JP2021060511A - 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: a shaft body 2; an elastic layer 3 that is formed on the outer periphery of the shaft body 2; and a coating layer 4 that is formed on the outer periphery of the elastic layer 3. The coating layer 4 has, on its surface, a monomolecular film in which fluorine-containing compounds having a perfluoroalkyl chain or a fluorinated polyether chain are each individually joined to the coating layer 4, and the MD-1 hardness of the surface of the developing roller 1 is 45 or less.SELECTED DRAWING: Figure 1

Description

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

A developing roller used in an image forming apparatus such as a copying machine, a printer, or a facsimile that employs an electrophotographic method has a function of transporting a developing agent 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. In recent years, it has been studied to form irregularities on the surface of a developing roller and to adjust the electrical characteristics of various materials constituting the developing roller to improve the developer transportability of the developing roller.

When the developing roller is used for a long period of time, the developing agent may adhere to the surface of the developing roller (also referred to as "filming"). In such filming, for example, the developer is deformed or destroyed by the sliding stress of the blade or the like that is in pressure contact with the developing roller when the developer is charged or adhered, and further, the developing agent is developed by frictional heat with the blade or the like. It is believed that this is caused by the melting of the agent. For this reason, there is a demand for a developing roller in which the occurrence of filming is suppressed as much as possible and the durable printing performance is stabilized.

For example, Patent Document 1 describes a conductive roller containing an ionic liquid, which prevents the developer from sticking to the surface for a long period of time. Further, in Patent Document 2, in order to maintain toner releasability and abrasion resistance, a perfluoropolyether is contained in the outermost layer, and the ratio of fluorine atoms / carbon atoms on the surface is 0.1 or more and 0.4 or less. The members for electrophotographic photography are described.

Japanese Unexamined Patent Publication No. 2011-221442 JP-A-2015-28613

However, the developing rollers described in Patent Documents 1 and 2 have a problem that the roller hardness is increased by the ionic liquid or the perfluoropolyether contained in the outermost layer. From such a point, it is required to satisfactorily prevent filming without increasing the hardness.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a developing roller, a developing device, and an image forming device in which the occurrence of filming is satisfactorily suppressed and the durable printing performance is excellent.

The developing roller of the present invention is a developing roller including a shaft body, an elastic layer formed on the outer periphery of the shaft body, and a coating layer formed on the outer periphery of the elastic layer, and the surface of the coating layer contains fluorine. A developing roller having a monomolecular film in which each compound is independently bonded to a coating layer and having an MD-1 hardness on the surface of the developing roller of 45 degrees or less.

The fluorine-containing compound preferably has a perfluoroalkyl chain or a fluorinated polyether chain.

The thickness of the monolayer is preferably 10 nm or less.

The coating layer is preferably made of urethane resin.

The elastic layer is preferably made of silicone rubber.

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

The image forming apparatus of the present invention includes the developing roller of the present invention.

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

FIG. 1 is a schematic perspective view showing an embodiment of a developing roller of the present invention. FIG. 2 is a schematic cross-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, but the following embodiments are presented for purposes of illustration, and the present invention is not limited to the embodiments shown below.

[Development roller]
FIG. 1 is a schematic perspective view showing an embodiment of a developing roller of the present invention.
As shown in FIG. 1, the developing roller 1 of the present invention includes a shaft body 2, an elastic layer 3 formed on the outer periphery of the shaft body 2, and a coating layer 4 formed on the outer periphery of the elastic layer 3. The surface of the coating layer 4 has a monomolecular film of a fluorine-containing compound, and the monomolecular film is formed by independently binding the fluorine-containing compounds to the coating layer 4.
Hereinafter, the configuration of the developing roller 1 of the present invention will be described.

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

The shaft body 2 may contain an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft body 2 may include, for example, a core body made of an insulating resin and a plating layer provided on the core body. Such a shaft body 2 can be obtained, for example, by plating a core body 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 circular shape, an elliptical shape, or a non-circular shape such as a polygon. The outer peripheral surface of the shaft body 2 may be subjected to treatments such as cleaning treatment, degreasing treatment, and primer treatment in order to improve the adhesiveness with 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 image forming apparatus to be installed. For example, when the printing target is A4 size, the length of the shaft body 2 in the axial direction 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 image forming apparatus to be installed. For example, the outer diameter of the shaft body 2 (diameter of the circumscribed circle) 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 body 2. The rubber composition for forming the elastic layer 3 preferably contains a rubber, a conductivity-imparting agent, and optionally 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. Silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber can reduce compression set, is excellent in flexibility in a low temperature environment, and has heat resistance and charging characteristics. It is particularly preferable in that it is excellent in terms of the above. Examples of the silicone rubber include crosslinked products of organopolysiloxane such as dimethylpolysiloxane and diphenylpolysiloxane.
Examples of the silicone rubber composition include an addition-curing type mirable conductive silicone rubber composition and an addition-curing type liquid conductive silicone rubber composition.

-Additional curing type mirabable conductive silicone rubber composition-
The addition-curable mirabable 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. It's okay.
R ¹ _n SiO _{(4-n) / 2} ... (1)
In the formula (1), n represents a positive number of 1.95 or more and 2.05 or less. In addition, 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, and more preferably 1 or more and 8 or less.

