JP2021012323A - Developing roller, developing device, and image forming apparatus - Google Patents

Abstract

To provide a developing roller that prevents the occurrence of white stripes and is excellent in storage stability, a developing device, and an image forming apparatus.SOLUTION: A developing roller comprises an elastic layer 12, an intermediate layer 13, and a coating layer 15 on an outer peripheral surface of a shaft body 11. The elastic layer 12 is formed of solid silicone rubber having semiconductivity. The intermediate layer 13 is formed of a urethane resin containing restorable particles 14 with a restoration rate of 16% or more and 100% or less. The coating layer 15 is formed of a thermosetting resin.SELECTED DRAWING: Figure 2

Description

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

Various image forming devices using an electrophotographic method are adopted in printers such as laser printers and video printers, copiers, facsimiles, and multifunction devices thereof. An image forming apparatus using an electrophotographic method is equipped with a wide variety of rollers. For example, a charging roller that uniformly charges an image carrier such as a photoconductor, a developing roller that carries and conveys a developer and supplies it to the image carrier, and a developer supply roller that supplies the developing roller while charging the developer. Examples thereof include a cleaning roller that receives foreign matter remaining or adhering to the surface of the image carrier by contacting or pressing against the image carrier, and a fixing roller that fixes a developer image transferred to a recording body such as a recording paper.
Of these, the developing roller supplies the developer to the image carrier by bringing it into contact with the image carrier and rotating it.

When the developing roller is stored for a long time in a state of being in contact with the image carrier, nip marks may be formed on the surface of the developing roller. When a nip mark is generated, the nip mark is not restored at an early stage even if the developing roller is rotated during the next use, so that the developer is not supported on that part and a white horizontal line, a so-called white streak, is formed on the image. appear.

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 apparatus, and an image forming apparatus having excellent storage stability in which the generation of white streaks is suppressed.

In the present invention, an elastic layer, an intermediate layer, and a coating layer are provided on the outer peripheral surface of the shaft body, the elastic layer is made of a solid silicone rubber having semiconductivity, and the intermediate layer has a restoration rate of 16% or more. A developing roller made of a urethane resin containing 100% or less of recoverable particles, and a coating layer made of a thermosetting resin.

The thickness of the intermediate layer is preferably 20 μm or more and 100 μm or less.

It is preferable that the surface of the coating layer has irregularities for supporting the developer.

It is preferable that the thickness of the intermediate layer is larger than the average particle diameter of the restorative particles, the coating layer contains a surface roughness material, and irregularities are formed by the surface roughness material.

Further, the unevenness may be formed by the restorative particles contained in the intermediate layer.

Further, the unevenness may be formed by the surface roughness material contained in the coating layer and the restorative particles contained in the intermediate layer.

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 apparatus and an image forming apparatus having excellent storage stability in which the generation of white streaks is suppressed.

It is a schematic perspective view which shows one Embodiment of the developing roller of this invention. FIG. 1 is a sectional view taken along the line AA of FIG. It is sectional drawing which shows the other embodiment of this invention. It is sectional drawing which shows still another Embodiment of this invention. It is the schematic which shows the measuring method of the restoration rate of the restorative particle. It is a top view which shows the measurement position of the average particle diameter of a restorative particle. It is a load and unloading curve obtained in the measurement of the stability of the restorative particles. It is the schematic sectional drawing which shows one Embodiment of the image forming apparatus of this 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]
As shown in FIGS. 1 and 2, the developing roller 10 of the present invention includes an elastic layer 12, an intermediate layer 13, and a coating layer 15 on the outer peripheral surface of the shaft body 11. The elastic layer 12 is made of a semi-conductive solid silicone rubber, the intermediate layer 13 is made of a urethane resin containing recoverable particles 14 having a recovery rate of 16% or more and 40% or less, and the coating layer 15 is made of a urethane resin. , It is made of thermosetting resin.
Hereinafter, the configuration of the developing roller 10 of the present invention will be described.

(Axis body)
As the shaft body 11, preferably, a shaft body having conductivity and used in a conventionally known developing roller can be used. The shaft body 11 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 11 made of such a metal is also generally known by the name of "core metal".

The shaft body 11 may contain an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft body 11 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 11 can be obtained, for example, by plating a core body made of an insulating resin to make it conductive.
The shaft body 11 is preferably a core metal in order to obtain good conductivity.

The shape of the shaft body 11 is preferably rod-shaped, tubular, or the like. The cross-sectional shape of the shaft body 11 may be, for example, circular or elliptical, or non-circular such as polygonal. The outer peripheral surface of the shaft body 11 may be subjected to treatments such as cleaning treatment, degreasing treatment, and primer treatment in order to improve the adhesiveness with the elastic layer 12.

