JP6926375B2 - Developing rollers, developing equipment and image forming equipment - Google Patents

Description

The present invention relates to a developing roller having excellent toner releasability and satisfactorily suppressing the occurrence of filming, a developing apparatus provided with the developing roller, and an image forming apparatus.

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. 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 to improve the developer transportability of the developing roller.

Here, when the developing roller is used for a long period of time, the developing agent may adhere to the surface thereof (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. Conventionally, in the manufacture of a developing roller, it has been required to improve the toner releasability and suppress the occurrence of filming as much as possible to provide a developing roller having stable durable printing performance.

As such a developing roller, for example, in Patent Document 1, an elastic layer having conductivity is formed on the outer periphery of a good conductive shaft, and a one-component developer is supported on the surface of the elastic layer to support the developing agent. In a developing roller that forms a thin layer and supplies the developer, the elastic layer has a roller resistance of R ₁ and this resin component when the elastic layer has a resin component on its surface and does not have this resin component. A developing roller is disclosed, which satisfies the relationship log (R ₂ / R ₁ ) ≤ 3 when the roller resistance in the case is R _2.

Further, Patent Document 2 has at least one elastic layer on the shaft core and at least one coating layer on the outer periphery thereof, carries a developer, carries the developer, and contacts the photosensitive drum to form an electrostatic latent image. In the developing roller for visual imaging, the coating layer is made of a thermoplastic resin, the thickness thereof is 5.0 nm or more and less than 2.0 μm, and the micro rubber hardness Hd on the surface of the elastic layer is 21 or more and 50 or less. The difference (Hs-Hd) between the micro rubber hardness Hd on the surface of the elastic layer and the micro rubber hardness Hs on the surface of the developing roller is 0 or more and 5 or less, the surface roughness Ra ₁ on the surface of the elastic layer and the surface roughness of the developing roller. A developing roller is disclosed in which the difference in Ra _{2 (Ra 1 − Ra 2} ) is between −0.20 μm and 0.20 μm.

Japanese Unexamined Patent Publication No. 10-69165 JP-A-2007-316524

Here, in recent image forming apparatus, finer print characteristics are required as the image forming is refined and speeded up, and in the developing roller used in the image forming apparatus, the toner releasability is further improved. There is a demand for characteristics that can suppress the occurrence of filming. However, the developing rollers described in Patent Documents 1 and 2 do not have sufficient toner releasability to the extent that they can sufficiently correspond to the performance of recent image forming apparatus, and the occurrence of filming is sufficiently suppressed. It wasn't done. Therefore, the present invention has been made in view of the above points, and a developing roller having excellent toner releasability and satisfactorily suppressing the occurrence of filming, a developing device provided with the developing roller, and an image forming device. The purpose is to provide.

In view of the above problems, the inventors of the present invention have conducted diligent research. As a result, a graft prepolymer and a polyisocyanate having a branched chain composed of a silicone chain and any one main chain selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and having at least two or more hydroxyl groups. The present invention has been completed by finding that the development roller on which the coating layer is formed has a minute uneven shape by applying and curing the mixture containing the above-mentioned material, so that the occurrence of filming is satisfactorily suppressed. I arrived. Specifically, the present invention provides the following.

(1) A shaft body, an elastic layer provided on the outer peripheral surface of the shaft body, and a coating layer provided outside the elastic layer are provided, and the coating layer comprises the following components (a) and (b). A development in which a mixture containing components is applied and cured, the coating layer has an uneven shape due to having aggregates, and the particle size of the aggregates is 0.2 μm or more and 2.0 μm or less. roller;
(A) A graft prepolymer having a branched chain composed of a silicone chain and any one main chain selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and having at least two or more hydroxyl groups.
(B) Polyisocyanate.

(2) The component (a) is obtained by reacting a one-terminal diol-modified silicone oil with any one compound selected from a polycarbonate polyol, a polyacrylate polyol, and a polyester polyol with a polyisocyanate. The developing roller according to (1).

(3) The developing roller according to (1) or (2), wherein the coating layer contains a filler and the particle size of the filler is 2.0 μm or more and 15 μm or less.