Examples of R ¹ include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group, cycloalkyl group such as cyclohexyl group, vinyl group, allyl group, butenyl group and hexenyl group. Examples thereof include an aryl group such as an alkenyl group, a phenyl group and a tolyl group, and an aralkyl group such as a β-phenylpropyl group. Further, R ¹ may be a group in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with substituents. 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, a cyanoethyl group and the like.

(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, or a trivinylsilyl group. It is preferably sealed with a trialal kill silyl group or the like.

The organopolysiloxane (A) preferably has two or more alkenyl groups in the molecule. (A) organopolysiloxane, 0.001 mol% or more of ^{R 1} 5 mol% or less (more preferably at least 0.01 mol% 0.5 mol%) preferably has an alkenyl group. As the alkenyl group contained in (A) organopolysiloxane, a vinyl group is particularly preferable.

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

The organopolysiloxane (A) preferably has a kinematic viscosity at 25 ° C. of 100 cSt or more, and more preferably 100,000 cSt or more and 10000000 cSt or less. Further, the degree of polymerization of (A) organopolysiloxane is preferably, for example, 100 cSt or more, and more preferably 3000 cSt or more and 10000 cSt or less.

Examples of the filler (B) include silica-based fillers. Examples of the silica-based filler include fumes silica, precipitated silica and the like.

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 preferably used.} Here, R ² may be a group having a vinyl group or an amino group, and may be, 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 conventional method. As the surface-treated silica-based filler, a commercially available product may be used, for example, J.I. M. Examples thereof include the trade name "Zeothix 95" manufactured by HUBER Co., Ltd.

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

Examples of the (C) conductivity-imparting agent include carbs, metals, genus oxides, metal compounds, conductive polymers, and ionic liquids. The blending amount of the (C) conductivity-imparting agent is preferably 0.5 parts by mass or more, and more preferably 1 part by mass or more, with respect to 100 parts by mass of (A) organopolysiloxane. The blending amount of the (C) conductivity-imparting agent is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, with respect to 100 parts by mass of (A) organopolysiloxane.

The addition-curable mirabable conductive silicone rubber composition may further contain additives other than (A) to (C). Additives include, for example, auxiliaries (chain extenders, cross-linking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, etc. Examples thereof include emulsifiers, ionic conductive agents, heat resistance improvers, flame retardant improvers, acid receivers, thermal conductivity improvers, mold release agents, solvents and the like.

Specific examples of the additive include (A) both-terminal silanol group encapsulation of dimethylsiloxane oil, polyether-modified silicone oil, silanol, diphenylsilanediol, α, ω-dimethylsiloxanediol, etc., which have a lower degree of polymerization than organopolysiloxane. Dispersants such as low molecular weight siloxane and silane can be mentioned. Specific examples of the additive include heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. Further, as the additive, various carbon functional silanes, various olefin elastomers and the like for improving adhesiveness, molding processability and the like may be used.

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

As the organopolysiloxane (D), the compound represented by the following average composition formula (2) is suitable.
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, and more preferably 1.95 or more and 2.05 or less. R ^{4 also} represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. Provided that at least two of R ⁴ in one molecule is an alkenyl group. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 12 or less, and more preferably 1 or more and 8 or less.

As R ⁴ , the same group as that exemplified as R ^{1 can be exemplified.} Also, at least two of R ⁴ in one molecule is an alkenyl group, R ⁴ other than it is preferably 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). The content of the alkenyl group in the (D) organopolysiloxane is preferably, for example, 1.0 × ^10-6 mol / g or more and 5.0 × 10 ^-3 mol / g or less, preferably 5.0 × 10 ^{−. More preferably, it is 6} mol / g or more and 1.0 × 10 ^-3 mol / g or less.

The organopolysiloxane (D) is preferably liquid at 25 ° C., preferably has a viscosity at 25 ° C. of 100 mPa · s or more and 1000000 mPa · s or less, and more preferably 200 mPa · s or more and 100,000 mPa · s or less. preferable. The average degree of polymerization of (D) organopolysiloxane is preferably 100 or more and 800 or less, and more preferably 150 or more and 600 or less.

As the organohydrogenpolysiloxane (E), the compound represented by the following average composition formula (3) is suitable.
R ⁵ _b H _c SiO _{(4-bc) / 2} ... (3)
In formula (3), b indicates a positive number of 0.7 or more and 2.1 or less, c indicates a positive number of 0.001 or more and 1.0 or less, and bc indicates 0.8 or more and 3.0 or less. Is. R ^{5 also} 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 10 or less. As R ⁵ , the same group as that exemplified as R ^{1 can be exemplified.}

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

(E) In the organohydrogenpolysiloxane, the content of the hydrogen atom bonded to the silicon atom is preferably 0.001 mol / g or more and 0.017 mol / g or less, and 0.002 mol / g or more and 0.015 mol / g or less. It is more preferably g or less.

Examples of the organohydrogenpolysiloxane (E) include a two-terminal trimethylsiloxy group-blocking methylhydrogenpolysiloxane, a two-terminal trimethylsiloxy group-blocking dimethylsiloxane / methylhydrogensiloxane copolymer, and a two-terminal dimethylhydrogensiloxy group-blocking. 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 copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit _Examples thereof include a copolymer composed of (C ₆ H ₅ ) SiO 3/2 unit.

