JP7052973B2 - Developing rollers, developing equipment and image forming equipment - Google Patents

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 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 is performed by the frictional heat with the blade or the like. It is believed that this is caused by the melting of the agent. In a developing roller, there is a demand for a developing roller that suppresses the occurrence of filming as much as possible and thereby stabilizes durable printing performance.

For example, Patent Document 1 describes a conductive roller containing an ionic liquid, which makes it difficult for a developer to adhere to the surface for a long period of time. Further, Patent Document 2 discloses a reactive fluorine-containing copolymer useful as a surface modifier for imparting anti-fingerprint property and surface smoothness to the surface of a resin, film, fiber or the like. Furthermore, in Patent Document 3, in order to maintain toner releasability and abrasion resistance, a perfluoropolyether is contained in the outermost layer, and the ratio of fluorine atom / carbon atom on the surface is 0.1 or more and 0.4. The following electrophotographic members are disclosed.

Japanese Unexamined Patent Publication No. 2011-221424 JP-A-2015-120852 JP-A-2015-28613

However, the developing roller or the electrophotographic member described in the above patent document cannot suppress the occurrence of filming to the extent that it can sufficiently correspond to the performance of the image forming apparatus required in recent years, and is not satisfactory in terms of durable printing performance. I didn't.
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 an elastic layer formed on the outer peripheral surface of the shaft body and a coating layer formed on the outer peripheral surface of the elastic layer, and the coating layer has 20 fluorine atoms on the surface. The atomic% or more and 60 atomic% or less, and the arithmetic mean roughness Ra is 0.4 or more and 1.5.
Here, the "content of fluorine atom on the surface" means the value measured by ESCA shown in Examples described later.

In the developing roller of the present invention, the ratio of the number of fluorine atoms to the number of carbon atoms contained in the coating layer (fluorine atom / carbon atom) is preferably more than 0.4 and 1.0 or less.
Here, the ratio of the number of fluorine atoms to the number of carbon atoms contained in the coating layer means the value measured by the measuring method in the examples described later.

In the developing roller of the present invention, the coating layer is preferably obtained by heating and curing the coating layer resin composition, and the content of fluorine atoms in the coating layer resin composition is preferably less than 5% by mass.

The resin composition for a coating layer is a (meth) acrylate copolymer containing (a) a polyol, (b) an isocyanate, (c) a hydroxyl group and a fluorine atom of 1% by mass or more and 10% by mass or less, and (d) a surface. Those containing a roughness material and (e) an ion conductive material are preferable.

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 is a developing roller including an elastic layer 3 formed on the outer peripheral surface of the shaft body 2 and a coating layer 4 formed on the outer peripheral surface of the elastic layer 3. The coating layer 4 has 20 atomic% or more and 60 atomic% or less of fluorine atoms on the surface, and has an arithmetic mean roughness Ra of 0.4 or more and 1.5 or less.
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 made 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 a treatment such as a cleaning treatment, a degreasing treatment, and a 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 (diameter of the circumscribed circle) of the shaft body 2 is preferably 4 mm or more and 14 mm or less, and more preferably 6 mm or more and 10 mm or less.

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

Examples of the rubber in the rubber composition include silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, and chloroprene. Examples thereof include rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, and fluororubber. Silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber can reduce compression set and is excellent in flexibility in a low temperature environment, and further has heat resistance and charging characteristics. It is particularly preferable in that it is excellent in such things as. Examples of the silicone rubber include crosslinked products of organopolysiloxane such as dimethylpolysiloxane and diphenylpolysiloxane.
Examples of the silicone rubber composition include an addition-curable mirrorable conductive silicone rubber composition and an addition-curable liquid conductive silicone rubber composition.

-Additional Curable Mirable 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. Further, R ¹ indicates 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 trill group, and an aralkyl group such as a β-phenylpropyl group. Further, R ¹ may be a group in which a part or all of the hydrogen atoms of these hydrocarbon groups are substituted with a substituent. The substituent may be, for example, a halogen atom, a cyano group, or the like. Examples of the hydrocarbon group having a substituent include a chloromethyl group, a trifluoropropyl group, 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.