(4) The above-mentioned (1) to (3), wherein the molar ratio of the isocyanate group to the hydroxyl group in the component (a) and the component (b) is 5: 1 to 15: 1. Development roller.

(5) A developing apparatus including the developing roller according to any one of (1) to (4).

(6) An image forming apparatus comprising the developing roller according to any one of (1) to (4).

In the developing roller of the present invention, the coating layer has a branched chain composed of a silicone chain and any one main chain selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and has at least two or more hydroxyl groups. The coating layer is formed by applying and curing a mixture containing a graft prepolymer and a polyisocyanate having a particle size of 0.2 μm or more and 2.0 μm or less, so that the coating layer has an uneven shape. By having such a minute uneven shape in the coating layer, it is possible to obtain a developing roller having excellent toner releasability and satisfactorily suppressing the occurrence of filming, and a developing device and an image forming device provided with the developing roller. can.

It is a drawing which shows the developing roller of this invention. It is explanatory drawing which shows an example of the image forming apparatus which incorporates the semi-conductive sponge roller which shows one Example of this invention in the fixing apparatus. It is a drawing which shows the mode of the uneven shape of a coating layer. It is a drawing which shows the mode of the uneven shape of a coating layer.

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>
The developing roller 1 of the present invention includes a shaft body 2, an elastic layer 3 provided on the outer surface of the shaft body 2, and a coating layer 4 provided outside the elastic layer 3.

[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. It should be noted that such a shaft body 2 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 rod-shaped, tubular, 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 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 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 contains a cured product of a silicone rubber composition containing a conductivity-imparting agent. The silicone rubber composition is a composition capable of forming an elastic body containing silicone rubber by curing, and may contain, for example, a silicone polymer capable of forming silicone rubber by cross-linking. When the elastic layer 3 contains silicone rubber, it is possible to reduce the compression set and obtain the effect of excellent flexibility in a low temperature environment.

Examples of the silicone rubber include crosslinked products of organopolysiloxane such as dimethylpolysiloxane and diphenylpolysiloxane. Further, the silicone rubber may be a modified product of these.

The conductivity-imparting agent may be any component that can impart conductivity to the elastic layer 3. Examples of the conductivity-imparting agent include conductive powders such as metals, metal oxides, and conductive polymers, carbon black, ionic conductive agents, and surfactants.

Carbon black is particularly preferable as the conductivity-imparting agent. By blending carbon black with ether-modified silicone oil into the silicone composition, the effects on chargeability and charge decay rate are more pronounced. As the conductivity-imparting agent, one type may be used alone, or two or more types may be used in combination. For example, in the silicone rubber composition, only carbon black may be used as the conductivity-imparting agent, and carbon black and other conductivity-imparting agents may be used in combination.

The carbon black is not particularly limited, and for example, acetylene black, furnace black, channel black, ketjen black, thermal black and the like are preferably used. As the carbon black, one of these may be used alone, or two or more thereof may be used in combination.

The content of the conductivity-imparting agent in the silicone rubber composition is preferably 0.5% by mass or more and 20% by mass or less, and 1.0% by mass or more and 15% by mass or less, based on the total amount of the silicone composition. More preferably, it is more preferably 2.0% by mass or more and 10% by mass or less. By adjusting the content of the conductivity-imparting agent within the above range, the resistance value of the developing roller 1 is further stabilized, the printing performance is further improved, the compression set of the elastic layer 3 is reduced, and the developing roller is reduced. The durability of 1 is further improved.

The silicone rubber composition may further contain various additives other than the above. Examples of various additives include auxiliaries (chain extenders, cross-linking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, fillers, pigments, colorants, processing auxiliaries, and softeners. , Plasticizers, emulsifiers, heat resistance improvers, flame retardant improvers, acid receivers, thermal conductivity improvers, mold release agents, solvents and the like.

The method for curing the silicone rubber composition is not particularly limited, and a known curing method may be adopted. For example, the silicone rubber composition may be cured by adding a vulcanizing agent and heating, or the cross-linking agent contained in the silicone rubber composition may be reacted by heating to cure.