The blending amount of (E) organohydrogenpolysiloxane is preferably 0.1 part by mass or more and 30 parts by mass or less, and 0.3 part by mass or more and 20 parts by mass with respect to 100 parts by mass of (D) organopolysiloxane. The following is more preferable. The molar ratio of Si—H of (E) organohydrogenpolysiloxane to the alkenyl group of (D) organopolysiloxane is preferably 0.3 to 5.0, preferably 0.5 to 2.5. Is more preferable.

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

The average particle size of the filler (F) is preferably 1 μm or more and 30 μm or less, and more preferably 2 μm or more and 20 μm or less. (F) When the average particle size of the filler is 1 μm or more, the change in volume resistivity with time is further suppressed. Further, when the average particle size of the filler (F) is 30 μm or less, the elastic layer 3 having further excellent durability can be obtained. The average particle size of the filler (F) can be measured as a median diameter 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 lowered, the change in volume resistivity with time is further suppressed, and the elastic layer 3 having further excellent durability. Can be obtained. (F) The bulk density of the filler can be determined based on the method of measuring the apparent specific gravity of JIS K 6223.

Examples of the (F) filler include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, hollow filler and the like. Among these, as the (F) filler, diatomaceous earth, pearlite, and pulverized foamed pearlite can be preferably used.

The blending amount of the (F) filler is preferably 5 parts by mass or more and 100 parts by mass or less, and more preferably 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of (D) organopolysiloxane. ..

Examples of the (G) conductivity-imparting agent include carbon, metal, metal oxide, metal compound, conductive polymer, and ionic liquid. The blending amount of the (G) conductivity-imparting agent is preferably 0.5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of (D) organopolysiloxane, and is 1 part by mass or more and 10 parts by mass or less. More preferably.

The (H) addition reaction catalyst may be any catalyst that can activate the addition reaction between (D) organopolysiloxane and (E) organohydrogenpolysiloxane. Examples of the (H) addition reaction catalyst include catalysts having a platinum group element. Examples of the catalyst having a platinum group element include platinum-based catalysts (for example, platinum black, secondary platinum chloride, platinum chloride acid, a reaction product of platinum chloride acid and a monovalent alcohol, and a complex of platinum chloride acid and olefins. , Platinum bisacetoacetate, etc.), palladium-based catalysts, rhodium-based catalysts, etc.

The blending amount of the addition reaction catalyst (H) may be the amount of the catalyst. For example, the amount of the (H) addition reaction catalyst compounded is such that the amount of platinum group elements is 0.5 mass ppm or more and 1000 mass ppm or less with respect to the total mass of (D) organopolysiloxane and (E) organohydrogenpolysiloxane. It is preferable that the amount is 1 mass ppm or more and 500 mass ppm or less.

The addition-curable liquid conductive silicone rubber composition may further contain additives other than (D) to (H). Additives include, for example, auxiliaries (chain extenders, cross-linking agents, etc.), foaming agents, dispersants, antioxidants, antioxidants, ionic conductive agents, pigments, colorants, processing aids, softeners, plastics. Examples thereof include agents, emulsifiers, heat resistance improvers, flame retardant improvers, acid receivers, thermal conductivity improvers, mold release agents, diluents, reactive diluents, solvents and the like.

Specific examples of the additive include dispersants such as low molecular weight siloxane ester, polyether-modified silicone oil, silanol, and phenylsilanediol. Further, heat resistance improvers such as iron octylate, iron oxide and cerium oxide can be mentioned. Further, various carbon functional silanes, various olefin elastomers and the like for improving adhesiveness, molding processability and the like may be used. Further, a halogen compound or the like that imparts flame retardancy may be used.

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

The thickness of the elastic layer 3 is not particularly limited, and is preferably 0.1 mm or more and 6 mm or less, and more preferably 1 mm or more and 4 mm or less. The thickness in the present specification indicates the thickness in the 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 preferably 6 mm or more and 25 mm or less, and more preferably 7 mm or more and 21 mm or less.

The outer peripheral surface of the elastic layer 3 is subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, excimer treatment, UV treatment, itro treatment, and frame treatment for the purpose of improving the adhesiveness with the coating layer 4. It's okay.

The elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by simultaneously or continuously performing heat curing and molding by a known molding method. The method for curing the rubber composition may be any method as long as the heat required for curing the rubber composition can be applied, and the method for forming the elastic layer 3 is particularly continuous vulcanization by extrusion molding, pressing, mold molding by injection, etc. There are no restrictions. For example, when the rubber composition is an addition-curable mirable 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 the case, for example, a molding method using a mold can be selected. Further, it may be formed by grinding or polishing an elastic body (cured product of a silicone rubber composition) formed on the shaft body 2.