(A) The organopolysiloxane preferably has two or more alkenyl groups in the molecule. (A) The organopolysiloxane preferably has an alkenyl group of 0.001 mol% or more and 5 mol% or less (more preferably 0.01 mol% or more and 0.5 mol% or less) of ^R1 . (A) The vinyl group is particularly preferable as the alkenyl group contained in the organopolysiloxane.

(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 kinematic viscosity of (A) organopolysiloxane at 25 ° C. is preferably 100 cSt or more, and more preferably 100,000 cSt or more and 10,000,000 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 the 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 methacryoxy 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.A. M. Examples thereof include the product 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 the median diameter using a particle size distribution measuring device by a laser light diffraction method.

Examples of the conductivity-imparting agent include carbs, metals, genus oxides, metal compounds, conductive polymers, ionic liquids and the like. 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. Further, 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). Examples of the additive include auxiliary agents (chain extenders, cross-linking agents, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, etc. Examples thereof include emulsifiers, ion conductive agents, heat resistance improvers, flame retardant improvers, acid receiving agents, heat conductivity improvers, mold release agents, solvents and the like.

Specific examples of the additive include (A) both-terminal silanol group encapsulation such as (A) dimethylsiloxane oil having a lower degree of polymerization than organopolysiloxane, polyether-modified silicone oil, silanol, diphenylsilanediol, and α, ω-dimethylsiloxanediol. 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 silicon atoms in the molecule. It may contain (F) a filler, (G) a conductivity-imparting agent, and (H) an addition reaction catalyst.

As the (D) organopolysiloxane, 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. Further, ^R4 indicates a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. However, at least two of ^R4 in one molecule are alkenyl groups. 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. Further, it is preferable that at least two of R ^4s in one molecule are alkenyl groups, and the other R ^4s are alkyl groups. The alkenyl group is preferably a vinyl group, and the alkyl group is preferably a methyl group. Further, for example, 90% or more of R ⁴ may be an alkyl group (preferably a methyl group). (D) The content of the alkenyl group in the 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 ⁻ . It is more preferably ⁶ mol / g or more and 1.0 × 10 ^-3 mol / g or less.

(D) The organopolysiloxane 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. Further, 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 (E) organohydrogenpolysiloxane, 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. Further, R5 indicates 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 (E) organohydrogenpolysiloxane in one molecule 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 double-ended trimethylsiloxy group-blocked methylhydrogenpolysiloxane, a double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, and a double-ended dimethylhydrogensiloxy group-blocked. 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, and (CH ₃ ) ₂ HSiO _1/2 unit 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 is reduced, the volume resistivity is stable over time, and sufficient roller durability is obtained.

(F) The average particle size of the filler 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 (F) filler 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 0.1 g / cm ³ or more and 0.5 g / cm ³ or less, and more preferably 0.15 g / cm ³ or more and 0.45 g / cm ³ or less. .. (F) By adjusting the bulk density of the filler to 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 crushed pearlite foam 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 with respect to 100 parts by mass of (D) organopolysiloxane, and more preferably 10 parts by mass or more and 80 parts by mass or less. ..

Examples of the conductivity-imparting agent include carbon, metal, metal oxide, metal compound, conductive polymer, ionic liquid and the like. 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. It is more preferable to have.

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, second platinum chloride, platinum chloride acid, reaction products of platinum chloride acid and monovalent alcohol, and complexes of platinum chloride acid and olefins). , Platinum bisacetoacetate, etc.), palladium-based catalysts, rhodium-based catalysts, etc.

(H) The blending amount of the addition reaction catalyst may be the amount of the catalyst. For example, in the blending amount of (H) addition reaction catalyst, 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 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. It is not limited. 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 some cases, 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 carried out. In the case of the addition-curing type mirabable 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.