The silicone rubber composition may be, for example, an addition-curable mirable conductive silicone rubber composition, an addition-curable liquid conductive silicone rubber composition, or the like.

(Additional Curable Mirable Conductive Silicone Rubber Composition)
The addition-curable mirabable conductive silicone rubber composition includes, for example, (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C1) an ether-modified silicone oil having a reactive group. And, it may contain (C2) a conductivity-imparting agent.
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 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. 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 (A) The organopolysiloxane may be basically a linear diorganopolysiloxane, and may be partially branched. Further, (A) organopolysiloxane may be a mixture of two or more kinds having different molecular structures.

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

The blending amount of the ether-modified silicone oil having the (C1) reactive group is preferably 0.1 part by mass or more, preferably 0.2 part by mass or more, with respect to 100 parts by mass of the (A) organopolysiloxane. Is more preferable.

The blending amount of the (C2) 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 (C2) 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 (C2). 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, 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 contains, for example, (D) an organopolysiloxane having two or more alkenyl groups in the molecule and (E) two or more hydrogen atoms bonded to silicon atoms 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, and 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 A diphenylsiloxane / dimethylsiloxane copolymer, a copolymer _{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. Examples} thereof include a copolymer composed of a unit and (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. ..

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 preferably 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% by mass or more and 1000% by mass 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, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, etc. Examples thereof include heat resistance improvers, flame retardant improvers, acid acceptors, heat conductivity improvers, mold release agents, diluents, reactive diluents, solvents and the like.

Specific examples of the additive include dispersants such as small molecule 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 method of 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 the silicone rubber composition. Further, the elastic layer 3 may be formed by grinding or polishing an elastic body (cured product of a silicone rubber composition) formed on the shaft body 2.

[Coating layer]
The coating layer 4 is provided on the outermost surface of the developing roller 1. The coating layer 4 does not have to cover the entire outer peripheral surface of the elastic layer 3, and may cover the elastic layer 3 as long as there is no problem in the printing function. In order to improve the toner releasability of the developing roller 1 and prevent the occurrence of filming, it is necessary to adjust at least the characteristics of the coating layer 4. In the present invention, the coating layer 4 is cured by applying a mixture containing the following components (a) and (b). Further, the coating layer 4 is formed with agglomerates having a particle size of 0.2 μm or more and 2.0 μm or less by curing the mixture containing the above components, whereby the coating layer 4 is as shown in FIG. In addition, it has a minute uneven shape. When the coating layer 4 has such an uneven shape, it is possible to obtain a developing roller 1 which is excellent in toner releasability and in which the occurrence of filming is satisfactorily suppressed.
(A) A graft prepolymer having a branched chain composed of a silicone chain and any one main chain selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and having at least two or more hydroxyl groups (b). Polyisocyanate.

The coating layer 4 thus obtained is a so-called urethane coat layer. The above mixture is in a liquid state before being heat-cured. The thickness of the coating layer 4 is not particularly limited, and is preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 20 μm or less.

((A) Graft prepolymer)
The graft prepolymer of the component (a) has a branched chain composed of a silicone chain and any one main chain selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and has at least two or more hydroxyl groups. Have. Such a graft prepolymer can be obtained by reacting a one-terminal diol-modified silicone oil with any one compound selected from a polycarbonate polyol, a polyacrylate polyol, and a polyester polyol with a polyisocyanate. ..

(One-ended diol-modified silicone oil)
The one-terminal diol-modified silicone oil is a kind of so-called reactive silicone oil, has a property of polymerizing with an isocyanate compound, and has two hydroxyl groups bonded to one end of a silicone chain. .. Usually, by using one-terminal diol-modified silicone oil, a branched chain is introduced into polyurethane, and the fine roughness of the developing roller 1 can be improved.

Examples of the one-terminal diol-modified silicone oil include one-terminal modified silicone oil represented by the following general formula (1).

