CN112955824A

CN112955824A - Developing roller, developing device, and image forming apparatus

Info

Publication number: CN112955824A
Application number: CN201980071075.XA
Authority: CN
Inventors: 加藤慧; 广谷泰男; 高梨寛之
Original assignee: Shin Etsu Polymer Co Ltd
Current assignee: Shin Etsu Polymer Co Ltd
Priority date: 2018-11-27
Filing date: 2019-11-11
Publication date: 2021-06-11
Anticipated expiration: 2039-11-11
Also published as: JP7207632B2; WO2020110686A1; CN112955824B; JP2020086171A

Abstract

A developing roller 1 comprises an elastic layer 3 formed on the outer peripheral surface of a shaft body 2, and a coating layer 4 formed on the outer peripheral surface of the elastic layer 3; wherein the coating layer 4 is formed by thermally curing a coating layer resin composition containing (a) a polyol, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material; wherein the polyol (a) contains at least one of a polyol (a1) having a non-reactive silicone group in a side chain and a silicone oil (a2) having a single-ended glycol group.

Description

Developing roller, developing device, and image forming apparatus

Technical Field

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

Background

A developing roller used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine employing an electrophotographic system has a capability of conveying a developer onto an image carrier on which an electrostatic latent image is formed. The developer conveying performance of the developing roller affects the quality of the image forming apparatus, particularly the print density. Therefore, it has been studied to improve the developer conveying performance of the developing roller by forming irregularities on the surface of the developing roller and adjusting the electrical characteristics of various materials constituting the developing roller.

The developing roller is rotated in the same direction and generates a speed difference in a state of being in contact with the photosensitive drum, thereby causing toner to adhere to the photosensitive drum. Therefore, if the smoothness of the developing roller surface is poor, it will be repeatedly caught and released by the photosensitive drum. In this case, since the toner cannot be uniformly supplied to the photosensitive drum, a band-like shadow, a so-called banding, occurs in the image.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above problems, and an object thereof is to provide a developing roller, a developing device, and an image forming apparatus in which banding can be suppressed well.

Means for solving the problems

The present inventors have conducted intensive studies on a resin used in a coating layer in order to prevent a developing roller from being caught by a photosensitive drum, and have found that a tape can be improved by including a specific polyol in a conditioning component of a urethane resin of the coating layer, thereby completing the present invention.

That is, one embodiment of the present invention is a developing roller including: an elastic layer formed on an outer peripheral surface of the shaft body; and a coating layer formed on an outer peripheral surface of the elastic layer; wherein the coating layer is formed by thermally curing a coating layer resin composition containing (a) a polyol, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material; (a) the polyol contains at least one of (a1) a polyol having a non-reactive silicone group in a side chain and (a2) a single-ended glycol silicone oil.

(a) The content of at least one of the polyol (a1) having a non-reactive silicone group in the side chain and the single-ended glycol silicone oil (a2) in the polyol is preferably 2 mass% or more and 60 mass% or less.

Of the polyol having a non-reactive silicone group in the side chain (a1) and the one-terminal diol-type silicone oil (a2), the polyol having a non-reactive silicone group in the side chain (a1) alone is contained, and the polyol having a non-reactive silicone group in the side chain (a1) is preferably a silicone graft acrylic polyol.

In the above case, the content of the silicone-grafted acrylic polyol in the polyol (a) is preferably 2 mass% or more and 40 mass% or less.

Another embodiment of the present invention is a developing device including the developing roller according to the above embodiment.

Another embodiment of the present invention is an image forming apparatus including the developing roller according to the above embodiment.

Effects of the invention

According to the present invention, it is possible to provide a developing roller, a developing device, and an image forming apparatus in which banding can be suppressed well.

Drawings

Fig. 1 is a schematic perspective view showing one embodiment of a developing roller of the present invention.

Fig. 2 is a schematic cross-sectional view showing an embodiment of an image forming apparatus according to the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail, but the following embodiments are provided for illustrative purposes, and the present invention is not limited to the embodiments shown below.

[ developing roller ]

As shown in fig. 1, a developing roller 1 of the present invention includes a shaft body 2, and an elastic layer 3 provided on an outer peripheral surface of the shaft body 2; and a coating layer 4 provided on the outer peripheral surface of the elastic layer 3.

The structure of the developing roller 1 of the present invention will be described below.

(shaft body)

The shaft body 2 is preferably a shaft body used for a conventional existing developing roller having a conductive property. Preferably, the shaft body 2 is made of at least one metal selected from the group consisting of iron, aluminum, stainless steel, and brass, for example. Such a shaft body 2 made of metal is also generally called "core metal".

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

The shaft body 2 is preferably a core metal to obtain good conductive characteristics.

The shaft body 2 is preferably rod-shaped or tubular. The cross-sectional shape of the shaft body 2 may be circular or elliptical, or may be non-circular, such as polygonal. The outer peripheral surface of the shaft body 2 may be subjected to a cleaning treatment, a degreasing treatment, a primer treatment, or the like to improve adhesion with the elastic layer 3.

The axial length of the shaft body 2 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 print target is a4 size, the axial length of the shaft body 2 is preferably 250mm or more and 320mm or less, and more preferably 260mm or more and 310mm or less. The diameter of the shaft body 2 (the diameter of the circumscribed circle) is not particularly limited, and may be adjusted as appropriate according to the form of the image forming apparatus to be installed. For example, the outer diameter (diameter of circumscribed circle) of the shaft body 2 is preferably 4mm or more and 14mm or less, and more preferably 6mm or more and 10mm or less.

(elastic layer)

The elastic layer 3 is formed by heating and curing a rubber composition on the outer circumferential surface of the shaft body 2. The rubber composition for forming the elastic layer 3 preferably contains rubber, a conductive material, and various additives as needed.

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, isoprene rubber, natural rubber, acrylate rubber, chloroprene rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, fluororubber, and the like. Silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber is particularly preferable because it can reduce compression set, has excellent flexibility in a low-temperature environment, and further has excellent heat resistance, charging characteristics, and the like. Examples of the silicone rubber include crosslinked products of organopolysiloxanes such as dimethylpolysiloxanes and diphenylpolysiloxanes.