The length of the shaft body 11 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 11 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 11 (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 11 (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 12 is formed by heating and curing the silicone rubber composition on the outer peripheral surface of the shaft body 11.
The thickness of the elastic layer 12 is preferably 1 mm or more and 10 mm or less, and more preferably 2 mm or more and 6 mm or less.
The rubber composition for forming the elastic layer 12 preferably contains a silicone rubber, a conductivity-imparting agent, and optionally various additives. Examples of the silicone rubber composition include an addition-curing type mirable conductive silicone rubber composition and an addition-curing type liquid conductive silicone rubber composition.

-Additional curing type 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. You can.
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. R ¹ 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 12 or less, and more preferably 1 or more and 8 or less.

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

(A) Organopolysiloxane has a trialkylsilyl group such as a trimethylsilyl group, a dialkylaralkylsilyl group such as a dimethylvinylsilyl group, a dialkylhydroxysilyl group such as a dimethylhydroxysilyl group, a trivinylsilyl group and the like at the end of the molecular chain. It is preferably sealed with a trialal killsilyl group or the like.

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

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

The organopolysiloxane (A) preferably has a kinematic viscosity at 25 ° C. of 100 cSt or more, and more preferably 100,000 cSt or more and 10000000 cSt or less. The degree of polymerization of (A) organopolysiloxane is preferably, for example, 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 diameter using a particle size distribution measuring device by a laser light diffraction method.

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

The addition-curable mirabable conductive silicone rubber composition may further contain additives other than (A) to (C). Additives include, for example, auxiliaries (chain extenders, crosslinkers, 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 such as dimethylsiloxane oil, polyether-modified silicone oil, silanol, diphenylsilanediol and α, ω-dimethylsiloxanediol, 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 _3/4 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.

The filler (F) 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 12 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 12 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, diatomaceous earth, pearlite, and pulverized foamed pearlite can be preferably used as the (F) filler.

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

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

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

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

The elastic layer 12 is formed on the outer peripheral surface of the shaft body 11 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 12 is particularly continuous vulcanization by extrusion molding, pressing, molding by injection, etc. There are no restrictions. When the rubber composition is an addition-curable mirable conductive silicone rubber composition, for example, extrusion molding or the like can be selected, and when the rubber composition is an addition-curable liquid conductive silicone rubber composition. Can select, for example, a molding method using a mold. Further, it may be formed by grinding or polishing an elastic body (cured product of a silicone rubber composition) formed on the shaft body 11.

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 mirable conductive silicone rubber composition. The heating time is preferably several seconds or more and 1 hour or less, and more preferably 10 seconds or more and 35 minutes or less. In the case of the addition-curable liquid conductive silicone rubber composition, the heating temperature is preferably 100 ° C. or higher and 300 ° C. or lower, and more preferably 110 ° C. or higher and 200 ° C. or lower. The heating time is preferably 5 minutes or more and 5 hours or less, and more preferably 1 hour or more and 3 hours or less. Further, if necessary, secondary vulcanization may be performed. In the case of the addition-curing type mirable conductive silicone rubber composition, for example, curing conditions of about 1 hour or more and 20 hours or less at 100 ° C. or higher and 200 ° C. or lower are selected. Further, in the case of the addition-curing type liquid conductive silicone rubber composition, for example, curing conditions of about 2 hours or more and 70 hours or less at 120 ° C. or higher and 250 ° C. or lower are selected. In addition, 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, crosslinkers, 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 low molecular weight siloxane ester, polyether-modified silicone oil, silanol, and phenylsilanediol. Further, heat resistance improvers such as iron octylate, iron oxide and cerium oxide can be mentioned. Further, various carbon functional silanes, various olefin elastomers and the like for improving adhesiveness, molding processability and the like may be used. Further, a halogen compound or the like that imparts flame retardancy may be used.

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

The thickness of the elastic layer 12 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 10.

The outer diameter of the elastic layer 12 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 12 may be UV-treated for the purpose of improving the adhesiveness with the intermediate layer 13 described later.

The method of forming the elastic layer 12 is not particularly limited. For example, the elastic layer 12 may be formed by a method such as extrusion molding or LIMS molding of the silicone rubber composition. Further, the elastic layer 12 may be formed by grinding or polishing an elastic body (cured product of a silicone rubber composition) formed on the shaft body 11.

-Other ingredients-
The silicone rubber composition may further contain various additives other than the above. Examples of various additives include auxiliary agents (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 receiver, thermal conductivity improver, mold release agent, solvent and the like.