（１）

(1)

In the general formula (1), R, R ″, and R ″ are hydrocarbon groups, and the number of carbon atoms of the hydrocarbon group is preferably 1 or more and 20 or less. n represents an integer.

Among the one-terminal diol-modified silicone oils represented by the general formula (1), it is particularly preferable to use silicone oils in which n is an integer. In the general formula (1), the functional group bonded to the silicon atom is a hydrocarbon group, but a silicone oil in which this hydrocarbon group is substituted with a hydrogen atom may be used.

(Polycarbonate polyol)
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 a polyol and a 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.

(Polyacrylate polyol)
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. , And fumaric acid monoalkyl esters and fumaric acid dialkyl esters, α-olefins and copolymers with other unsaturated monomers and unsaturated polymers.

(Polyester polyol)
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.

The number average molecular weight of the above three types of polyols is preferably 100 or more and 14000 or less, more preferably 500 or more and 11000 or less, and 500 or more and 6000 or less from the viewpoint of improving the flexibility of the coating layer 4. Is even more preferable. In the present specification, the number average molecular weight and the number average molecular weight indicate the values converted to standard polystyrene by gel permeation chromatography (GPC).

In the present invention, in order to improve the toner releasability and effectively prevent filming while maintaining good development performance by adjusting the surface roughness of the coating layer 4, the graft prepolymer is used. The above-mentioned polyol compound used for preparation is preferably 200 parts by mass or more and 1000 parts by mass or less, and 400 parts by mass or more and 800 parts by mass or less with respect to 100 parts by mass of one-terminal diol-modified silicone oil. Is more preferable.

(Polyisocyanate)
Polyisocyanate is a compound having two or more isocyanate groups (-NCO). In the present invention, the polyisocyanate used for the preparation of the graft prepolymer is not particularly limited as long as it has reactivity with the reactive group introduced into the silicone oil, and is usually used for the preparation of polyurethane. Any polyisocyanate may be used. Examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, carbodiimide-modified polyisocyanates of these polyisocyanates, and isocyanurate-modified polyisocyanates thereof. As these polyisocyanates, one kind or two or more kinds can be used. The longer the molecular chain of an isocyanate compound, the more flexible polyurethane can be produced.

Examples of the aromatic polyisocyanate include 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), and 4,4'-diphenylmethane diisocyanate (4,4). '-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, trizine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), Examples thereof include 3,3'-dimethylbiphenyl-4,4'-diisocyanate.

Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornene diisocyanate methyl (NBDI), xylylene diisocyanate (XDI), and tetramethylxylene diisocyanate (TMXDI). ) Etc. can be mentioned.

Examples of the alicyclic polyisocyanate include transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6XDI (hydrogenated XDI), H12MDI (hydrogenated MDI), 4,4'-dicyclohexylmethane diisocyanate and the like. Can be mentioned.

In the present invention, the polyisocyanate used for preparing the graft prepolymer is preferably 20 parts by mass or more and 400 parts by mass or less, and 40 parts by mass or more and 200 parts by mass with respect to 100 parts by mass of one-terminal diol-modified silicone oil. More preferably, it is less than or equal to a part. By setting the amount of polyisocyanate used with respect to the one-terminal diol-modified silicone oil within the above range, the viscosity of the mixture for forming the coating layer 4 can be made suitable, and workability can be improved. The number average molecular weight of the graft prepolymer thus obtained is preferably 100 or more and 10,000 or less.

((B) Polyisocyanate)
As the polyisocyanate used as the component (b), the above-mentioned polyisocyanate can be used. The polyisocyanate used as the component (b) does not necessarily have to be the same as the polyisocyanate used for preparing the graft prepolymer described above.

In the present invention, the amount of the polyisocyanate of the component (b) used is preferably 5 parts by mass or more and 1000 parts by mass or less with respect to 100 parts by mass of the component (a), and is 10 parts by mass or more and 600 parts by mass or less. More preferably. By setting the amount of polyisocyanate used within the above range, the hardness of the formed coating layer 4 can be maintained within a suitable range.