Examples of the silicone rubber composition include an addition curing type kneaded conductive silicone rubber composition, an addition curing type liquid conductive silicone rubber composition, and the like.

Addition curing type kneading conductive silicone rubber composition

The addition curing type kneaded conductive silicone rubber composition may be, for example, a composition containing (a) an organopolysiloxane, (B) a filler, and (C) a conductive material, wherein the (a) organopolysiloxane is represented by the following average composition formula (1).

R¹ _nSiO_(4-n)/2...(1)

In the formula (1), n represents a positive number of 1.95 to 2.05. In addition, R¹Represents 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 to 12, more preferably 1 to 8.

As R¹Examples thereof include: alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and dodecyl groups, cycloalkyl groups such as cyclohexyl groups, alkenyl groups such as vinyl, allyl, butenyl and hexenyl groups, aryl groups such as phenyl and tolyl groups, aralkyl groups such as β -phenylpropyl groups, and the like. In addition, R¹These hydrocarbon groups may have hydrogen atoms, some or all of which may be 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 are chloromethyl, trifluoropropyl, cyanoethyl and the like.

(A) The organopolysiloxane is preferably blocked at the molecular chain end by 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 triaralkylsilyl group such as a trivinylsilyl group.

(A) The organopolysiloxane preferably has two or more alkenyl groups in the molecule. (A) The organopolysiloxane is preferably R¹Has an alkenyl group at 0.001 mol% or more and 5 mol% or less (more preferably 0.01 mol% or more and 0.5 mol% or less). Vinyl groups are particularly preferred as the alkenyl groups of the organopolysiloxane (A).

(A) The organopolysiloxane can be obtained, for example, by cohydrolytic condensation of one or two or more organohalosilanes, or by ring-opening polymerization of a cyclic polysiloxane such as a trimer or tetramer of siloxane. (A) The organopolysiloxane may be a substantially linear diorganopolysiloxane or may be partially branched. (A) The organopolysiloxane may also be a mixture of two or more species differing in molecular structure.

(A) The kinematic viscosity of the organopolysiloxane at 25 ℃ is preferably 100cSt or more, more preferably 100000cSt or more and 10000000cSt or less. The polymerization degree of the organopolysiloxane (a) is preferably, for example, 100 or more, and more preferably 3000 or more and 10000 or less.

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

As the silica-based filler, the general formula R is preferably used²Si(OR³)₃The surface-treated silica filler is a surface-treated silica filler obtained by surface-treating the silane coupling agent. Here, R²There may be mentioned a group having a vinyl group or an amino group, such as a glycidyl group, a vinyl group, an aminopropyl group, a methacryloyloxy group, an N-phenylaminopropyl group, a mercapto group and the like. R³May be an alkyl group such as methyl, ethyl, etc. The silane coupling agent is easily available in the form of, for example, trade names "KBM 1003" and "KBE 402" manufactured by shin-Etsu chemical Co. 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 can be used, and for example, a product name "Zeothix 95" manufactured by j.m. huber co.

The amount of the silica-based filler blended 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 the organopolysiloxane (a). The average particle diameter 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 diameter of the silica-based filler can be measured as a median particle diameter by using a particle size distribution measuring apparatus based on a laser diffraction method.

The blending amount of the (C) conductive material 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 the (a) organopolysiloxane. The amount of the conductive material (C) is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the organopolysiloxane (a).

The addition curing type kneaded conductive silicone rubber composition may further contain additives other than (a) to (C). Examples of such additives include: an auxiliary (chain extender, crosslinking agent, etc.), a catalyst, a dispersant, a foaming agent, an antiaging agent, an antioxidant, a pigment, a colorant, a processing aid, a softening agent, a plasticizer, an emulsifier, a heat resistance improver, a flame retardancy improver, an acid acceptor, a thermal conductivity improver, a mold release agent, a solvent, etc.

Specific examples of the additives include: low molecular weight siloxane having both terminal silanol groups blocked, such as dimethylsiloxane oil having a lower degree of polymerization than the organopolysiloxane (A), polyether-modified silicone oil, silanol, diphenylsilanediol, and α, ω -dimethylsilanediol, and a dispersing agent such as silane. Specific examples of the additives include: heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. In addition, various carbon-functional silanes, various olefinic elastomers, and the like can be used as additives to improve adhesion, moldability, and the like.

Addition curing type liquid conductive silicone rubber composition

The addition curing type liquid conductive silicone rubber composition may also contain the following components: for example, (D) an organopolysiloxane containing two or more alkenyl groups in one molecule, (E) an organohydrogenpolysiloxane containing two or more hydrogen atoms bonded to silicon atoms in one molecule, (F) a filler, (G) a conductive material, and (H) an addition reaction catalyst.

The organopolysiloxane (D) is preferably a compound represented by the following average composition formula (2).

R⁴ _aSiO_(4-a)/2...(2)

In 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. In addition, R⁴Represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. However, R of one molecule⁴At least two of which are alkenyl groups. The number of carbon atoms of the hydrocarbon group is preferably 1 to 12, more preferably 1 to 8.

As R⁴Examples thereof include the compounds represented by the formula¹The same groups as those exemplified in (1). In addition, R in one molecule is preferable⁴At least two being alkenyl radicals, the other R⁴Is an alkyl group. The alkenyl group is preferably vinyl, and the alkyl group is preferably methyl. In addition, R⁴For example, 90% or more of (A) may be an alkyl group (preferably a methyl group). (D) The content of alkenyl groups in the organopolysiloxane is preferably, for example, 1.0 × 10^-6mol/g or more and 5.0X 10^-3mol/g or less, more preferably 5.0X 10^-6mol/g or more and 1.0X 10^-3mol/g is less than.

(D) The organopolysiloxane is preferably in a liquid state at 25 ℃, preferably has a viscosity of 100 to 1000000 mPas at 25 ℃, more preferably 200 to 100000 mPas. The average polymerization degree of the organopolysiloxane (D) is preferably 100 to 800, more preferably 150 to 600.

The organohydrogenpolysiloxane (E) is preferably a compound represented by the following average composition formula (3).

R⁵ _bH_cSiO_(4-b-c)/2...(3)

In the formula (3), b represents a positive number of 0.7 to 2.1, c represents a positive number of 0.001 to 1.0, and b-c is 0.8 to 3.0. In addition, R⁵Represents 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 to 10. Further, as R⁵Examples thereof include the compounds represented by the formula¹The same groups as those exemplified in (1).