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, ion conductives, pigments, colorants, processing aids, softeners, plasticizers. Examples thereof include agents, emulsifiers, heat resistance improvers, flame retardant improvers, acid receiving agents, thermal conductivity improvers, mold release agents, diluents, reactive diluents, solvents and the like.

Specific examples of the additive include dispersants such as small molecule siloxane esters, polyether-modified silicone oils, silanols, and phenylsilanediol. Further, heat resistance improving agents 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 axis 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.

-Other ingredients-
The 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, pigments, colorants, processing aids, softeners, and plasticizers. , Emulsifier, heat resistance improver, flame retardancy improver, acid receiving agent, heat conductivity improver, mold release agent, solvent and the like.

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

(A) Polyol The polyol may be any of various polyols usually used in the preparation of 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, copolymerized polyols of tetrahydrofuran and alkylene oxide, and various modified products thereof or their respective. Examples include mixtures.

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 oligomers 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 diallyl 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-butanetriol.
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 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 dimerate), xylene diisocyanate, naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI), Examples thereof include trizine diisocyanate (TODI) and metaphenylenedi isocyanate.
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.
Derivatives include polyisocyanate polynuclears, urethane modified products (including urethane prepolymers) modified with polyols, dimers by uretidine formation, isocyanurate modified products, carbodiimide modified products, uretonimine modified products, alohanate modified products, etc. Examples include urea modified products and bullet modified products. 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 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.

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

(C) (Meta) acrylate copolymer containing a hydroxyl group and a fluorine atom of 1% by mass or more and 10% by mass or less A (meth) acrylate common weight containing a hydroxyl group and a fluorine atom of 1% by mass or more and 10% by mass or less. The coalescence (hereinafter, may be simply referred to as (c) (meth) acrylate copolymer) has at least a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms in the copolymer. .. Such a copolymer is composed of at least a fluorine-containing (meth) acrylate monomer (c-1) and a hydroxyl group-containing (meth) acrylate monomer (c-2).

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

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

Examples of the divalent group having 2 to 50 carbon atoms represented by ^R2 include the following groups.

-(CH ₂ ) _n1- (n1 = 2-50)
-XY- (CH ₂ ) _n2- (n2 = 2-43)
-X- (CH ₂ ) _n3- (n3 = 1-44)
-CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n4- (n4 = 1 to 24)
-XCO (OCH ₂ CH ₂ ) n5- ( _n5 = 1-21)
(In the formula, X may have 1 to 3 substituents selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. Phenylene, biphenylene or naphthylene. Y indicates -O-CO-, -CO-O-, -CONH- or NHCO-).

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

Specific examples of the particularly preferable divalent group having 2 to 50 carbon atoms represented by R ² include a divalent group having the following structure.

-(CH ₂ ) _n1- (n1 = 2-10)
-C ₆ H ₄ OCO (CH ₂ ) _n2- (n2 = 2-10)
-C ₆ H ₄ (CH ₂ ) _n3- (n3 = 1-10)
-CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n4- (n4 = 1 to 10)
-C ₆ H ₄ CO (OCH ₂ CH ₂ ) _n5- (n5 = 1 to 10)

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

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

In the formula, R ³ is an H or methyl group. ^R4 is a divalent group having 2 to 50 carbon atoms, preferably 2 to 10 carbon atoms, or an alkylene oxide group having a repeating unit of 2 to 20.

In the general formula (c-2), examples of the divalent group having 2 to 50 carbon atoms represented by R ⁴ include the divalent group exemplified by R ² . The number of carbon atoms of this divalent group is preferably 2 to 10.

The repeating unit represented by ^R4 is more preferably an ethylene oxide group having 2 to 20 alkylene oxide groups, a polyalkylene oxide group having a propylene oxide group or the like as a repeating unit. In the polyalkylene oxide group, the repeating unit of the alkylene oxide is preferably 2 to 20.

Specific preferred ^R4s include the following groups.