Further, the molar ratio of the isocyanate group to the hydroxyl group in the components (a) and (b) is preferably 5: 1 to 15: 1, and more preferably 8: 1 to 12: 1. .. By adjusting the molar ratio of the isocyanate group to the hydroxyl group in the component (a) and the component (b) within the above range, it is possible to obtain an uneven shape capable of more effectively suppressing the occurrence of filming.

(Diluting solvent)
In the present invention, a diluting solvent can be used in addition to the above components (a) and (b). An aqueous solvent and an organic solvent can be used, and a low boiling point solvent and a high boiling point solvent can be used in combination depending on the required drying speed.

In the present invention, in the mixture for forming the coating layer 4, the solid content concentration is preferably in the range of 3% by mass or more and 50% by mass or less, and preferably in the range of 5% by mass or more and 30% by mass or less. Is more preferable. If the solid content concentration is low, liquid dripping is likely to occur during coating, and it takes time to dry. If the solid content concentration is high, the coating surface becomes rough and it becomes difficult to control the thickness.

As the diluting solvent, it is preferable to use an organic solvent such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), tetrahydrofuran (THF), acetone, ethyl acetate, butyl acetate, toluene, xylene, heptane, cyclohexanone, and isophoron.

(Filler)
The coating layer 4 preferably further contains a filler, and the particle size of the filler is preferably 2.0 μm or more and 15 μm or less, and more preferably 3.0 μm or more and 6.0 μm or less. When the coating layer 4 contains a filler having a particle size in the above range, uneven shapes having different sizes are formed as shown in FIG. 4, and the toner releasability is more effectively improved for filming. Occurrence can be suppressed. As the filler to be used, the same filler as the filler used for the elastic layer 3 can be used.

When the coating layer 4 contains a filler, the content of the filler is preferably 0.1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the resin component of the coating layer 4, for example, 1 mass. It is more preferable that the amount is 40 parts by mass or more.

(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. As the conductivity-imparting agent, the conductivity-imparting agent used for the elastic layer 3 described above can be used. 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 polymerization catalyst, and a dispersant.

The coating layer 4 can be formed by applying a mixture containing the components (a) and (b) on the elastic layer 3 and polymerizing the polyol component and the isocyanate component by heating or the like. The solvent used in the coating liquid is preferably a solvent capable of dissolving the polyol component and the polyisocyanate component, and may be, for example, ethyl acetate, butyl acetate or the like.

[Primer layer and adhesive layer]
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, particularly the adhesive layer and the primer layer provided between the elastic layer 3 and the coating layer 4 have the electrical characteristics as the developing roller 1 by adjusting the electrical characteristics thereof. With this, the developing performance of the developing roller 1 as a developing roller can be satisfactorily adjusted.

(Primer layer)
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.

<Developer and image forming device>
The developing roller 1 according to the present embodiment can be suitably used as a developing agent carrier in a developing device and an image forming device. 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 is a tandem type color image forming apparatus in which a plurality of image carriers 11B, 11C, 11M and 11Y mounted on the developing units B, C, M and Y of each color are arranged in series on the transfer transfer belt 6. The developing units B, C, M and Y are arranged in series on the 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 and the developing agent of the present invention 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, that is, as a developing roller. Specifically, the developing apparatus 20B includes a housing 21B accommodating a one-component non-magnetic developer 22B, a developing agent carrier 23B for supplying the developing agent 22B to the image carrier 11B, for example, a developing roller, and a developing agent 22B. It is provided with a developer amount adjusting means 24B for adjusting the thickness of the developer, for example, a blade. 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 so-called "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 pressed against 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 so-called "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 support roller in a housing having an opening 35 through which the recording body 16 is passed. An endless belt 36 wound around 33 and a pressure roller 32 arranged to face the fixing roller 31 are provided so that the fixing roller 31 and the pressure roller 32 come into contact with each other or are in pressure contact with each other via the endless belt 36. It is a pressure heat fixing device that is rotatably supported. 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 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 each developing unit, a one-component non-magnetic black developer 22B, a cyan developer 22C, a magenta developer 22M and a yellow developer 22Y are housed.