The heating temperature at which the rubber composition is cured is preferably 100 ° C. or higher and 500 ° C. or lower, and more preferably 120 ° C. or higher and 300 ° C. or lower in the case of the addition-curable mirrorable conductive silicone rubber composition. The heating time is preferably several seconds or more and 1 hour or less, and more preferably 10 seconds or more and 35 minutes or less. In the case of the addition-curable liquid conductive silicone rubber composition, the heating temperature is preferably 100 ° C. or higher and 300 ° C. or lower, and more preferably 110 ° C. or higher and 200 ° C. or lower. The heating time is preferably 5 minutes or more and 5 hours or less, and more preferably 1 hour or more and 3 hours or less. Further, if necessary, secondary vulcanization may be performed. In the case of the addition-curing type mirable conductive silicone rubber composition, for example, curing conditions of about 1 hour or more and 20 hours or less at 100 ° C. or higher and 200 ° C. or lower are selected. Further, in the case of the addition-curing type liquid conductive silicone rubber composition, for example, curing conditions of about 2 hours or more and 70 hours or less at 120 ° C. or higher and 250 ° C. or lower are selected. Further, the rubber composition can be easily foamed and cured by a known method to easily form a sponge-like elastic layer having bubbles.

(Coating layer)
The coating layer 4 is the outer circumference of the elastic layer 3 and is provided on the outermost surface of the developing roller 1. In the coating layer 4, the resin composition for the coating layer is applied to the outer peripheral surface of the elastic layer 3 or the primer layer formed as desired, and then the coated resin composition for the coating layer is heat-cured. It is formed.
The coating layer 4 may be a layer made of urethane resin. Examples of the resin composition for a coating layer include those containing (a) polyol, (b) isocyanate, (c) surface roughness material, and (d) conductivity-imparting agent.
Hereinafter, each component (a) to (d) of the resin composition for a coating layer will be described.

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

The polyether polyols include, for example, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polypropylene glycol-ethylene glycol, polytetramethylene ether glycols, copolymer polyols of tetrahydrofuran and alkylene oxide, various modified products thereof, or mixtures thereof. Can be mentioned.

Polyester polyols have two or more ester bonds and two or more hydroxyl groups in the molecule. Examples of the polyester polyol include a condensation reaction 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 are hydroxyl group-containing monomers and other olefinically unsaturated monomers such as (meth) acrylic acid esters, styrene, α-methylstyrene, vinyltoluene, vinyl esters, maleic acid monoalkyl esters and maleic acid dialkyl esters. , Fumaric acid monoalkyl esters and fumaric acid dialkyl esters, α-olefins and copolymers with other unsaturated monomers and unsaturated polymers.

Polycarbonate polyols have two or more carbonate bonds and two or more hydroxyl groups in the molecule. Examples of the polycarbonate polyol include a condensation reaction product of the polyol and the carbonate compound. Moreover, as a carbonate compound, for example, a dialkyl carbonate, a diaryl carbonate, an alkylene carbonate and the like can be mentioned. Examples of the polyol used as a raw material for the polycarbonate polyol include diols such as hexanediol and butanediol, and triols such as 2,4-butanediol.
The polyol preferably has a number average molecular weight of 1000 to 8000, and more preferably 1000 to 5000, in terms of excellent compatibility with isocyanate and the like, which will be described later. The number average molecular weight is the molecular weight when converted to 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 it has excellent storage stability and the reaction rate can be easily controlled.
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 can be mentioned.
Examples of the aromatic isocyanate include xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (also referred to as tolylene diisocyanate, TDI), 3,3'-bitrylene-4,4'-diisocyanate, 3,3. '-Dimethyldiphenylmethane-4,4'-diisocyanate, 2,4-toluene diisocyanate uretidinedione (2,4-TDI diisocyanate), xylene diisocyanate, naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI), Examples thereof include trizine diisocyanate (TODI) and metaphenylene diisocyanate.
Derivatives include polyisocyanate polynuclears, urethane modified products (including urethane prepolymers) modified with polyols, dimer by uretidine formation, isocyanurate modified products, carbodiimide modified products, uretonimine modified products, alohanate modified products, etc. Urea modified products, bullet modified products and the like can be mentioned. As the polyisocyanate, one type 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 the coating layer is preferably a polyisocyanate. (B) The number of isocyanate groups in one molecule of isocyanate is preferably more than 2, more preferably 2.5 or more, still more preferably 3 or more.
The mixing ratio of the mixture of the polyol and the polyisocyanate is not particularly limited, but usually, the molar ratio (NCO / OH) of the hydroxyl group (OH) contained in the polyol and the isocyanate group (NCO) contained in the polyisocyanate is 0. It is preferably 7. or more and 1.15 or less. This molar ratio (NCO / OH) is more preferably 0.85 or more and 1.10 or less in that hydrolysis of polyurethane can be prevented. Actually, in consideration of the work environment and work error, an amount equivalent to 3 to 4 times the appropriate molar ratio may be blended.

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

(C) Surface Roughness Material The coating layer 4 contains a surface roughness material. The surface roughness material is particles that adjust 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, and 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, the toner transferability is improved and more excellent printing characteristics can be obtained. The average particle size of the surface roughness material can be measured as a median diameter using a particle size distribution measuring device by a laser light diffraction method.