(Middle layer)
The intermediate layer 13 is made of a urethane resin containing recoverable particles having a recovery rate of 16% or more and 100% or less. By using such an intermediate layer 13, the restoring force of the intermediate layer 13 can be made higher than that of the elastic layer 12 made of silicone rubber, so that it is possible to prevent the developing roller 10 from being dented during long-term storage. Can be done. Therefore, even if the developing roller 10 is driven after long-term storage, a good image can be obtained without white streaks.
In the present specification, the elastic modulus of each layer indicates the indentation elastic modulus. The indentation elastic modulus can be measured by the measuring method described in Examples described later.
The indentation elastic modulus of the intermediate layer 13 is preferably 0.1 MPa or more and 40 MPa or less, and more preferably 1 MPa or more and 20 MPa or less.

− Thickness −
The thickness T ₁₃ (see FIG. 2) of the intermediate layer 13 is preferably 20 μm or more and 100 μm or less, and more preferably 30 μm or more and 100 μm or less. When the thickness T ₁₃ of the intermediate layer 13 falls within the above range, it is possible to reduce indentation amount of the elastic layer of the developing roller 10. In addition, the restoring force of the thickness makes it easy for the dent to return to its original shape.

-Surface roughness Ra-
The surface roughness Ra of the intermediate layer 13 is preferably 1.2 or less, and more preferably 1.0 or less.
The surface roughness Ra is a value measured by the measuring method shown in Examples described later.

-Stable particles-
The restorative particles 14 contained in the intermediate layer 13 have a restorative rate of 16% or more and 100% or less. By having a restoration rate of 16% or more, the intermediate layer 13 having high restoration property can be obtained. The restoration rate is preferably 25% or more and 100% or less, and more preferably 30% or more and 100 or less.
The restorative particles 14 preferably have an average particle diameter of 1 μm or more and 100 μm or less, and more preferably 2 μm or more and 50 μm or less. When the average particle size is within this range, the resilience of the intermediate layer 13 can be further enhanced.

As the recoverable particles 14 in the present invention, urethane resin particles and acrylic resin particles are preferable. Examples of commercially available acrylic resin particles include "XX-4132Z" (trade name, φ10 μm) and “AFX-8” (trade name, φ8 μm) manufactured by Sekisui Plastics Co., Ltd.

-Measurement method of restoration rate-
The restoration rate of the recoverable particles 14 can be measured by, for example, the following method.
Dynamic micro hardness tester: DUH-211S (trade name), manufactured by Shimadzu Sample: Urethane resin particles Upper pressurizing indenter: 20 μm
Measurement mode: Load and unload test Maximum test force: 9.810 "mN"
Minimum test force: 0.49 "mN"
Load speed: 0.7437 "mN / sec"
Load holding time: 3 "sec"

As shown in FIGS. 5 and 6, after a very small amount of the restorative particles 14 are sprayed on the sample table 22, the diameters (d _X , d _Y ) in the _X and Y directions are measured, and the average thereof is taken as the particle diameter (d). To do. Next, the indenter 21 presses the restorative particles one by one to perform a loading and unloading test (see FIG. 7).
Next, the obtained average is calculated from the particle size (d), L1 and L2, and the compression rate and restoration rate of the sample are calculated by the following equations.
Compression rate Cr = L1 / d x 100 (%)
Restoration rate Rr = L2 / d × 100 (%)

-Resin composition for intermediate layer-
The intermediate layer 13 is made of urethane resin. The urethane resin is preferably polyester urethane or acrylic urethane.
The intermediate layer 13 can be formed from the resin composition for an intermediate layer containing the restorative particles 14, (a) polyol, (b) isocyanate, and (c) ionic conductive material.
Hereinafter, each component (a) to (c) of the resin composition for the intermediate layer will be described.

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

The polyether polyols include, for example, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polypropylene glycol-ethylene glycol, polytetramethylene ether glycols, copolymer polyols of tetrahydrofuran and alkylene oxide, various modified products thereof, or their modified products. 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 monomers and unsaturated polymers.

Polycarbonate polyols have two or more carbonate bonds and two or more hydroxyl groups in the molecule. Examples of the polycarbonate polyol include a condensation reaction product of the polyol and the carbonate compound. Further, examples of the carbonate compound include dialkyl carbonate, diaryl carbonate, alkylene carbonate and the like. 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, more preferably 1000 to 5000, and the ionic liquid is a hydroxyl group-containing ionic liquid in that it has excellent compatibility with isocyanates and the like, which will be described later. In the case of, it is preferable to have a number average molecular weight of 800 to 15,000, and more preferably to have a number average molecular weight of 1000 to 5000. The number average molecular weight is the molecular weight when converted to standard polystyrene by gel permeation chromatography (GPC).