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 16B. 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.

This developing apparatus 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. In addition, this image forming apparatus can form a high-density and high-quality image for a long period of time.

The developing apparatus and 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 10 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. good. Further, the image forming apparatus in which the developing roller of the present invention is arranged is not limited to a tandem type color image forming apparatus in which a plurality of image carriers provided 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. The developer used in the image forming apparatus 10 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. Also, it may be a two-component magnetic developer.

The image forming apparatus 10 is a so-called "contact type image forming apparatus", but in the present invention, the image forming apparatus is arranged with a gap so that the surface of the developer carrier does not come into contact with the surface of the image carrier. It may be a so-called "non-contact image forming apparatus".

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 to which such changes or improvements have been made can 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)
The shaft body (made by SUM22, diameter 10 mm, length 275 mm) subjected to electroless nickel plating is washed with ethanol, and a silicone-based primer (trade name "Primer No. 16", manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the surface thereof. It 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.

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.} , Japan Aerosil) 1 part by mass, average particle size 6 μm, bulk density 0.25 g / cm ³ diatomaceous earth (trade name "Opreite W-3005S", made by Central Silica) 40 parts by mass, and acetylene black (Product name "Denka Black HS-100", manufactured by Denka) 5 parts by mass 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 as a cross-linking agent, 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. , 0.1 part by mass of ethynylcyclohexanol and 0.1 part by mass of platinum catalyst (Pt concentration 1%) were added as a reaction control agent, and the mixture was stirred for 30 minutes, defoamed and kneaded, and then subjected to addition curing type liquid conductive silicone rubber composition. Was prepared.

An elastic body made of a rubber material was molded on the outer peripheral surface of the shaft by liquid injection molding using the prepared addition-curable liquid conductive silicone rubber composition. In injection molding, the addition-curable liquid conductive silicone rubber composition was heated at 130 ° C. for 10 minutes to be cured. This elastic body was polished to form an elastic layer having an outer diameter of 16 mm.

Next, a resin composition for forming a coating layer was prepared as follows.
That is, 16.7 parts by mass of one-terminal diol-modified silicone oil, 100 parts by mass of a polycarbonate diol compound, and 17.1 parts by mass of hexamethylene diisocyanate (trade name "Duranate TPA-100", manufactured by Asahi Kasei) as components (a). 300 parts of the thinner was mixed and reacted to obtain a graft prepolymer having a number average molecular weight of 1600. 8 parts by mass of the graft prepolymer thus obtained, 13 parts by mass of hexamethylene diisocyanate (trade name "Duranate TSE-100", manufactured by Asahi Kasei) as a component (b), and 0.03 of dibutyltin dilaurate (manufactured by Showa Kagaku). A resin composition was obtained by mixing 30 parts by mass and 30 parts by mass of thinner.

The prepared resin composition 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 5 μm or more and 15 μm or less.

The developing roller A-1 of Example 1 was produced by the above method. The surface uneven shape (particle size of the agglomerates) of the produced developing roller A-1 was observed using a laser microscope.

Next, an image forming apparatus C610dn2 (model number, manufactured by Oki Data Corporation) was prepared, and the developing roller of this image forming apparatus was replaced with the developing roller A-1 produced to obtain the image forming apparatus of Example 1. The obtained image forming apparatus was evaluated for toner filming by the following method.

<Evaluation of toner filming>
Using the image forming apparatus equipped with the produced developing roller, a 0.3% duty image was printed on 8000 sheets of A4 paper under the conditions of a temperature of 23 ° C. and a humidity of 55% RH. After printing, the amount of toner adhering to the developing roller was measured. The case where the amount of adhesion was less than 0.5 mg was evaluated as A, the case where the amount was 0.5 mg or more and 1.0 mg or less was evaluated as B, and the case where the amount was more than 1.0 mg was evaluated as C. The evaluation results are shown in Table 1.