-(CH ₂ ) _n6- (n6 = 2-10)
-(CH ₂ CH ₂ O) _n7 CH ₂ CH _2- (n7 = 1 to 20)
-(CHCH ₃ CH ₂ O) _n8 CHCH ₃ CH _2- (n8 = 1-10)

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

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

^In the formula, R5 is an H or a methyl group. ^R6 is an aromatic hydrocarbon group that may be substituted. n is an integer from 0 to 4.

In the general formula (c-3), examples of the aromatic hydrocarbon group represented by R ⁶ have 6 carbon atoms such as a phenyl group, a naphthyl group, a toluyl group, a xylyl group, an anthranyl group, a phenanthryl group, and a biphenyl group. Included are up to 15 aromatic hydrocarbon groups. Examples of the substituent of the substituted aromatic hydrocarbon group include methyl, ethyl, propyl, butyl, methoxy, ethoxy, methylenedioxy, chlorine atom, NO ₂ , CN, NHCOCH ₃ and the like. The substituent may be contained in the aromatic hydrocarbon group in an amount of 1 to 3, preferably 1 to 2.

Benzyl methacrylate is particularly preferable as the (meth) acrylate compound represented by the general formula (c-3).

The compound represented by the general formula (c-3) can be produced by a known method or can be obtained as a commercially available product. Examples of commercially available products include Light Ester BZ (Kyoeisha Chemical Co., Ltd.) and Funkrill FA-BZM (Hitachi Kasei Co., Ltd.).

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

In the formula, R ⁷ is an H or methyl group. R8 is H or an aliphatic hydrocarbon group having ¹ to 50 carbon atoms.

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

Preferred ^R8s include cyclic structures such as an alkyl group, a cyclohexyl group, a dicyclopentenyl group, and a dicyclopentenyl group. Particularly preferable ^R8 is an aliphatic hydrocarbon group having the following structure.

-(CH ₂ ) _n6 CH ₃ (n6 = 1 to 30)

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

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

(D) 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 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 resin composition for the coating layer 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 resin composition for the coating layer. Is more preferable.

(E) Ion Conductive Material Examples of the ion conductive substance include sodium perchlorate, lithium perchlorate, calcium perchlorate, lithium chloride, lithium bis (trifluoromethanesulfonyl) imide, and potassium bis (trifluoromethanesulfonyl) imide. Inorganic ionic conductive substances such as, etc. may be mentioned. The content of the ionic conductive material in the resin composition for the coating layer is preferably 0.01 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the resin composition for the coating layer. Is more preferable.

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.

The coating layer 4 is coated with a resin composition for a coating layer on the elastic layer 3 and contains (a) a polyol component and (c) a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms by heating or the like (a). The meta) acrylate copolymer component and (b) isocyanate component are polymerized and cured. 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 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.

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 still in high humidity, 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 thus formed, the precursor forming the resin and the ionic conductive material may react and become one, or a complex may be formed. Further, the ionic conductive material may not react with the precursor forming the resin and may be dispersed in the resin.

The coating layer in the present invention is formed by heat-curing the resin composition for the coating layer, and the content of fluorine atoms in the resin composition for the coating layer is preferably less than 5% by mass. It is more preferably 0.1% by mass or more and 5% by mass or less, further preferably 0.2% by mass or more and 4.5% by mass or less, and most preferably 0.2% by mass or more and 4% by mass or less. When the content is 0.2% by mass or more, the fluorine element is transferred to the surface of the coating layer, so that the oil repellency of the surface of the coating layer is improved and filming can be satisfactorily prevented. If a large amount of a compound containing a fluorine atom (for example, a fluorine-based surfactant or the like) is added in order to improve the oil repellency, the conductivity is lowered, so that the content of the conductive filler must be increased. Further, when the content of the conductive filler is increased, the resin becomes hard, so that the wear resistance of the coating layer is lowered, the durable printing performance is lowered, and the cost is raised. Further, when the conductivity-imparting agent is an ionic conductive agent, it is blended in a large amount, which causes a problem of cost increase and bleeding. However, by setting the content of fluorine atoms as described above, it is not necessary to increase the conductive filler and the coating layer can be softened, so that the durability of the coating layer is improved and the developing roller having excellent durable printing performance can be obtained. Obtainable.