(B) Isocyanates The isocyanates may be various isocyanates usually used for the preparation of 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 diisocyanate), xylene diisocyanate, naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI), Examples thereof include trizine diisocyanate (TODI) and metaphenylene diisocyanate.
Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), orthotoluidine diisocyanate, lysine diisocyanate methyl ester, isophorone diisocyanate (IPDI), norbornan diisocyanate methyl, and transcyclohexane. Examples thereof include -1,4-diisocyanate and triphenylmethane-4,4', 4''-triisocyanate.
Derivatives include polyisocyanate polynuclears, urethane modified products (including urethane prepolymers) modified with polyols, dimer by uretidine formation, isocyanurate modified products, carbodiimide modified products, uretonimine modified products, alohanate modified products, etc. Examples include urethane 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, and more preferably 700 to 1500.

The (b) isocyanate used in the resin composition for the intermediate layer is preferably a polyisocyanate. (B) The number of isocyanate groups in one molecule of isocyanate is preferably more than 2, more preferably 2.5 or more, still more preferably 3 or more.
The mixing ratio of the mixture of the polyol and the polyisocyanate is not particularly limited, but usually, the molar ratio (NCO / OH) of the hydroxyl group (OH) contained in the polyol and the isocyanate group (NCO) contained in the polyisocyanate is 0. It is preferably 7. or more and 1.15 or less. This molar ratio (NCO / OH) is more preferably 0.85 or more and 1.10 or less in that hydrolysis of polyurethane can be prevented. Actually, in consideration of the work environment and work error, an amount equivalent to 3 to 4 times the appropriate molar ratio may be blended.

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

(C) Ion conductive material Examples of the ion conductive material include sodium perchlorate, lithium perchlorate, calcium perchlorate, lithium chloride, lithium bis (trifluoromethanesulfonyl) imide, potassium bis (trifluoromethanesulfonyl) imide and the like. Inorganic ionic conductive substances and the like. The content of the ionic conductive material in the resin composition for the intermediate layer is preferably 0.01 part by mass or more and 5 parts by mass or less, and 0.1 part by mass or more, with respect to 100 parts by mass of the resin composition for the intermediate layer. It is more preferably 3 parts by mass or less.

--Other ingredients ---
The intermediate layer 13 may contain the surface roughness material 16. The surface roughness material 16 is a particle that adjusts the surface roughness of the intermediate layer 13. The average particle size of the surface roughness material 16 blended in the intermediate layer 13 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 16 in the intermediate layer 13, the surface roughness can be easily adjusted to an appropriate range. The average particle size of the surface roughness material 16 can be measured as a median diameter by using a particle size distribution measuring device by a laser light diffraction method.

The type of the surface roughness material 16 blended in the coating layer 15 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 16 in the resin composition for the intermediate layer 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 composition for the intermediate layer, and is preferably 1 part by mass or more. It is more preferably 40 parts by mass or less.

The intermediate layer 13 may further contain additives other than the above. For example, the intermediate layer 13 may further contain additives such as a silane coupling agent, a lubricant, a polymerization catalyst, a dispersant, and a filler.

The intermediate layer 13 is cured by applying a resin composition for an intermediate layer on the elastic layer 12 and polymerizing (a) a polyol component and (b) an 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 isocyanate component, and may be, for example, ethyl acetate, butyl acetate or the like.

The coating of the resin composition for the intermediate layer is, for example, a coating method in which the coating liquid of the resin composition for the intermediate layer is applied, a dipping method in which an elastic layer or the like is immersed in the coating liquid, an elastic layer or the like in 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 resin composition for the intermediate layer may be applied as it is, or the resin composition for the intermediate layer 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 resin composition for the intermediate layer coated in this manner may be any method as long as the heat required for curing the resin composition for the intermediate layer is applied. For example, the resin composition for the intermediate layer 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 in a high humidity, and the like. The heating temperature when the resin composition for the intermediate 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 intermediate layer 13 formed in this way, the precursor forming the resin and the ionic conductive material may react and become one body, or a composite may be formed. Further, the ionic conductive material may not react with the precursor forming the resin and may be dispersed in the resin.

(Coating layer)
The coating layer 15 is made of a thermosetting resin. Further, the coating layer 15 is the outer periphery of the intermediate layer 13 and is provided on the outermost surface of the developing roller 10 and has a role of supporting the developing agent.
The coating layer 15 is formed by applying a coating layer resin composition to the outer peripheral surface of the intermediate layer 13 and then heating and curing the coated resin composition for the coating layer. As the resin composition for the coating layer, the same material as the resin composition for the intermediate layer can be used.
Since the coating layer 15 does not contain the restoring particles 14, the restoring force of the coating layer 15 is smaller than that of the intermediate layer 13.