(Example 2)
A coating layer was formed on the same elastic layer as in Example 1 by the following method. That is, 16.7 parts by mass of one-terminal diol-modified silicone oil, 100 parts by mass of a polycarbonate diol compound, and 17.1 parts by mass of hexamethylene diisocyanate (trade name "Duranate TPA-100", manufactured by Asahi Kasei) as components (a). 300 parts of the thinner was mixed and reacted to obtain a graft prepolymer having a number average molecular weight of 1600. 8 parts by mass of the graft prepolymer thus obtained, 13 parts by mass of hexamethylene diisocyanate (trade name "Duranate TSE-100", manufactured by Asahi Kasei) as a component (b), and dibutyltin dilaurate (manufactured by Showa Kagaku) as other components. A resin composition was obtained by mixing 0.03 parts by mass, 1 part by mass of small-diameter silica (average particle size 4.4 μm, trade name “ACEMATT OK-607”, manufactured by Evonik Degussa), and 30 parts by mass of thinner.

The developing roller A-2 of Example 2 was obtained by the above method. For the developing roller A-2, an image forming apparatus was manufactured and each characteristic was evaluated by the same method as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
In forming the coating layer, the component (a) of Example 1 was the same as that of Example 1 except that the one-terminal diol-modified silicone oil was not used and the small-diameter silica used in Example 2 was used. To prepare a developing roller. With respect to the obtained developing roller B-1 of Comparative Example 1, an image forming apparatus was manufactured and each characteristic was evaluated by the same method as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A developing roller was produced in the same manner as in Example 1 except that a double-ended diol-modified silicone oil was used instead of the one-terminal diol-modified silicone oil for the component (a) of Example 1 when forming the coating layer. bottom. With respect to the obtained developing roller B-2 of Comparative Example 3, an image forming apparatus was manufactured and each characteristic was evaluated by the same method as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
When forming the coating layer, a developing roller was produced in the same manner as in Example 2 except that the component (a) of Example 2 used both-terminal diol-modified silicone oil instead of the one-terminal diol-modified silicone oil. .. With respect to the obtained developing roller B-3 of Comparative Example 3, an image forming apparatus was manufactured and each characteristic was evaluated by the same method as in Example 1. The results are shown in Table 1.

<Evaluation>
When the surface shape of the produced developing roller was observed using a laser microscope, aggregates of 0.2 μm or more and 2 μm or less were observed in Examples 1 and 2, and further, in Example 2, the size was increased by small-diameter silica. Different uneven shapes were observed. On the other hand, in Comparative Examples 1 to 3, unlike Examples 1 and 2, no aggregate was observed.
Further, in the developing rollers of Examples 1 and 2, the occurrence of filming was satisfactorily suppressed as compared with the developing rollers of Comparative Examples 1 to 3.

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 20 Developer 21B, 21C, 21M, 21Y, 34 Housing 22B, 22C, 22M, 22Y Developer 23B, 23C, 23M, 23Y Development Agent carrier 24B, 24C, 24M, 24Y Developer regulating member 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 developing unit

Claims (4)

A shaft body, an elastic layer provided on the outer peripheral surface of the shaft body, and a coating layer provided outside the elastic layer are provided.
The coating layer is obtained by applying and curing a mixture containing the following components (a) and (b).
It said coating layer has an uneven shape by having an aggregate state, and are particle size 0.2μm or 2.0μm below the aggregate,
A developing roller in which the coating layer contains a filler and the particle size of the filler is 2.0 μm or more and 15 μm or less.
(A) A branched chain composed of a silicone chain obtained by reacting a one-terminal diol-modified silicone oil with any one compound selected from a polycarbonate polyol, a polyacrylate polyol, and a polyester polyol with a polyisocyanate. , A graft prepolymer having a main chain of any one selected from a polycarbonate chain, a polyacrylate chain, and a polyester chain, and having at least two or more hydroxyl groups.
(B) Polyisocyanate. Wherein in component (a) and the component (b), the molar ratio of isocyanate groups to hydroxyl groups is 5: 1 to 15: 1, a developing roller according to claim 1. A developing apparatus comprising the developing roller according to claim 1 or 2. An image forming apparatus comprising the developing roller according to claim 1 or 2.

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