The coating layer includes (a) a polyol, (b) an isocyanate, (c) a (c) hydroxyl group and a (meth) acrylate copolymer containing 1% by mass or more and 10% by mass or less of a fluorine atom, and (d) a surface roughness material. And (e) The resin composition for a coating layer containing an ionic conductive material can be heat-cured to form.
Since the coating layer produced by the resin composition for a coating layer in the present invention contains a (meth) acrylate copolymer containing a hydroxyl group and a fluorine atom of 1% by mass or more and 10% by mass or less, the fluorine atom is a resin. It is unevenly distributed near the surface of the coating layer in a state of being taken in as a part of. Therefore, since fluorine atoms are present on the surface of the coating layer of the present invention for a long period of time, the developer melted by the operation of the image forming apparatus hardly adheres to the coating layer, and the amount of the developer adhering to the coating layer is remarkably increased. It can be reduced and a high-quality image can be provided.

-Content of fluorine atoms on the surface of the coating layer-
The coating layer of the developing roller of the present invention has 20 atomic% or more and 60 atomic% or less of fluorine atoms on the surface.
The "content of fluorine atoms on the surface of the coating layer" is a value measured by the measuring method shown in Examples described later.

-Arithmetic surface roughness Ra of the coating layer-
The coating layer of the developing roller of the present invention has an arithmetic surface roughness Ra of 0.4 or more and 1.5. The arithmetic surface roughness Ra is more preferably 0.6 or more and 1.3 or less. When the arithmetic surface roughness Ra is 0.4 or more, the carrying power of the developer can be increased. When the arithmetic surface roughness Ra is 1.5 or less, the toner does not remain on the unevenness of the surface of the coating layer, so that filming can be satisfactorily prevented.
The arithmetic surface roughness Ra is a value obtained by extracting a part of the roughness curve measured by the roughness meter with a reference length and calculating the unevenness state of the section by an average value.

-Ratio of the number of fluorine atoms to the number of carbon atoms contained in the coating layer (fluorine atom / carbon atom)-(hereinafter, simply referred to as fluorine atom / carbon atom)
The fluorine atom / carbon atom in the coating layer of the developing roller of the present invention is more than 0.4 and 1.0 or less. The fluorine atom / carbon atom in the coating layer of the developing roller of the present invention is more preferably 0.6 or more and 0.9 or less. Since the fluorine atom / carbon atom is more than 0.4, it has sufficient oil repellency to prevent the developer from adhering, so that the releasability of the developer can be improved and the filming can be performed. Can be satisfactorily prevented. Further, since the hardness of the coating layer is not too large when the fluorine atom / carbon atom is 1.0 or less, it is possible to prevent the coating layer from being worn and improve the durable printing performance. ..
The ratio of the number of fluorine atoms to the number of carbon atoms contained in the coating layer (fluorine atom / carbon atom) is a value measured by the measuring method shown in Examples described later.

(Other configurations)
The developing roller 1 of the present invention may include an intermediate layer such as an adhesive layer or a primer layer between the shaft body 2 and the elastic layer 3 and between the elastic layer 3 and the coating layer 4. Here, among these intermediate layers, 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 development performance of the developing roller 1 can be satisfactorily adjusted.

As the primer layer, a primer layer usually used as a primer layer of a developing roller can be used. For example, a material having a resistance value electrostatically conductive may be added to an existing primer, or an adhesive may be used. However, by using a metal-based primer that is electrostatically conductive, the development performance of the developing roller 1 can be maintained satisfactorily.