As shown in FIG. 2, the coating layer 15 has irregularities for supporting the developer. The unevenness of the coating layer 15 can be formed by including the surface roughness material 16 in the coating layer 15. Examples of the surface roughness material 16 include a surface roughness material that can be used in the intermediate layer 13.
When the thickness T ₁₃ of the intermediate layer 13 is larger than the average particle diameter of the restorative particles 14, that is, when the surface of the intermediate layer 13 is smooth, the coating layer 15 includes the surface roughness material 16 and the surface roughness material 16 is included. It is preferable that unevenness is formed by.
In that case, the surface roughness Ra of the intermediate layer 13 is preferably 0.5 or less and smaller than the surface roughness of the elastic layer 12.

Further, as shown in FIG. 3, by adjusting the average particle diameter and / or the content of the restorative particles 14 in the resin composition for the intermediate layer for producing the intermediate layer 13, the surface of the intermediate layer 13 is formed. By forming the coating layer 15 that does not include the surface roughness material 16 on the uneven surface after forming the unevenness, the unevenness reflecting the unevenness of the intermediate layer 13 can be formed on the surface 15a of the coating layer 15.

Further, as shown in FIG. 4, after forming irregularities on the surface of the intermediate layer 13, an unevenness is formed on the surface 15a of the coating layer 15 by forming a coating layer 15 containing the surface roughness material 16 on the irregularities. Can also be formed.

-Surface roughness Ra-
The coating layer 15 produced as described above preferably has a surface roughness Ra of 0.4 or more and 1.5 or less. The surface roughness Ra is more preferably 0.4 or more and 0.9 or less. When the surface roughness Ra is in the above range, the developer transportability is improved and more excellent printing characteristics can be obtained.

(Other configurations)
The developing roller 10 of the present invention includes an adhesive layer, a primer layer, or the like between the shaft body 11 and the elastic layer 12, and between the elastic layer 12, the intermediate layer 13, the intermediate layer 13, and the coating layer 15. May be good. Here, among these layers, in particular, the adhesive layer and the primer layer provided between the intermediate layer 13 and the coating layer 15 are adjusted in their electrical characteristics to improve the electrical characteristics of the developing roller 10. It can be adjusted, whereby the developing performance of the developing roller 10 can be satisfactorily adjusted.

As the primer layer, those usually used as the primer layer of the developing roller can be used. For example, by forming the primer layer made of urethane resin having an ester group, the developing performance of the developing roller 10 can be improved. Can be maintained.

[Developer and image forming device]
Next, an embodiment of the developing apparatus and the image forming apparatus of the present invention will be described with reference to FIG.
The developing roller 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 in the image forming apparatus is not particularly limited.

The image forming apparatus 100 connects a plurality of image carriers 111B, 111C, 111M and 111Y mounted on the developing units B, C, M and Y of each color (black, cyan, magenta, yellow) in series on the transfer transfer belt 146. It is a tandem type color image forming apparatus arranged in, and development units B, C, M and Y are arranged in series on a transfer transfer belt 146. The developing unit B carries an image via an image carrier 111B, for example, a photoconductor (also referred to as a photosensitive drum), a charging means 112B, for example, a charging roller, an exposure means 113B, a developing device 120B, and a transfer transfer belt 146. A transfer means 114B that comes into contact with the body 111B, for example, a transfer roller and a cleaning means 115B are provided.

The developing device 120B is an example of the developing device of the present invention, and includes a developer carrier 123B and a developing agent 122B as shown in FIG. That is, the developing rollers of the present invention are mounted as the developing agent carriers 123B, 123C, 123M and 123Y. Specifically, the developing apparatus 120B includes a housing 121B accommodating a one-component non-magnetic developer 122B, a developing agent carrier 123B for supplying the developing agent 122B to the image carrier 111B, and a developing agent carrier 123B. A toner supply roller 125B for supplying the developer 122B and a developer amount adjusting means 124B for adjusting the thickness of the developer 122B, for example, a blade, are provided. In the developing apparatus 120B, the developer amount adjusting means 124B is in contact with or pressure-contacted with the outer peripheral surface of the developer carrier 123B as shown in FIG. That is, the developing device 120B is a "contact developing device". The developing units C, M and Y are basically configured in the same manner as the developing unit B, and the same elements are designated by the same reference numerals and symbols C, M or Y indicating each unit, and the description thereof will be omitted. ..

In the image forming apparatus 100, the developer carrier 123B of the developing apparatus 120B is arranged so that its surface is in contact with or pressed against the surface of the image carrier 111B. Similar to the developing device 120B, the developing devices 120C, 120M and 120Y are also arranged so that the surfaces of the developing agent carriers 123C, 123M and 123Y come into contact with or press contact with the surfaces of the image carriers 111C, 111M and 111Y. That is, the image forming apparatus 100 is a "contact type image forming apparatus".