(E) The organohydrogenpolysiloxane has 2 or more hydrogen atoms (Si — H) bonded to silicon atoms in one molecule, and preferably 3 or more. The number of hydrogen atoms bonded to silicon atoms in one molecule of the (E) organohydrogenpolysiloxane is preferably 200 or less, and more preferably 100 or less.

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

Examples of the organohydrogenpolysiloxane (E) include: methyl hydrogen polysiloxane with two terminal trimethylsiloxy groups sealed, dimethyl polysiloxane with two terminal dimethylsiloxy groups sealed, dimethyl siloxane-methyl hydrogen siloxane copolymer with two terminal dimethylsiloxy groups sealed, methyl hydrogen siloxane-diphenyl siloxane copolymer with two terminal trimethylsiloxy groups sealed, methyl hydrogen siloxane-diphenyl siloxane-dimethyl siloxane copolymer with two terminal trimethylsiloxy groups sealed, and a Copolymer of (CH) methyl hydrogen siloxane, diphenyl siloxane and dimethyl siloxane with two terminal trimethylsiloxy groups sealed₃)₂HSiO_1/2Unit and SiO_4/2A copolymer of units; and is Composed of (CH)₃)₂HSiO_1/2Unit, SiO_4/2Unit and (C)₆H₅)SiO_3/2Copolymers formed from units, and the like.

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

(F) The filler material may be, for example, an inorganic filler material. By blending (F) a filler in the addition curing type liquid conductive silicone rubber composition, the compression set is reduced, the volume resistivity is stabilized over time, and sufficient roller durability is obtained.

(F) The average particle diameter 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. When the average particle diameter of the filler (F) is 1 μm or more, the change with time in the volume resistivity is further suppressed. When the average particle size of the filler (F) is 30 μm or less, the elastic layer 3 having more excellent durability can be obtained. The average particle diameter of the filler (F) can be measured as a median particle diameter using a particle size distribution measuring apparatus based on a laser diffraction method.

(F) The packing material preferably has a bulk density of 0.1g/cm³Above and 0.5g/cm³Hereinafter, more preferably 0.15g/cm³Above and 0.45g/cm³The following. By adjusting the bulk density of the filler (F) to the above range, the compression set can be further reduced, the change with time in the volume resistivity can be further suppressed, and the elastic layer 3 having more excellent durability can be obtained. (F) The bulk density of the filler material can be determined according to the measurement method of the apparent specific gravity of JIS K6223.

Examples of the filler (F) include: diatomite, perlite, mica, calcium carbonate, glass flake, hollow filling materials and the like. Among these, pulverized products of diatomaceous earth, perlite, and expanded perlite are preferably used as the filler (F).

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 the (D) organopolysiloxane.

The blending amount of the (G) conductive material is preferably 0.5 parts by mass or more and 15 parts by mass or less, and more preferably 1 part by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the (D) organopolysiloxane.

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

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

The addition curing type liquid conductive silicone rubber composition may further contain additives other than (D) to (H). Examples of additives include: auxiliaries (chain extenders, crosslinking agents, etc.), foaming agents, dispersants, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, flame retardancy improvers, acid-absorbing agents, thermal conductivity improvers, mold release agents, diluents, reactive diluents, solvents, and the like.

Specific examples of the additives include low-molecular siloxane esters, polyether-modified silicone oils, and dispersants such as silanols and phenylsilane glycols. Further, heat resistance improvers such as iron octylate, iron oxide, and cerium oxide are exemplified. In addition, various carbon-functional silanes, various olefin elastomers, and the like can be used to improve adhesion, moldability, and the like. Further, a halogen compound or the like for imparting flame retardancy may be used.

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

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

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

In order to improve adhesion with the coating layer 4, the outer peripheral surface of the elastic layer 3 may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, excimer treatment, UV treatment, ITRO treatment, and flame treatment.

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

The elastic layer 3 may be formed on the outer circumferential surface of the shaft body 2 by a conventional molding method, by simultaneously or continuously performing thermosetting and molding. The method of curing the rubber composition may be any method as long as it can apply heat necessary for curing the rubber composition, and the method of molding the elastic layer 3 is not particularly limited, and may be, for example, continuous vulcanization by extrusion molding, molding by pressing or injection, or the like. For example, in the case where the rubber composition is an addition curing type kneaded conductive silicone rubber composition, extrusion molding or the like can be selected, and in the case where the rubber composition is an addition curing type liquid conductive silicone rubber composition, for example, a method using mold molding can be selected.

When the rubber composition is an addition curing type kneaded conductive silicone rubber composition, the heating temperature at the time of curing the rubber composition is preferably 100 ℃ or more and 500 ℃ or less, more preferably 120 ℃ or more and 300 ℃ or less. The heating time is preferably several seconds to 1 hour, more preferably 10 seconds to 35 minutes. When the rubber composition is an addition curing type liquid conductive silicone rubber composition, the heating temperature is preferably 100 ℃ or more and 300 ℃ or less, more preferably 110 ℃ or more and 200 ℃ or less. The heating time is preferably several seconds to 5 hours, more preferably 1 minute to 3 hours. Further, secondary vulcanization may be performed as necessary. When the rubber composition is an addition curing type kneaded conductive silicone rubber composition, for example, curing conditions of heating at 100 ℃ or higher and 200 ℃ or lower for 1 hour or longer and 20 hours or shorter are selected. In addition, when the rubber composition is an addition curing type liquid conductive silicone rubber composition, for example, curing conditions of heating at 120 ℃ or higher and 250 ℃ or lower for 2 hours or longer and 70 hours or shorter are selected. The rubber composition may be foamed and cured by a known method, and a sponge-like elastic layer having cells may be easily formed.

Other ingredients-

The rubber composition may further contain various additives other than the above additives. Examples of the various additives include: an auxiliary (chain extender, crosslinking agent, etc.), a catalyst, a dispersant, a foaming agent, an antiaging agent, an antioxidant, a pigment, a colorant, a processing aid, a softening agent, a plasticizer, an emulsifier, a heat resistance improver, a flame retardancy improver, an acid acceptor, a thermal conductivity improver, a mold release agent, a solvent, etc.