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

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

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

(D) Conductivity-imparting agent The coating layer 4 may further contain a conductivity-imparting agent. The conductivity-imparting agent is not particularly limited as long as it is a component that can impart conductivity to the coating layer 4. Examples of the conductivity-imparting agent include carbon black (for example, acetylene black and Ketjen black), ionic conductive agents, metals, metal oxides, conductive polymers, antistatic agents, ionic conductive resins, and surfactants. Can be mentioned. The blending amount of the conductivity-imparting agent is not particularly limited, and may be appropriately adjusted according to the type of the conductivity-imparting agent, the desired conductivity performance, and the like. Further, the conductivity-imparting agent may be used alone or in combination of two or more.

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

In the coating layer 4, a resin composition for a coating layer is applied onto the elastic layer 3, and (a) a polyol component and (b) an isocyanate component are polymerized and cured by heating or the like. The solvent used in 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.

The coating of the resin composition for a coating layer is, for example, a coating method of applying a coating liquid of a resin composition for a coating layer, a dipping method of immersing an elastic layer or the like in the coating liquid, an elastic layer of the coating liquid, or the like. It is carried out by a known coating method such as a spray coating method of spraying on. The coating layer resin composition may be applied as it is, or the coating layer resin composition may be coated with, for example, alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, ethyl acetate, butyl acetate and the like. A volatile solvent such as an ester solvent of the above, or a coating liquid to which water is added may be applied. The method for curing the coating layer resin composition coated in this manner may be any method as long as the heat required for curing the coating layer resin composition or the like can be applied. For example, the coating layer resin composition. Examples thereof include a method of heating the elastic layer or the like coated with the resin composition with a heater, a method of allowing the elastic layer or the like coated with the resin composition to stand at a high temperature, and the like. The heating temperature when the resin composition for a coating layer is heat-cured is, for example, preferably 100 ° C. or higher and 200 ° C. or lower, more preferably 120 ° C. or higher and 160 ° C. or lower, and the heating time is 10 minutes or longer. It is preferably 120 minutes or less, and more preferably 30 minutes or more and 60 minutes or less.
In the coating layer formed in this way, when an ionic conductive material is used as the conductivity-imparting agent, the precursor forming the resin and the ionic conductive material may react and become one. , May form a complex. Further, the ionic conductive material may not react with the precursor forming the resin and may be dispersed in the resin.

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

(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.
Among these intermediate layers, in particular, the adhesive layer and the primer layer provided between the elastic layer 3 and the coating layer 4 are adjusted in their electrical characteristics to adjust the electrical characteristics of the developing roller 1. Can be done. Thereby, the developing performance of the developing roller 1 can be satisfactorily adjusted.

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

(Monolayer of fluorine-containing compound)
The developing roller 1 of the present embodiment has a monolayer of a fluorine-containing compound on the surface of the coating layer 4.
The monolayer of the fluorine-containing compound preferably has a perfluoroalkyl chain or a fluorinated polyether chain. The following fluorine-containing compounds are preferable.

-Fluorine-containing compound having a perfluoroalkyl chain-
In the present invention, the fluorine-containing compound having a perfluoroalkyl chain is represented by the following formula (4).

CF ₃ (CF ₂ ) _r- X ^1- Z ... (4)
In equation (4), the symbols indicate the following.
X ¹ : Single bond or alkylene Z having 1 to 3 carbon atoms: A group represented by the following formula (4-1), a group represented by the following formula (4-2), and a group represented by the following formula (4-3). Group represented or group represented by the following formula (4-4) -CH ₂ CH ₂ CH ₂ SiL _m R _n ... (4-1)
_{-CH 2 CH (SiL m R n} ) CH 3 ··· (4-2)
-CH ₂ CH = CH ₂ ... (4-3)
-CH = CHCH ₃ ... (4-4)
r is an integer of 10 or less, more preferably 6 or less.
The symbols in the equations (4-1) to (4-4) are as follows.
L: Hydrolyzable group R: A monovalent hydrocarbon group m is an integer of 1 to 3, n is an integer of 0 to 2, and m + n = 3.

L is a hydrolyzable group, and examples thereof include an alkoxy group, a halogen atom, an acyl group, and an isocyanate group. As the alkoxy group, an alkoxy group having 1 to 4 carbon atoms is preferable. L becomes a hydroxyl group bonded to a silicon atom by a hydrolysis reaction. Si-L becomes a silanol group (-Si-OH) by a hydrolysis reaction. The silanol group can react with the hydroxyl group on the urethane surface of the coating layer to form a chemical bond, and this reaction chemically bonds the compound (1) to the surface of the base material.

R is a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group and an allyl group. R is particularly preferably a monovalent saturated hydrocarbon group. The monovalent saturated hydrocarbon group preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms. From the viewpoint of ease of synthesis, R is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably an alkyl group having 1 to 2 carbon atoms.

n is an integer of 0 to 2 and m + n = 3. n is preferably 0 or 1, and 0 is particularly preferable. When n is 0 or 1, it means that m is 3 or 2.

-Sil _m The _{R n, -Si (OCH 3)} 3, -SiCH 3 (OCH 3) 2, -Si (OCH 2 CH 3) 3, -SiCl 3, -Si (OCOCH 3) 3, -Si ( NCO) ₃ is mentioned. _{-Si (OCH 3} ) ₃ is preferable from the viewpoint of ease of handling in industrial manufacturing.