[Developing equipment and image forming equipment]
The developing roller 1 of the present invention can be suitably used as a developer 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 provided with 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 the above, and 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 photosensitive member (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 accommodating a one-component non-magnetic developer 22B, a developing agent carrier 23B for supplying the developing agent 22B to the image carrier 11B, and a developing agent carrier 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 developing agent amount adjusting means 24B is in contact with or pressed against the outer peripheral surface of the developing agent 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 the 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 "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-welded to each other via the endless belt 36. It is a pressure heat fixing device that is rotatably supported so as to be. 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 developers 22B, 22C, 22M and 22Y used in the image forming apparatus 10 may be a dry developer or a wet developer as long as they can be charged by friction, and may be a non-magnetic developer or magnetic developer. 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 in the developing unit B, the cyan image, the magenta image, and the yellow image are superimposed on the recording body 16 in which the electrostatic latent image is visualized as a black image by the developing units C, M, and Y, respectively. A color image is visualized. Next, 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 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 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 type 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 may be used. Further, the developer used in the image forming apparatus is a one-component non-magnetic developer, but in the present invention, it may be a one-component magnetic developer or a two-component non-magnetic developer. Alternatively, it may be a two-component magnetic developer.

The image forming apparatus is a contact type image forming apparatus which is arranged by contacting or pressing against an image carrier, a developer supply roller, a blade, or the like. 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 with reference to 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. It is also 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 a silicone-based primer (trade name "Primer No. 16", manufactured by Shin-Etsu Chemical Co., Ltd.) is used on the surface thereof. ) 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) having 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 diameter 6 μm, bulk density 0.25 g / cm ³ diatomaceous soil (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. Returning this to the planetary mixer again, methylhydrogenpolysiloxane having Si—H groups at both ends and side chains (polymerization degree 17, Si—H amount 0.0060 mol / g) 2.1 parts by mass, ethynylcyclohexanol 0.1 part by mass and 0.1 part by mass of a platinum-based catalyst (Pt concentration 1% by mass) were added, and the mixture was stirred for 30 minutes for defoaming and kneading 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.
The total content of (a) polyol and (b) isocyanate in the resin composition for the coating layer, (c) hydroxyl group and (meth) acrylate common weight containing 1% by mass or more and 10% by mass or less of fluorine atoms. Table 1 shows the contents (parts by mass) of the coalescence, (d) the surface roughness material, and (e) the ionic conductive material.

-Resin composition for coating layer-
(A) Acrylic polyol (UH-2041 manufactured by Toa Synthetic Co., Ltd.) 20 parts by mass (b) Isocyanate (hexamethylene diisocyanate) 25 parts by mass (c) Contains a hydroxyl group and 1% by mass or more and 10% by mass or less of fluorine atoms. (Meta) Acrylate copolymer 0.5 parts by mass (d) Surface roughness material (silica) ACEMATT412 Made by Ebonic Japan Co., Ltd.
3 parts by mass (e) Ion conductive material (potassium bis (trifluoromethanesulfonyl) imide, trade name "EF-N112", manufactured by Mitsubishi Materials Electronics Co., Ltd.)
0.2 parts by mass The molar ratio of polyisocyanate to acrylic polyol [NCO / OH] = 1.1 / 1.

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

[Example 2]
(C) The same as in Example 1 except that the (meth) acrylate copolymer containing a hydroxyl group and a fluorine atom containing 1% by mass or more and 10% by mass or less was changed to 0.25% by mass and silica was changed to 1.5 parts by mass. Similarly, a resin composition for a coating layer was prepared to form a coating layer.

[Example 3]
(C) The same as in Example 1 except that the (meth) acrylate copolymer containing a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom was changed to 1 part by mass and silica was changed to 4 parts by mass. A resin composition for a coating layer was prepared, and a coating layer was formed.

[Example 4]
(A) A resin composition for a coating layer was prepared in the same manner as in Example 1 except that the acrylic polyol was 16 parts by mass and the acrylic copolymer fluororesin "Defensa TR-101 was added by 4 parts by mass", and the coating layer was prepared. Formed.