(coating layer)

The coating layer 4 is provided on the outer periphery of the elastic layer 3 and on the outermost surface of the developing roller 1. The coating layer 4 is formed by applying a composition (hereinafter referred to as a coating layer resin composition) on the outer peripheral surface of the elastic layer 3 or the primer layer formed as needed, and then heating and curing the applied coating layer resin composition.

The coating layer 4 of the present invention is formed by thermally curing a coating layer resin composition containing (a) a polyol containing at least one of (a1) a polyol having a non-reactive silicone group in a side chain and (a2) a one-terminal diol-type silicone oil, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material.

The respective components (a) to (d) of the resin composition for a coating layer will be described below.

(a) Polyhydric alcohols

The polyol may be any of various polyols generally used for the production of polyurethane, and is preferably at least one polyol selected from the group consisting of polyether polyol, polyester polyol, polyacrylate polyol, and polycarbonate polyol.

Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polypropylene glycol-ethylene glycol, polytetramethylene ether glycol, copolyols of tetrahydrofuran and an alkylene oxide, and various modifications thereof or mixtures thereof.

The polyester polyol has two or more ester groups and two or more hydroxyl groups in the molecule. Examples of the polyester polyol include condensation reaction products of dicarboxylic acids and polyhydric alcohols. As the dicarboxylic acid, for example, aromatic dicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid can be cited.

The polyacrylate polyol is a copolymer of a hydroxyl group-containing monomer and an ethylenically unsaturated monomer. Such as (meth) acrylates, styrene, a-methylstyrene, vinyltoluenes, vinyl esters, monoalkyl and dialkyl maleates, monoalkyl or dialkyl fumarates, a-olefins, unsaturated oligomers and copolymers of unsaturated polymers.

The polycarbonate polyol has two or more carbonate bonds and two or more hydroxyl groups in the molecule. Examples of the polycarbonate polyol include condensation reaction products of a polyol and a carbonate compound. Examples of the carbonate compound include: dialkyl carbonates, diaryl carbonates, alkylene carbonates, and the like. Examples of the polyol used as a raw material of the polycarbonate polyol include diols such as hexanediol and butanediol, and triols such as 2, 4-butanetriol.

The polyol preferably has a number average molecular weight of 500 or more and 8000 or less, more preferably 500 or more and 5000 or less, from the viewpoint of excellent compatibility with an isocyanate or the like described later. When the ionic liquid is a hydroxyl group-containing ionic liquid, it preferably has a number average molecular weight of 800 or more and 15000 or less, more preferably it has a number average molecular weight of 1000 or more and 5000 or less. The number average molecular weight is a molecular weight in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC).

(a) The polyol is a polyol containing at least one of (a1) a polyol having a non-reactive silicone group in a side chain and (a2) a single-ended glycol-type silicone oil.

Hereinafter, (a1) a polyol having a non-reactive silicone group in the side chain and (a2) a one-terminal diol-type silicone oil will be described.

(a1) Polyols having non-reactive organosilicon groups in side chains

Examples of the polyol having a non-reactive silicone group in a side chain of (a1) include silicone-grafted acrylic polyols containing constituent units represented by the following general formulae (1) and (2).

[ solution 1]

In the above general formulae (1) and (2), R¹Represents H or methyl. X is a divalent linking group having 1 to 12 carbon atoms. As the linking group, an alkylene group or an alkenylene group is preferable. R²Is an alkyl group having a hydroxyl group, wherein the number of carbon atoms in the alkyl group is 1 to 12 inclusive.

(a1) The number average molecular weight of the polyol having a non-reactive silicone group in a side chain is preferably 500 or more and 300000 or less.

(a1) The number average molecular weight of the organosilicon group in the polyol having a non-reactive organosilicon group on the side chain is preferably 500 or more and 100000 or less.

Further, the silicone group in the polyol having a non-reactive silicone group in the side chain (a1) is preferably 1% by mass or more and 50% by mass or less in the entire composition.

As a commercially available product of the polyol having a non-reactive silicone group in the side chain of (a1), there can be mentioned a silicone-grafted acrylic resin manufactured by shin-Etsu chemical Co., Ltd, trade name: X-24-798A, X-22-8004 (R4: C2H4OH, functional group equivalent: 3250(g/mol)), X-22-8009 (R4: an alkyl group containing Si (OCH3)3, functional group equivalent: 6200(g/mol)), X-22-8053 (R4: H, functional group equivalent: 900(g/mol)), X-22-8084EM, X-22-8195 (R4: H, functional group equivalent: 2700(g/mol)), Cymac series (US-GS 270, US-350, US-352, US-380, US-413, US-450, etc.) manufactured by Toyo Synthesis Co., Ltd., Rezeta-1000 series (GS-1015, GS-1302-GS, etc.), and the like.

(a2) Single-end diol type silicone oil

Examples of the silicone oil having a single-terminal diol type (a2) include those represented by the following general formula (3).

[ solution 2]

In the above general formula (3), R³And R⁶Is an alkyl group having 1 to 12 carbon atoms. R⁴Represents a single bond or an alkylene group having 1 to 12 carbon atoms.

(a2) The viscosity of the silicone oil with a single-terminal diol is preferably 130 to 550 (mm)²(s), the hydroxyl value is preferably 8 to 35 (mgKOH/g).

(a2) The molecular weight of the one-terminal diol-type silicone oil is preferably 3000 or more and 15000 or less.

Examples of commercially available products include X-22-176DX and X-22-176F, X-22-176GX-A manufactured by shin-Etsu chemical Co., Ltd.

(a1) The content of at least one of the polyol having a non-reactive silicone group in a side chain and the (a2) one-terminal diol-type silicone oil in the (a) polyol is preferably 2% by mass or more and 60% by mass or less, and more preferably 2% by mass or more and 30% by mass or less.

Of the (a1) polyol having a non-reactive silicone group in the side chain and (a2) single-terminal diol-type silicone oil, only the (a1) polyol having a non-reactive silicone group in the side chain is contained, and the (a1) polyol having a non-reactive silicone group in the side chain may be a silicone graft acrylic polyol. In this case, the content of the silicone-grafted acrylic polyol in the polyol is preferably 2 mass% or more and 40 mass% or less.