Examples of the fluorine-containing compound having a perfluoroalkyl chain include a commercially available SF coat (AGC Seimi Chemical Co., Ltd.).

-Fluorine-containing compound having a fluorinated polyether chain-
In the present invention, the fluorine-containing compound having a perfluoroalkyl chain is represented by the following formula (5).

A ^2- O-Q- (C _b F _{2 b} O) _d- X ^2- O-Z ... (5)
The symbols in the formula (5) indicate the following.
A ² : Perfluoroalkyl group having 1 to 20 carbon atoms, or Z below
Q: Single bond, -CH _2- , -CHF-, -Q ^1- CH _2- , -Q ^1- CHF-, -Q ¹ -O-CH _2- , -Q ¹ -O-CHF-, -Q ^1- CH _2- O- or Q ^1- CHFO-
Q ¹ : Fluoroalkylene group having 1 to 10 carbon atoms, fluoroalkylene group having 2 to 10 carbon atoms having an ether oxygen atom between carbon atoms, alkylene group having 1 to 10 carbon atoms, or between carbon atoms. The alkylene group b, d: b having 2 to 10 carbon atoms having an etheric oxygen atom is an integer of 1 to 10, d is an integer of 1 to 200, and when d is 2 or more, (C _b F). _2b O) d may be made of two or more different of _C b _{F 2b} O of b.
X ² : _{Divalent organic group having no CF 2} O Z: Same as Z in the above formula (4).

X ² is a divalent organic group having no _{CF 2 O.} As the divalent organic group, a fluoroalkylene group having 1 to 6 carbon atoms and an alkylene group having 1 to 6 carbon atoms are preferable. From the viewpoint of ease of production, a fluoroalkylene group having 1 to 6 carbon atoms containing one or more hydrogen atoms is more preferable, and a group represented by the following formula (6) is particularly preferable.

-(CF ₂ ) _a CFX ^3- CH ₂ -... (6)
However, in the formula (6), a is 0 to 2, X ³ is F or CF ₃ .

The group (6), for _{example, -CF 2 CH 2 -, -} CF 2 CF 2 CH 2 -, - CF 2 CF 2 CF 2 CH 2 -, - CF (CF 3) CH 2 - and the like.

Examples of the fluorine-containing compound having a fluorinated polyether chain include commercially available SURECO (AGC Inc.).

The monolayer can be formed by the following method. First, the composition containing the fluorine-containing compound is applied onto the coating layer by spray coating, dip coating, brush coating, dry cloth coating or the like to form a coating film. After the coating film is dried, it is heated at 80 ° C. to 150 ° C. for about 10 to 30 minutes to form a monolayer. Finally, it may have a step of rinsing with a fluorine-based solvent.

The thickness of the monolayer is preferably 10 nm or less. The coating with the monolayer may be a cumulative monolayer.

The MD-1 hardness of the surface of the developing roller 1 of the present invention is 45 or less from the viewpoint of preventing the developer from being damaged. The MD-1 hardness of the surface of the developing roller 1 is preferably 43 or less.
An MD-1 hardness tester (“Micro Rubber Hardness Tester MD-1” manufactured by Polymer Meter Co., Ltd.) is used to measure the MD-1 hardness. The value read in 3 seconds for the peak hold mode and the hold time is defined as the MD-1 hardness. In principle, the MD-1 hardness tester conforms to the type A durometer described in JIS K6253.

By having a monomolecular film composed of a fluorine-containing compound as in the present invention, water and oil repellency is imparted to the coating layer, and the external silica of the developer does not adhere, so that the filming is good. Can be prevented. Further, since the fluorine-containing group is not introduced into the resin constituting the coating layer as in the prior art, filming can be prevented without increasing the hardness of the coating layer.

[Developer and image forming device]
The developing roller 1 of the present invention can be suitably used as a developing agent carrier in a developing apparatus 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 apparatus and an image forming apparatus including the developing roller 1 of the present invention will be described with reference to FIG.

The image forming apparatus 10 connects a plurality of image carriers 11B, 11C, 11M and 11Y mounted on the developing units B, C, M and Y of each color (black, cyan, magenta, yellow) in series on the transfer transfer belt 6. It is a tandem type color image forming apparatus arranged in, and development units B, C, M and Y are arranged in series on a transfer transfer belt 6. The developing unit B carries an image via an image carrier 11B, for example, a photoconductor (also referred to as a photosensitive drum), a charging means 12B, for example, a charging roller, an exposure means 13B, a developing device 20B, and a transfer transfer belt 6. A transfer means 14B that comes into contact with the body 11B, for example, a transfer roller and a cleaning means 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 the developing agent 22B as shown in FIG. Therefore, in the image forming apparatus 10, the developing roller 1 is mounted as the developing agent carriers 23B, 23C, 23M and 23Y. Specifically, the developing apparatus 20B includes a housing 21B for accommodating a one-component non-magnetic developer 22B, a developing agent supporting body 23B for supplying the developing agent 22B to the image carrier 11B, and a developing agent supporting body 23B. A toner supply roller 25B for supplying the developer 22B and a developer amount adjusting means 24B for adjusting the thickness of the developer 22B, for example, a blade are provided. In the developing apparatus 20B, the developer amount adjusting means 24B is in contact with or pressure-contacted with the outer peripheral surface of the developer carrier 23B as shown in FIG. That is, the developing device 20B is a "contact developing device". The developing units C, M and Y are basically configured in the same manner as the developing unit B, and the same elements are designated by the same reference numerals and symbols C, M or Y indicating each unit, and the description thereof will be omitted. ..

