occurrence of horizontal streaks was evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: No horizontal streak can be seen B: Horizontal streak is considerably thin C: Horizontal streak can be confirmed

  Table 1 shows the evaluation results.

  As shown in Table 1, it can be seen that the developing roller on which the coating layer was formed using the composition of the present invention had excellent filming, print density, and image uniformity. On the other hand, (c) Comparative Example 1 using no (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms, Comparative Example 2 using an acrylic silicone-based graft polymer, and Comparative Example 3 using an acrylic copolymer fluorine-based polyol was inferior in filming and image uniformity.

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Axis 3 Elastic layer 4 Covering layer 6 Transfer conveyance belt 10 Image forming apparatus 11B, 11C, 11M, 11Y Image carrier 12B, 12C, 12M, 12Y Charging means 13B, 13C, 13M, 13Y Exposure means 14B, 14C, 14M, 14Y Transfer means 15B, 15C, 15M, 15Y Cleaning means 16 Recording material 20B, 20C, 20M, 20Y Developing devices 21B, 21C, 21M, 21Y, 34 Housing 22B, 22C, 22M, 22Y Developer 23B, 23C, 23M, 23Y Developer carrier 24B, 24C, 24M, 24Y Developer amount adjusting means 25B, 25C, 25M, 25Y Toner supply roller 30 Fixing means 31 Fixing roller 32 Pressure roller 33 Endless belt support roller 35 Opening 36 Endless belt 41 Cassette 42 Support La B, C, M, Y development units

Claims (5)

An elastic layer formed on the outer peripheral surface of the shaft, and a developing roller including a coating layer formed on the outer peripheral surface of the elastic layer,
The coating layer is (a) a polyol, (b) an isocyanate, (c) a (meth) acrylate copolymer containing a hydroxyl group and 1% by mass to 10% by mass of a fluorine atom, and (d) a surface roughness material. And (e) a developing roller obtained by heating and curing a composition containing an ion conductive material.   2. The developing roller according to claim 1, wherein the number of isocyanate groups in one molecule of the (b) isocyanate exceeds two.   The developing roller according to claim 1, wherein a contact angle of hexadecane of the coating layer is 45 ° or more and 80 ° or less.   A developing device comprising the developing roller according to claim 1.   An image forming apparatus comprising the developing roller according to claim 1.