(a) The polyol may contain an acrylic monomer as a constituent unit in addition to at least one of (a1) and (a 2). Examples of the acrylic monomer include: acrylic acid, methyl acrylate, ethyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, 2-dimethylpropyl acrylate, cyclohexyl acrylate, 2-tert-butylphenyl acrylate, 2-naphthyl acrylate, phenyl acrylate, 4-methoxyphenyl acrylate, 2-methoxycarbonylphenyl acrylate, 2-ethoxycarbonylphenyl acrylate, 2-chlorophenyl acrylate, 4-chlorophenyl acrylate, benzyl acrylate, 2-cyanobenzyl acrylate, 4-cyanophenyl acrylate, p-tolyl acrylate, isononyl acrylate, 2-hydroxyethyl acrylate, di-n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, 2-dimethylpropyl acrylate, cyclohexyl acrylate, 2-tert-butylphenyl acrylate, 2-naphthyl acrylate, phenyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-cyanoethyl acrylate, 3-oxabutyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, 2-dimethylpropyl methacrylate, cyclohexyl methacrylate, 2-tert-butylphenyl methacrylate, 2-naphthyl methacrylate, phenyl methacrylate, 4-methoxyphenyl methacrylate, 2-methoxycarbonylphenyl methacrylate, 2-ethoxycarbonylphenyl methacrylate, ethyl methacrylate, octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, 2-naphthyl methacrylate, phenyl methacrylate, 4-methoxyphenyl methacrylate, 2-methoxycarbonylphenyl methacrylate, 2-ethoxycarbonylphenyl methacrylate, methyl methacrylate, 2-chlorophenyl methacrylate, 4-chlorophenyl methacrylate, benzyl methacrylate, 2-cyanobenzyl methacrylate, 4-cyanophenyl methacrylate, p-tolyl methacrylate, isononyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-cyanoethyl methacrylate, 3-oxabutyl methacrylate, gamma-methacryloxypropyltrimethoxysilane, acrylamide, butylacrylamide, N-dimethylacrylamide, piperidinylacrylamide, methacrylamide, 4-carboxyphenylmethacrylamide, 4-methoxycarbonylphenylphenylmethacrylamide, methyl chloroacrylate, ethyl-alpha-chloroacrylate, methyl methacrylate, 4-carboxyphenyl methacrylate, 2-cyanobenzyl methacrylate, 2-cyanophenyl methacrylate, 2-hydroxy-propyl methacrylate, 2-hydroxybutyl methacrylate, 2-cyanoethyl methacrylate, 2-hydroxy-propyl methacrylate, 2-hydroxy-, Propyl- α -chloroacrylate, isopropyl- α -chloroacrylate, methyl- α -fluoroacrylate, butyl- α -butoxycarbonylmethacrylate, butyl- α -cyanoacrylate, methyl- α -phenylacrylate, isobornyl acrylate, isobornyl methacrylate, diethylaminoethyl methacrylate, and the like. Copolymers of one or both of these materials are also possible.

(a1) The polyol having a non-reactive silicone group in a side chain is a compound represented by the above general formulae (1) and (2), and can be produced by radical copolymerization of an acrylic monomer in the presence of an azo polymerization initiator, if necessary. Such polymerization is preferably carried out by solution polymerization, bulk polymerization, emulsion polymerization or the like using a solvent, and particularly preferably by solution polymerization.

(b) Isocyanates

The isocyanate may be any of various isocyanates conventionally used for the production of polyurethanes, and examples thereof include aliphatic isocyanates, aromatic isocyanates and derivatives thereof. The isocyanate is preferably an aliphatic isocyanate from the viewpoint of excellent storage stability and easy control of the reaction rate.

Examples of the aromatic isocyanate include: xylylene Diisocyanate (XDI), diphenylmethane diisocyanate (MDI), tolylene diisocyanate (also referred to as tolylene diisocyanate TDI), 3, 3 '-dimethylbiphenyl-4, 4' -diisocyanate, 3, 3 '-dimethyldiphenylmethane-4, 4' -diisocyanate, 2, 4-tolylene diisocyanate uretdione (dimer of 2, 4-TDI), xylylene diisocyanate, Naphthalene Diisocyanate (NDI), p-Phenylene Diisocyanate (PDI), dimethylbiphenyl diisocyanate (TODI), m-phenylene diisocyanate, and the like.

Examples of the aliphatic isocyanate include: hexamethylene Diisocyanate (HDI), 4, 4 '-dicyclohexylmethane diisocyanate (hydrogenated MDI), o-toluidine diisocyanate, lysine diisocyanate methyl ester, isophorone diisocyanate (IPDI), norbornane diisocyanate methyl, trans-cyclohexane-1, 4-diisocyanate, triphenylmethane-4, 4' -triisocyanate, and the like.

Examples of the derivative include a polynuclear substance of polyisocyanate, a urethane-modified substance (including urethane prepolymer) modified with a polyol or the like, a dimer formed from uretdione, an isocyanurate-modified substance, a carbodiimide-modified substance, a uretonimine-modified substance, an allophanate (allophanate) -modified substance, a urea-modified substance, and a biuret-modified substance. One polyisocyanate may be used alone, or two or more of them may be used. The molecular weight of the polyisocyanate is preferably 500 to 2000, more preferably 700 to 1500.

The isocyanate (b) used in the resin composition for a coating layer is preferably a polyisocyanate. For example, a urethane type isocyanate, an adduct type isocyanate, or the like can be used. In particular, since the use of a blocked isocyanate can easily adjust the reaction rate, it is preferable.

(a) The mixing ratio of the polyol and polyisocyanate mixtures of (a1), (a2) and (a2) is not particularly limited, but generally the molar ratio (NCO/OH) of the hydroxyl group (OH) contained in the polyol to the isocyanate group (NCO) contained in the polyisocyanate is preferably 0.7 to 1.15. From the viewpoint of preventing hydrolysis of the polyurethane, the molar ratio (NCO/OH) is more preferably 0.85 or more and 1.10 or less. In practice, the amount of the compound is 3 to 4 times the above-mentioned suitable molar ratio in consideration of the working environment and the working error.