The fixing means 130 is arranged on the downstream side of the developing unit Y. The fixing means 130 includes a fixing roller 131, an endless belt support roller 133 arranged in the vicinity of the fixing roller 131, a fixing roller 131, and an endless belt in a housing 134 having an opening 135 through which the recording body 116 is passed. An endless belt 136 wound around the support roller 133 and a pressure roller 132 arranged to face the fixing roller 131 are provided, and the fixing roller 131 and the pressure roller 132 are brought into contact with each other or pressure-welded to each other via the endless belt 136. It is a pressure heat fixing device that is rotatably supported so as to perform. At the bottom of the image forming apparatus 100, a cassette 141 accommodating the recording body 116 is installed. The transfer transfer belt 146 is wound around a plurality of support rollers 142.

The developing agents 122B, 122C, 122M and 122Y used in the image forming apparatus 100 may be either a dry developing agent or a wet developing agent as long as they can be charged by friction, and may be a non-magnetic developing agent or magnetic developing. It may be an agent. In the housings 121B, 121C, 121M and 121Y of the developing units B, C, M and Y, one component non-magnetic black developer 122B, cyan developer 122C, magenta developer 122M and yellow developer 122Y are contained. Each is stored.

The image forming apparatus 100 forms a color image on the recording body 116 as follows. First, in the developing unit B, an electrostatic latent image is formed on the surface of the image carrier 111B charged by the charging means 112B by the exposure means 113B, and a black electrostatic latent image is formed by the developer 122B supplied by the developing agent carrier 123B. The image is developed. Then, when the recording body 116 passes between the transfer means 114B and the image carrier 111B, the black electrostatic latent image is transferred to the surface of the recording body 116. Next, in the same manner as the development unit B, the cyan image, the magenta image, and the yellow image are superimposed on the recording body 116 in which the electrostatic latent image is visualized as a black image by the development units C, M, and Y, respectively. The color image is visualized. Next, in the recording body 116 in which the color image is visualized, the color image is fixed to the recording body 116 as a permanent image by the fixing means 130. In this way, a color image can be formed on the recording body 116.

The developing apparatus 120B includes the developing roller (developer carrier 123B) of the present invention, which is excellent in developer transportability and suppresses the occurrence of toner filming to form a high-density, high-quality image for a long period of time. Can contribute to. Further, the image forming apparatus 100 provided with the developing apparatus 120B 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 is an electrophotographic image forming apparatus, but in the present invention, the image forming apparatus is not limited to the electrophotographic system, and may be, for example, an electrostatic type image forming apparatus. .. Further, the image forming apparatus in which the developing rollers of the present invention are arranged is not limited to a tandem type color image forming apparatus in which a plurality of image carriers equipped with developing units of each color are arranged in series on a transfer transfer belt, for example. , A monochrome image forming apparatus provided with a single developing unit, a 4-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier onto an endless belt, or the like. Further, the developer used in the image forming apparatus is a one-component non-magnetic developer, but in the present invention, it may be a one-component magnetic developer or a two-component non-magnetic developer. Alternatively, it may be a two-component magnetic developer.

The image forming apparatus is a contact type image forming apparatus which is arranged in contact with or in contact with 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 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 scope of claims that the invention to which such a modification or improvement is added 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]
(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 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.

(Elastic layer)
An elastic layer was formed on the shaft body by the following method. That is, 50 parts by mass of a mixture of vinyl group-containing silicone raw rubber and a silica-based filler (silicone rubber composition "KE-9410U" manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and a mixture of vinyl group-containing silicone raw rubber and carbon black ( A silicone rubber composition manufactured by Shin-Etsu Chemical Industry Co., Ltd. was mixed with 50 parts by mass of a silicone rubber composition "KE-3502U") to prepare a silicone rubber composition. Next, 100 parts by mass of this silicone rubber composition, 2.0 parts by mass of the addition reaction cross-linking agent "C-153A" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), and a platinum catalyst (trade name "CAT-PL2"). 0.2 parts by mass and 0.5 parts by mass of the reaction controller "R-153A" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) are sufficiently kneaded with a pressure kneader to sufficiently knead the addition-curable mirable conductive silicone. A rubber composition was prepared.

An elastic body made of a rubber material was formed on the outer peripheral surface of the shaft by extrusion molding using the prepared addition-curable mirable conductive silicone rubber composition. In extrusion molding, the addition-curable mirable conductive silicone rubber composition is heated at 360 ° C. for 5 minutes using an infrared heating furnace (IR furnace), and further heated at 200 ° C. for 4 hours using a gear oven. It was cured. This elastic body was polished to form an elastic layer having an outer diameter of 16 mm.
The surface roughness of the elastic layer was measured by Surfcom 1400G manufactured by Tokyo Seimitsu Co., Ltd. to obtain Ra = 1.2. The indentation elastic modulus of this rubber was 2.5 MPa.