In the image forming apparatus 10, the developer carrier 23B of the developing apparatus 20B is arranged so that its surface is in contact with or pressure-contacted with the surface of the image carrier 11B. Similar to the developing device 20B, the developing devices 20C, 20M and 20Y are also arranged so that the surface of the developing devices 23C, 23M and 23Y is in contact with or pressed against 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 means 30 is arranged on the downstream side of the developing unit Y. The fixing means 30 includes a fixing roller 31, an endless belt support roller 33 arranged in the vicinity of the fixing roller 31, a fixing roller 31, and an endless belt in a housing 34 having an opening 35 through which the recording body 16 is passed. An endless belt 36 wound around the support roller 33 and a pressure roller 32 arranged to face the fixing roller 31 are provided, and the fixing roller 31 and the pressure roller 32 are in contact with each other or pressure contacted with each other via the endless belt 36. It is a pressure heat fixing device that is rotatably supported so as to perform. A cassette 41 for accommodating the recording body 16 is installed at the bottom of the image forming apparatus 10. The transfer transfer belt 6 is wound around a plurality of support rollers 42.

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

The image forming apparatus 10 forms a color image on the recording body 16 as follows. First, in the developing unit B, an electrostatic latent image is formed on the surface of the image carrier 11B charged by the charging means 12B by the exposure means 13B, 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 to 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. The color image is visualized. Next, in the recording body 16 in which the color image is visualized, the color image is fixed to the recording body 16 as a permanent image by the fixing means 30. In this way, a color image can be formed on the recording body 16.

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

The developing apparatus and the image forming apparatus of the present invention are not limited to those described above, and various modifications can be made as long as the object of the present invention can be achieved.

The image forming apparatus is an electrophotographic image forming apparatus, but in the present invention, the image forming apparatus is not limited to the electrophotographic system, and may be, for example, an electrostatic type image forming apparatus. .. Further, the image forming apparatus in which the developing rollers of the present invention are arranged is not limited to a tandem type color image forming apparatus in which a plurality of image carriers equipped with developing units of each color are arranged in series on a transfer transfer belt, for example. , A monochrome image forming apparatus provided with a single developing unit, a 4-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier onto an endless belt, or the like. 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, it may be a two-component magnetic developer.

The image forming apparatus is a contact type image forming apparatus in which the surface of the developer image carrier is arranged by contacting or pressing against the surface of the image carrier. The image forming apparatus of the present invention may be a non-contact image forming apparatus arranged with a gap so that the surface of the developer carrier does not come into contact with the surface of the image carrier.

Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments. It will be apparent to those skilled in the art that improvements can be made. Further, it is clear from the description of the claims that the invention with such changes or improvements may be included in the technical scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the examples shown below.

[Example 1]
(Formation of primer layer)
The shaft body (made by SUM22, diameter 10 mm, length 275 mm) subjected to electroless nickel plating is washed with ethanol, and the surface thereof is made of a silicone primer (trade name "Primer No. 16", manufactured by Shin-Etsu Chemical Co., Ltd.). ) Was applied. The primer-treated shaft was fired at a temperature of 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, hydrophobized fumed silica (trade name "R-972") having 100 parts by mass of dimethylpolysiloxane (polymerization degree 300) with both ends sealed with a dimethylvinylsiloxy group and a BET specific surface area of 110 m ^{2 / g.} , Nippon Aerosil Co., Ltd.) 1 part by mass, average particle size 6 μm, bulk density 0.25 g / cm ³ diatomaceous earth (trade name “Opreite W-3005S”, manufactured by Chuo Silica Co., Ltd.) 40 parts by mass, and , 5 parts by mass of acetylene black (trade name "Denka Black HS-100", manufactured by Denka Co., Ltd.) was placed in a planetary mixer, stirred for 30 minutes, and then passed through three rolls once. This was returned to the planetary mixer again, and 2.1 parts by mass of methylhydrogenpolysiloxane (degree of polymerization 17, Si—H amount 0.0060 mol / g) having Si—H groups at both ends and side chains, ethynylcyclohexanol. 0.1 parts by mass and 0.1 parts by mass of a platinum-based catalyst (Pt concentration 1% by mass) were added, and the mixture was stirred, 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 injection-molded using a mold to form an elastic body made of a rubber material on the outer peripheral surface of the shaft body. In injection molding, the addition-curable liquid conductive silicone rubber composition was heated at 120 ° C. for 10 minutes to be cured, and secondary vulcanization was performed 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.
Table 1 shows the total contents (parts) of (a) polyol, (b) isocyanate, (c) surface roughness material, and (d) ionic conductive material in the resin composition for the coating layer. Shown.