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

[Comparative Example 2]
Example 1 except that the (meth) acrylate copolymer containing (c) a hydroxyl group of Example 4 and a fluorine atom containing 1% by mass or more and 10% by mass or less was not added and the silica was changed to 5 parts by mass. A resin composition for a coating layer was prepared in the same manner as in the above, and a coating layer was formed.

[Comparative Example 3]
The resin composition for a coating layer is the same as in Example 1 except that (c) a (meth) acrylate copolymer containing a hydroxyl group and a fluorine atom containing 1% by mass or more and 10% by mass or less is replaced with 5 parts by mass. Was prepared to form a coating layer.

[evaluation]

Next, 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 the 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.

(Content of fluorine atoms on the surface of the coating layer)
The content of fluorine atoms on the surface of the coating layer is determined by cutting out a sample having a measurable size after forming the coating layer, and using the formed sample as an ESCA (Electron Spectroscopic for Chemical Analysis, trade name "ESCA-1000", Shimadzu Corporation) measured the content of fluorine atoms at a depth of 1 to 10 nm from the surface of the coating layer under the following measurement conditions.
X-ray gun acceleration voltage: 10kV
X-ray gun emission current: 20mA
X-ray diameter: 1 mmφ

(Ratio of the number of fluorine atoms to the number of carbon atoms contained in the surface of the coating layer (fluorine atom / carbon atom))
The ratio of the number of fluorine atoms, carbon atoms, oxygen atoms, and nitrogen atoms was measured on the surface of the coating layer by the above ESCA, and the ratio of the number of fluorine atoms / carbon atoms was determined. The measurement conditions are the same as above.

(Content of Fluorine Atoms in Resin Composition for Coating Layer)
Cut out the resin composition for the coating layer, burn and absorb 0.01 g with the sample combustion device AQF-2100H (Mitsubishi Chemical Analytech Co., Ltd.), analyze the absorbed liquid with an ion chromatograph (manufactured by Shimadzu Corporation), and perform fluorine. Content was determined.

(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 is sucked under the conditions of temperature 23 ° C. and humidity 55% RH, 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 is passed 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, respectively, manufactured by X-Rite. The print density of the solid image was measured using a 508 spectroscopic densitometer.
-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)
The conditions of temperature 23 ° C., humidity 55% RH, temperature 30 ° C., humidity 80% RH, temperature 10 ° C., humidity 20% RH are changed in a cycle to perform a predetermined printing pattern on 10,000 sheets (double-sided printing). The next day, three solid images were printed, and the print density of the solid images was measured using a 508 spectroscopic densitometer manufactured by X-Rite. Specifically, 1.4 or more was designated as A, 1.2 or more and less than 1.4 was designated as B, and 1.0 or more and less than 1.2 was designated as C.
-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.

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 34 Housing 35 Opening 36 Endless belt 41 Cassette 42 Support roller B, C, M, Y Development unit

Claims (5)

A developing roller including an elastic layer formed on the outer peripheral surface of the shaft body and a coating layer formed on the outer peripheral surface of the elastic layer.
The coating layer has 20 atomic% or more and 60 atomic% or less of fluorine atoms on the surface, and has an arithmetic mean roughness Ra of 0.4 or more and 1.5 or less.
A developing roller in which the ratio of the number of fluorine atoms (fluorine atom / carbon atom) to the number of carbon atoms contained in the surface of the coating layer is more than 0.4 and 1.0 or less . The developing roller according to claim 1, wherein the coating layer is obtained by heating and curing the coating layer resin composition, and the content of fluorine atoms in the coating layer resin composition is less than 5% by mass. The resin composition for a coating layer is a (meth) acrylate copolymer containing (a) a polyol, (b) an isocyanate, (c) a hydroxyl group and 1% by mass or more and 10% by mass or less of a fluorine atom, (d). The developing roller according to claim 2 , which contains a surface roughness material and (e) an ion conductive material. A developing apparatus including the developing roller according to any one of claims 1 to 3 . An image forming apparatus comprising the developing roller according to any one of claims 1 to 3 .

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