(Middle layer)
Next, a resin composition for forming the intermediate layer was prepared as follows. That is, 28 parts by mass of polyester polyol, 18 parts by mass of hexamethylene diisocyanate (trade name "Duranate E402-80B", manufactured by Asahi Kasei), 0.03 parts by mass of dibutyltin dilaurate (manufactured by Showa Kagaku), carbon black (trade name "Talker Black #"). 4500 ”, 0.5 parts by mass of Tokai Carbon Co., Ltd.) and 0.1 parts by mass of ionic conductive material (trade name“ EF-N112 ”, manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) are mixed to form a polyester urethane resin. 25 parts by mass of recoverable particles (trade name "XX-4132Z" Sekisui Kasei Kogyo Co., Ltd.) with an average particle diameter of φ10 μm and a restoration rate of 33% with respect to 100 parts by mass of this resin composition, and 30 parts by mass of thinner The parts were mixed to obtain a resin composition for an intermediate layer.

After excimer treatment is applied to the surface of the elastic layer, the prepared resin composition for the intermediate layer is applied to the outer peripheral surface of the elastic layer by a roll coating method, and heated at 160 ° C. for 10 minutes to obtain an intermediate layer having a thickness of about 20 μm. Was formed.
When the surface of this intermediate layer was measured with a surface roughness meter Surfcom 1400G manufactured by Tokyo Seimitsu, Ra = 0.3. The indentation elastic modulus of this elastic layer was 2.36 MPa.

(Coating layer)
Next, a resin composition for a coating layer for forming a coating layer was prepared as follows.
That is, 20 parts by mass of acrylic polyol, 18 parts by mass of hexamethylene diisocyanate (trade name "Duranate E402-80", manufactured by Asahi Kasei), 0.03 parts by mass of dibutyltin dilaurate (manufactured by Showa Kagaku), ionic conductive agent (trade name "EF-"). N112 ”, manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) 0.1 parts by mass and 0.1 parts by mass of a fluorine-based surface preparation agent were mixed to prepare an acrylic urethane resin composition. 6 parts by mass of silica (average particle diameter 6.4 μm, trade name “ACEMATT OK-212”, manufactured by Evonik Degussa) and 30 parts by mass of thinner are mixed with 100 parts by mass of the acrylic urethane resin composition to form a coating layer. A resin composition for use was obtained.

The prepared resin composition for a coating layer was applied onto the obtained intermediate layer by a spray coating method and heated at 160 ° C. for 30 minutes to form a coating layer having a thickness of about 5 μm to obtain a developing roller.
The surface roughness of the developing roller was Ra = 1.0. The indentation elastic modulus of the coating layer was 1.76 MPa.

[Example 2]
An elastic layer was formed in the same manner as in Example 1, and the resin composition of the intermediate layer was 20 parts by mass of acrylic polyol, 18 parts by mass of hexamethylene diisocyanate (trade name "Duranate E402-80", manufactured by Asahi Kasei Co., Ltd.), and dibutyltin. An acrylic urethane resin composition was prepared by mixing 0.03 parts by mass of dilaurate (manufactured by Showa Kagaku) and 0.1 parts by mass of an ionic conductive agent (trade name "EF-N112", manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.). , The restoring particles were changed to 45 parts by mass with respect to 100 parts by mass of the acrylic urethane resin composition, coated on the elastic layer treated with excimation in the same manner as in Example 1 by the spray coating method, and heated at 160 ° C. for 10 minutes. An intermediate layer having a thickness of 20 μm was formed.
The intermediate layer had many particles and had irregularities, and when the surface roughness was measured, Ra = 0.8.
Next, a coating layer resin composition obtained by removing silica from the coating layer resin composition of Example 1 was provided with a dry thickness of 1 to 2 μm to obtain a developing roller having a surface roughness Ra = 0.8.

[Example 3]
The restorative particles of Example 1 were 35 parts by mass, and the elastic layer and the intermediate layer were formed by the same method as in Example 1. The surface roughness of the intermediate layer was Ra = 0.5.
Next, the silica of the resin composition for the coating layer of Example 1 was changed to 3 parts by mass of recoverable particles φ10 μm (trade name “XX-4132Z”, manufactured by Sekisui Plastics Co., Ltd.), and the resin composition for the coating layer was changed. A coating film was formed on the intermediate layer so that the thickness after curing was about 6 μm.
The surface roughness of the developing roller was Ra = 1.1.

[Example 4]
The same as in Example 1 except that the recoverable particles in the intermediate layer were changed to particles having a recovery rate of 20% and a diameter of 8 μm (trade name: “AFX-8”, manufactured by Sekisui Plastics Co., Ltd.) and the thickness was 100 μm. A developing roller was produced.
The surface roughness of the intermediate layer was Ra = 0.5. The surface roughness of the developing roller was Ra = 1.0.