-Resin composition for coating layer-
(A) Polyester polyol 28 parts by mass (b) Hexamethylene diisocyanate (trade name "Duranate TPA-100", manufactured by Asahi Kasei Co., Ltd.) 14 parts by mass (c) Surface roughness material (silica) (trade name "ACEMATT412", ebonic (Made by Japan Co., Ltd.) 3 parts by mass (d) Carbon black (Product name "Talka Black # 5500", manufactured by Tokai Carbon Co., Ltd.)
5 parts by mass

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 layer thickness of 15 μm.

(Monolayer of fluorine-containing compound)
As the composition containing the fluorine-containing compound, the composition shown below was used.
SURECO AF (manufactured by AGC Inc.) An appropriate amount of SURECO was applied by dipping and then heated at 120 ° C. for 30 minutes to form a monolayer.
As described above, a developing roller provided with a shaft body, an elastic layer and a coating layer was produced.

[Example 2]
A developing roller was produced in the same manner as in Example 1 except that the composition containing the fluorine-containing compound was replaced with SF Coat (manufactured by AGC Inc.).

[Comparative Example 1]
In the resin composition for the coating layer, the developing roller was formed by the same method as in Example 1 except that (a) the polyol was 20 parts by mass of the polyester polyol and 6 parts by mass of the fluorine polyol, and no monolayer was formed. Obtained.

[Comparative Example 2]
A developing roller was obtained by the same method as in Comparative Example 1 except that (a) the polyol was 20 parts by mass of a fluorine polyol in the resin composition for the coating layer.

[Evaluation]
An image forming apparatus C610dn2 (model number, manufactured by Oki Data Corporation) was prepared, and the developing rollers of the image forming apparatus were replaced with the developing rollers of the respective Examples and Comparative Examples to obtain an image forming apparatus. The obtained image forming apparatus was evaluated for filming, print density, and image uniformity by the following methods, and the results are shown in Table 1.

(Measuring method of MD-1 hardness)
Using an MD-1 hardness tester (manufactured by Polymer Meter Co., Ltd., "Micro rubber hardness tester MD-1"), press the push needle of the MD-1 hardness tester against the roll surface, and the peak hold mode and hold time are 3. The value read in seconds was taken as MD-1 hardness.

(Evaluation of filming)
Using an image forming apparatus equipped with the produced developing roller, the developer adhering to the surface of the developing roller after printing 10,000 sheets under the conditions of a temperature of 23 ° C. and a humidity of 55% RH is sucked and then the filming weight is measured. The mass transferred to the jig was measured. The filming evaluation was based on the mass of the transferred developer according to the following criteria. 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)
A solid image is printed under the conditions of temperature 23 ° C. and humidity 55% RH, temperature 30 ° C. and humidity 80% RH, temperature 10 ° C. and humidity 20% RH, and manufactured by X-Rite. The print density of the solid image was measured using a 508 spectrophotometer.
-Evaluation criteria-
A: 1.4 or more B: 1.2 or more and less than 1.4 C: 1.0 or more and less than 1.2

(Evaluation of image uniformity)
Under the conditions of temperature 23 ° C. and humidity 55% RH, temperature 30 ° C. and humidity 80% RH, the conditions of temperature 10 ° C. and humidity 20% RH are changed in a cycle to perform 10000 predetermined print patterns, and the next day solid image. 3 sheets were printed, and the print density of a solid image was measured using a 508 spectrophotometer manufactured by X-Rite.
-Evaluation criteria-
A: Concentration step ratio is 1.4 or more B: Concentration step ratio is 1.2 or more and less than 1.4 C: Concentration step ratio is 1.0 or more and less than 1.2

The evaluation results are shown in Table 1.

As shown in Table 1, it can be seen that the developing roller having the coating layer of the present invention is excellent in all of filming, print density, and image uniformity.
On the other hand, as in Comparative Examples 1 and 2, a developing roller that does not have a monolayer and uses a fluorine polyol as the polyol of the coating layer has high hardness and is inferior in evaluation of filming, print density, and image uniformity. ..

1 Develop roller 2 Axis 3 Elastic layer 4 Coating layer 6 Transfer transport belt 10 Image forming device 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 Recorder 20B, 20C, 20M, 20Y Developer 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 Pressurizing roller 33 Endless belt support roller 35 Opening 36 Endless belt 41 Cassette 42 Support roller B, C, M, Y Development unit

Claims (7)

A developing roller including a shaft body, an elastic layer formed on the outer periphery of the shaft body, and a coating layer formed on the outer periphery of the elastic layer.
A developing roller having a monomolecular film on the surface of the coating layer in which fluorine-containing compounds are independently bonded to the coating layer, and the MD-1 hardness of the surface of the developing roller is 45 or less. The developing roller according to claim 1, wherein the fluorine-containing compound has a perfluoroalkyl chain or a fluorinated polyether chain. The developing roller according to claim 1 or 2, wherein the monolayer has a thickness of 10 nm or less. The developing roller according to any one of claims 1 to 3, wherein the coating layer is made of urethane resin. The developing roller according to any one of claims 1 to 4, wherein the elastic layer is made of silicone rubber. A developing apparatus including the developing roller according to any one of claims 1 to 5. An image forming apparatus including the developing roller according to any one of claims 1 to 5.

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