In the resin composition for a coating layer, an auxiliary agent usually used in the reaction between the polyol (a), (a1) and (a2) and the isocyanate (b), for example, a chain extender, a crosslinking agent, or the like, may be used in combination. Examples of the chain extender and the crosslinking agent include glycols, hexanetriol, trimethylolpropane, and amines.

(c) Surface roughness material

The coating layer 4 contains a surface roughness material. The surface roughness material is particles for adjusting the surface roughness of the coating layer 4. The average particle diameter of the surface roughness material blended in the coating layer 4 is 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 conveying performance is improved, and more excellent printing characteristics can be obtained. The average particle diameter of the surface roughness material may be measured as a median particle diameter using a particle size distribution measuring apparatus based on a laser diffraction method.

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

The type of the surface roughness material to be blended in the coating layer 4 is not particularly limited, and can be appropriately selected from conventional Filler materials (fillers) and used. For example, small-particle-diameter silica, spherical resin particles, metal oxides, and the like can be used.

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

(d) Conductive material

As the conductive material, a conductive agent having an electron conductive mechanism such as carbon black, graphite, copper, aluminum, nickel, iron powder, and a conductive metal oxide is preferable; conductive agents having an ion conductive mechanism such as alkali metal salts and quaternary ammonium salts; and a conductive agent having conductive composite particles, which is obtained by imparting conductive particles such as carbon black particles to the surface of silica particles.

As the conductive material, carbon black is particularly preferable. The carbon black is not particularly limited, and for example, acetylene black, furnace black, channel black, ketjen black, thermal black, and the like can be suitably used. As the carbon black, one of these may be used alone, or two or more of these may be used in combination. In order to obtain a desired resistance, two or more of various conductive agents may be used in combination.

The content of the conductive material in the resin composition for a coating layer is preferably 0.5 mass% or more and 20 mass% or less, more preferably 1.0 mass% or more and 15 mass% or less, and further preferably 2.0 mass% or more and 10 mass% or less, based on the total amount of the resin composition for a coating layer. By adjusting the content of the conductive material within the above range, the resistance value of the developing roller 1 is further stabilized, the printing performance is further improved, and the compression set of the elastic layer 3 is reduced, and the durability of the developing roller 1 is further improved.

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

The coating layer 4 is formed by applying a resin composition for a coating layer on the elastic layer 3, and polymerizing and curing at least one of (a) a polyol, (a1) a polyol having a non-reactive silicone group in a side chain thereof, and (a2) a one-terminal diol-type silicone oil 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 examples thereof include ethyl acetate and butyl acetate.

The coating of the resin composition for a coating layer is carried out by a conventional coating method, for example, a coating method of a coating liquid for coating the resin composition for a coating layer, an immersion method of immersing the elastic layer 3 or the like in the coating liquid, a spray method of spraying the coating liquid onto the elastic layer 3 or the like. The coating layer resin composition may be applied as it is, or a coating liquid may be prepared by adding a volatile solvent or water to the coating layer resin composition, and examples of the volatile solvent include: alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, and ester solvents such as ethyl acetate and butyl acetate. The method of curing the resin composition for a coating layer applied in the above manner may be any method as long as heat or moisture necessary for curing the resin composition for a coating layer can be applied, and examples thereof include a method of heating the elastic layer 3 or the like applied with the resin composition for a coating layer with a heater, and a method of leaving the elastic layer 3 or the like applied with the resin composition for a coating layer at a high humidity. When the resin composition for a coating layer is heat-cured, the heating temperature is, for example, preferably 100 ℃ or higher and 200 ℃ or lower, and more preferably 120 ℃ or higher and 160 ℃ or lower. The heating time is preferably 10 minutes to 120 minutes, more preferably 30 minutes to 60 minutes. Further, instead of coating, a method of laminating the resin composition for a coating layer on the outer peripheral surface of the elastic layer 3 or the primer layer by a conventional molding method such as extrusion molding, press molding, injection molding and the like while curing it, or a method of curing the laminated resin composition for a coating layer after lamination, and the like may be employed.

(other constitution)

The developing roller 1 of the present invention may be provided with intermediate layers 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 covering layer 4, by adjusting the electrical characteristics thereof, the electrical characteristics as the developing roller 1 can be adjusted, and thereby, the developing performance of the developing roller 1 can be satisfactorily adjusted.

As the primer layer, a primer layer generally used as a primer layer of the developing roller can be used, and for example, by forming a primer layer made of a urethane resin having an ester group, the developing performance of the developing roller 1 can be well maintained.

[ developing device and image Forming apparatus ]

The developing roller 1 according to the present embodiment can be suitably used as a developer carrier in a developing device and an image forming apparatus. In the present embodiment, the configuration of the image forming apparatus other than the developing roller 1 is not particularly limited. An example of a developing device and an image forming apparatus including the developing roller 1 of the present invention will be described with reference to fig. 2.

The image forming apparatus 10 is a tandem-type color image forming apparatus in which a plurality of

image carriers

11B, 11C, 11M, and 11Y each including a developing unit B, C, M and Y of each color are arranged in tandem on a transfer/conveyance belt 6, and a developing unit B, C, M and Y are arranged in tandem on the transfer/conveyance belt 6. The developing unit B includes: the image carrier 11B is, for example, a photoreceptor (also referred to as a photoreceptor drum), a charging mechanism 12B, for example, a charging roller, an exposure mechanism 13B, a developing device 20B, a transfer mechanism 14B, for example, a transfer roller, which is in contact with the image carrier 11B by the transfer and conveyance belt 6, and a cleaning mechanism 15B.

The developing device 20B is an example of the developing device of the present invention, and includes a developer 22B and the developing roller 1 of the present invention, as shown in fig. 2. Therefore, in the image forming apparatus 10, the developing roller 1 is mounted as the

developer carriers

23B, 23C, 23M, and 23Y. Specifically, the developing device 20B includes: a casing 21B that contains a one-component nonmagnetic developer 22B; and a developer carrier 23B, such as the developing roller 1, which supplies the developer 22B to the image carrier 11B; and a toner supply roller 25B that supplies the developer 22B to the developer carrier 23B; and a developer amount regulating mechanism 24B, such as a blade, which regulates the thickness of the developer 22B. In the developing device 20B, as shown in fig. 2, the developer amount regulating mechanism 24B is in contact with or pressure-contacted with the outer peripheral surface of the developer carrier 23B. That is, the developing device 20B is a so-called "contact developing device". The developing unit C, M and Y are constituted in substantially the same manner as the developing unit B, and the same elements are denoted by the same reference numerals and symbols C, M or Y indicating the respective units, and the description thereof will be omitted.