[Example 5]
A developing roller was produced in the same manner as in Example 4 except that the thickness of the intermediate layer was 20 μm. The surface roughness of the intermediate layer was Ra = 0.6. The surface roughness of the coating layer was Ra = 1.1.

[Comparative Example 1]
A developing roller was produced in the same manner as in Example 1 except that the intermediate layer did not contain the restorative particles. After the storage test, it was left for 24 hours, and in the printing test, dented streaks were generated and did not disappear even after printing 20 sheets.

[Comparative Example 2]
A developing roller was produced in the same manner as in Example 1 except that the trade name was changed to "C-400, φ15 μm" (urethane resin particles manufactured by Negami Kogyo Co., Ltd.) instead of the recoverable particles. The urethane resin particles had a restoration rate of 15%. When printing, horizontal streaks occurred, and even after printing 20 sheets, it did not heal. That is, the dent could not be improved.

[Evaluation]
For the developing rollers of Examples and Comparative Examples, the surface roughness of the elastic layer, the intermediate layer and the coating layer, and the indentation elastic modulus were measured.
Further, an image forming apparatus C610dn2 (model number, manufactured by Oki Data Corporation) was prepared, and the developing rollers of the image forming apparatus were replaced with the developing rollers of the respective Examples and Comparative Examples to obtain an image forming apparatus. The storage stability (printing state) of the obtained image forming apparatus was observed by the following method.
The evaluation results are shown in Table 1. In Table 1, the units of numerical values for the elastic layer, the intermediate layer, and the coating layer are parts by mass.

(Measurement method of arithmetic mean roughness Ra)
The arithmetic average roughness Ra of the developing roller produced as described above was measured by a surface roughness meter (trade name "Surfcom 1400G", manufactured by Tokyo Seimitsu Co., Ltd.) based on JIS B0601-2001.

(Measurement of indentation elastic modulus)
Measured by the method described in ISO 14577-1. As the measuring device, "Heiditron TI PREMIER" (trade name) manufactured by Bruker Japan Co., Ltd. was used.

(Preservation)
The developing rollers prepared in Examples and Comparative Examples were incorporated into a cartridge, stored at 50 ° C. and 60% RH for 1 month, left at room temperature for 3 hours, and incorporated into a printer for printing.
A: Horizontal streaks do not occur in the initial printing B: Horizontal streaks disappear by 20 sheets of printing C: Horizontal streaks occur from the initial printing, and horizontal streaks can be seen even after printing 20 sheets

10 Develop roller 11 Axis 12 Elastic layer 13 Intermediate layer 14 Restoring particles 15 Coating layer 16 grains Surface roughness material 100 Image forming apparatus 111B, 111C, 111M, 111Y Image carrier 112B, 112C, 112M, 112Y Charging means 113B, 113C, 113M, 113Y Exposure means 114B, 114C, 114M, 114Y Transfer means 115B, 115C, 115M, 115Y Cleaning means 116 Recorder 120B, 120C, 120M, 120Y Developer 121B, 121C, 121M, 121Y, 134 Housing 122B, 122C, 122M, 122Y Developer 123B, 123C, 123M, 123Y Developer Carrier 124B, 124C, 124M, 124Y Developer Amount Adjusting Means 125B, 125C, 125M, 125Y Toner Supply Roller 130 Fixing Means 131 Fixing Roller 132 Pressurizing Roller 133 Endless Belt Support Roller 135 Opening 136 Endless Belt 141 Cassette 142 Support Roller 146 Transfer Transfer Belt B, C, M, Y Development Unit

Claims (8)

An elastic layer, an intermediate layer, and a coating layer are provided on the outer peripheral surface of the shaft body.
The elastic layer is made of a semi-conductive solid silicone rubber.
The intermediate layer is made of a urethane resin containing recoverable particles having a recovery rate of 16% or more and 100% or less.
A developing roller in which the coating layer is made of a thermosetting resin. The developing roller according to claim 1, wherein the thickness of the intermediate layer is 20 μm or more and 100 μm or less. The developing roller according to claim 1 or 2, which has irregularities on the surface of the coating layer for supporting the developing agent. The thickness of the intermediate layer is larger than the average particle size of the restorative particles,
The developing roller according to claim 3, wherein the coating layer contains a surface roughness material, and the unevenness is formed by the surface roughness material. The developing roller according to claim 3, wherein the unevenness is formed by the restorative particles contained in the intermediate layer. The developing roller according to claim 3, wherein the unevenness is formed by the surface roughness material contained in the coating layer and the restorative particles contained in the intermediate layer. A developing apparatus including the developing roller according to any one of claims 1 to 6. An image forming apparatus including the developing roller according to any one of claims 1 to 6.

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