In the image forming apparatus 10, the developer carrier 23B of the developing device 20B is disposed so that the surface thereof is in contact with or pressed against the surface of the image carrier 11B. Similarly to the developing device 20B, the

developer carriers

23C, 23M, and 23Y of the developing

devices

20C, 20M, and 20Y are arranged such that the surfaces thereof are in contact with or in pressure contact with the surfaces of the

image carriers

11C, 11M, and 11Y. That is, the image forming apparatus 10 is a "contact image forming apparatus".

The fixing mechanism 30 is disposed downstream of the developing unit Y. The fixing mechanism 30 is a pressure heat fixing device including a fixing roller 31, an endless belt supporting roller 33 disposed in the vicinity of the fixing roller 31, an endless belt 36 wound around the fixing roller 31 and the endless belt supporting roller 33, and a pressure roller 32 disposed to face the fixing roller 31 in a casing 34 having an opening 35 through which the recording medium 16 passes, and is rotatably supported such that the fixing roller 31 and the pressure roller 32 are in contact with each other or in pressure contact with each other via the endless belt 36. At the bottom of the image forming apparatus 10, a cassette 41 for accommodating the recording body 16 is provided. The transfer conveyance belt 6 is wound around two or more support rollers 42.

The

developers

22B, 22C, 22M, and 22Y used in the image forming apparatus 10 may be dry developers or wet developers as long as they can be charged by friction, and may also be nonmagnetic developers or magnetic developers. In the

respective housings

21B, 21C, 21M, and 21Y of the developing units B, C, M and Y, a single-component non-magnetic black developer 22B, a cyan developer 22C, a magenta developer 22M, and a yellow developer 22Y are accommodated, respectively.

The image forming apparatus 10 forms a color image on the recording medium 16 as follows. First, in the developing unit B, an electrostatic latent image is formed by the exposure mechanism 13B on the surface of the image carrier 11B charged by the charging mechanism 12B, and the electrostatic latent image of black is developed by the developer 22B supplied from the developer carrier 23B. Then, while the recording body 16 passes between the transfer mechanism 14B and the image carrier 11B, the electrostatic latent image of black is transferred to the surface of the recording body 16. Next, in the same manner as the developing unit B, a cyan image, a magenta image, and a yellow image are superimposed on the recording body 16, in which the electrostatic latent image is visualized into a black image, by the developing units C, M and Y, respectively, so that a color image is visualized. Next, the recording medium 16 on which the color image is developed is fixed as a permanent image on the recording medium 16 by the fixing mechanism 30. In this way, a color image can be formed on the recording body 16.

The developing device 20B includes the developing roller 1, has excellent developer conveyance performance, can suppress the occurrence of toner filming, and contributes to forming images with high density and high image quality for a long time. In addition, the image forming apparatus 10 can form high-density and high-quality images for a long time.

The developing device and the image forming apparatus of the present invention are not limited to the above examples, and various modifications may be made within a range that can achieve the object of the present invention.

Although the image forming apparatus is an electrophotographic image forming apparatus, in the present invention, the image forming apparatus is not limited to the electrophotographic system, and may be, for example, an electrostatic image forming apparatus. The image forming apparatus provided with the developing roller according to the present invention is not limited to a tandem type color image forming apparatus in which a plurality of image bearing members each having a developing unit of each color are arranged in series on a transfer belt, and may be, for example, a monochrome image forming apparatus having a single developing unit, a four-cycle type color image forming apparatus in which a developer image borne on an image bearing member is repeatedly and primarily transferred onto an endless belt in sequence, or the like. In addition, although the developer used in the image forming apparatus is a one-component non-magnetic developer, in the present invention, it may be a one-component magnetic developer, a two-component non-magnetic developer, or a two-component magnetic developer.

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

The present invention has been described above with reference to the embodiments, but the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments, and it is obvious to those skilled in the art that various changes and modifications can be made to the above embodiments. It is apparent from the description of the claims that the invention having the above modifications or improvements can be included in the technical scope of the present invention.

Examples

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

[ example 1]

(formation of primer layer)

The shaft body (made of SUM22, diameter 10mm, length 275mm) subjected to electroless nickel plating was cleaned with ethanol, and a silicone PRIMER (trade name "PRIMER No. 16", manufactured by shin-Etsu chemical Co., Ltd.) was applied to the surface thereof. The shaft body treated with the primer was baked at 150 ℃ for 10 minutes using a gill 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 body.

(formation of elastic layer)

Then, for example, inThe silicone rubber composition for forming the elastic layer was prepared as described below. That is, 100 parts by mass of dimethylpolysiloxane having both terminals blocked with dimethylvinylsiloxane groups (degree of polymerization 300) and 1 part by mass of BET specific surface area of 110m²40 parts by mass of a hydrophobized fumed silica (trade name: R-972; manufactured by NIPPON AEROSIL Co., Ltd.) having an average particle diameter of 6 μm and a bulk density of 0.25g/cm³The diatomaceous earth (trade name "Oplite W-3005S", manufactured by Chuo Silika K.K.) and 5 parts by mass of acetylene BLACK (trade name "DENKA BLACK HS-100", manufactured by Denka K.K.) were charged into a planetary mixer, stirred for 30 minutes, and then passed through a three-roll mill once. This was returned again to the planetary mixer, and 2.1 parts by mass of methylhydrogenpolysiloxane having both terminals and a side chain having an Si — H group (polymerization degree 17, Si — H amount 0.0060mol/g), 0.1 part by mass of ethynylcyclohexanol, and 0.1 part by mass of platinum-based catalyst (Pt concentration 1% by mass) were added, and the mixture was stirred, defoamed, and kneaded for 30 minutes to prepare an addition curing type liquid conductive silicone rubber composition.

The prepared addition curing type liquid conductive silicone rubber composition was injection-molded using a mold to form an elastomer made of a rubber material on the outer peripheral surface of the shaft body. In injection molding, an addition curing type liquid conductive silicone rubber composition was heated at 120 ℃ for 10 minutes to be cured, and subjected to secondary vulcanization at 200 ℃ for 4 hours, thereby forming 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.

Resin composition for coating layer

(a) Polycarbonate diol (product name "Nipporan 981" manufactured by Tosoh corporation) was 95.4 parts by mass

(a1) 4.6 parts by mass of a silicone-grafted acrylic polyol

(b) The urethane-type isocyanate (product name "TPA-B80E" manufactured by Asahi Kasei K.K.) was 49.6 parts by mass

(c) The surface roughness material (AEROSIL (registered trademark) R711, manufactured by AEROSIL co., ltd., japan) was 13.5 parts by mass

(d) The conductive material (MA600, manufactured by Mitsubishi chemical Strand group) was 3 parts by mass

< Synthesis of siloxane-grafted acrylic polyol (a1) >

(a1) Silicone-grafted acrylic polyol was prepared by radical polymerizing the compounds represented by the above general formulae (1) and (2) in the presence of Azobisisobutyronitrile (AIBN).

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 ℃ for 30 minutes to form a coating layer having a layer thickness of 20 μm. In this way, a developing roller having a shaft body, an elastic layer, and a coating layer was produced.

Examples 2 to 7 and comparative examples 1 to 3

Using the materials and compounding ratios shown in table 1, a developing roller was produced in the same manner as in example 1.

In Table 1, (a) POLYCASTOR #10 manufactured by Ito oil corporation was used as the polyester polyol, (a2) X-22-176DX manufactured by shin-Etsu chemical Co., Ltd was used as the one-terminal diol type silicone oil, and Duranate E402-B80B manufactured by Asahi Kasei corporation was used as the adduct type isocyanate.

[ evaluation ]

An image forming apparatus HL-3170CDW (model, manufactured by Brother Industries, ltd.) was prepared, and the developing roller of the image forming apparatus was replaced with the developing roller of each of the examples and comparative examples to obtain an image forming apparatus. The obtained image forming apparatus was evaluated for the coefficient of dynamic friction, the coefficient of static friction, and the banding by the following methods.

(coefficient of dynamic Friction and coefficient of static Friction)

The developing roller thus manufactured was measured a plurality of times in the longitudinal direction of the roller under a load of 300N by using an i-tester TL701(R contactor) manufactured by Trinity Lab corporation, and the arithmetic mean value thereof was determined as the static friction coefficient and the dynamic friction coefficient of each test piece.

(strip evaluation)

Each of the manufactured conductive rollers was mounted as a developing roller to a contact type image forming apparatus HL-3170CDW (model, manufactured by Brother Industries, ltd.) and allowed to stand at 23 ℃ for 24 hours in a normal temperature and humidity environment of 50%. Then, a halftone image was printed on a4 paper (JIS) while maintaining the normal temperature and humidity environment. In the printed halftone image, the band at the same level as that of the conventional product was evaluated as "C", and the case where the sufficient improvement of the band was observed was evaluated as "a".

In the above-described image area, the high-density portion extending in the short side direction of the a4 paper is a stripe. In the evaluation of the banding, as the developer and developer amount adjusting mechanism, the developer and developer amount adjusting mechanism mounted on the image forming apparatus was used.

The evaluation results are shown in table 1.

[ Table 1]

As shown in table 1, in examples containing (a1) a polyol having a non-reactive silicone group in the side chain or (a2) a single-ended glycol-type silicone oil as a raw material of the coating layer resin composition, the coefficient of dynamic friction and the coefficient of static friction were both lower than those of the comparative examples, and thus the improvement in the band was observed.

This is considered to be because the silicone chain in (a1) is a non-reactive group and (a2) is a single-ended silicone chain, and the silicone chain is not incorporated into the polyurethane as a main chain but is present on the surface of the coating layer as a side chain having a relatively high degree of freedom, and therefore the friction coefficient can be reduced.

Description of the reference numerals

1 developing roller

2 axle body

3 elastic layer

4 coating layer

6 transfer printing conveyer belt

10 image forming apparatus

11B, 11C, 11M, 11Y image carrier

12B, 12C, 12M, 12Y charging mechanism

13B, 13C, 13M, 13Y exposure mechanism

14B, 14C, 14M, 14Y transfer mechanism

15B, 15C, 15M, 15Y cleaning mechanism

16 recording medium

20B, 20C, 20M, 20Y developing device

21B, 21C, 21M, 21Y, 34 box

22B, 22C, 22M, 22Y developer

23B, 23C, 23M, 23Y developer carrier (developing roller)

24B, 24C, 24M, 24Y developer amount regulating mechanism

25B, 25C, 25M, 25Y toner supply roller

30 fixing mechanism

31 fixing roller

32 pressure roller

33 endless belt support roller

35 opening part

36 annular band

41 cassette

42 support roller

B. C, M, Y developing unit

Claims

1. A developing roller is provided with:

an elastic layer formed on an outer peripheral surface of the shaft body; and

a coating layer formed on an outer peripheral surface of the elastic layer;

wherein the coating layer is formed by thermally curing a coating layer resin composition containing (a) a polyol, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material;

the polyol (a) contains at least one of a polyol (a1) having a non-reactive silicone group in a side chain and a silicone oil (a2) having a single-ended glycol group.

2. The developer roller according to claim 1, wherein

The content of at least one of the polyol having a non-reactive silicone group in the side chain of the polyol (a1) and the single-ended glycol silicone oil (a2) in the polyol (a) is 2 to 600 mass%.

3. The developing roller according to claim 1 or 2, wherein,

in the polyol having a non-reactive silicone group in the (a1) side chain and the (a2) one-terminal diol-type silicone oil, only the polyol having a non-reactive silicone group in the (a1) side chain is contained, and the polyol having a non-reactive silicone group in the (a1) side chain is a silicone grafted acrylic polyol.

4. The developer roller according to claim 3, wherein,

the content of the silicone-grafted acrylic polyol in the polyol (a) is 2 to 40 mass%.

5. A developing device, wherein,

the developing roller according to any one of claims 1 to 4.

6. An image forming apparatus in which, when a toner image is formed,

the developing roller according to any one of claims 1 to 4.