CN112955824B - Developing roller, developing device, and image forming apparatus - Google Patents

Developing roller, developing device, and image forming apparatus Download PDF

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Publication number
CN112955824B
CN112955824B CN201980071075.XA CN201980071075A CN112955824B CN 112955824 B CN112955824 B CN 112955824B CN 201980071075 A CN201980071075 A CN 201980071075A CN 112955824 B CN112955824 B CN 112955824B
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Prior art keywords
polyol
mass
coating layer
developing roller
silicone
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CN201980071075.XA
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CN112955824A (en
Inventor
加藤慧
广谷泰男
高梨寛之
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Shin Etsu Polymer Co Ltd
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Shin Etsu Polymer Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/61—Polysiloxanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/62—Polymers of compounds having carbon-to-carbon double bonds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L75/00—Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
    • C08L75/04—Polyurethanes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer

Abstract

A developing roller (1) is provided with 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 resin composition for coating layer containing (a) a polyol, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material; wherein (a) the polyol contains at least one of (a 1) a polyol having a non-reactive silicone group in a side chain and (a 2) a single-terminal diol type silicone oil.

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, a facsimile machine, and the like employing an electrophotographic system has a property of transporting 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 printing 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 rotates in the same direction in a state of contact with the photosensitive drum, and generates a speed difference, thereby causing toner to adhere to the photosensitive drum. Therefore, if the smoothness of the surface of the developing roller 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 belt-like shadow, so-called a belt, appears in the image.
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above-described 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.
Technical means for solving the problems
The inventors of the present invention have conducted intensive studies on a resin used for a coating layer in order to eliminate the sticking of a developing roller to a photosensitive drum, and have found that the banding can be improved by incorporating a specific polyol in a regulating component of a urethane resin for 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 the outer peripheral surface of the shaft body; and a coating layer formed on the 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 (a 1) a polyol having a non-reactive silicone group in a side chain and (a 2) a single-terminal diol type silicone oil.
(a) The content of at least one of (a 1) a polyol having a non-reactive silicone group in a side chain and (a 2) a single-terminal diol type silicone oil in the polyol is preferably 2% by mass or more and 60% by mass or less.
Among the (a 1) polyol having a non-reactive silicone group in a side chain and the (a 2) one-terminal diol type silicone oil, only the (a 1) polyol having a non-reactive silicone group in a side chain is contained, and the (a 1) polyol having a non-reactive silicone group in a side chain is preferably a silicone grafted acrylic polyol.
In the above case, the content of the silicone-grafted acrylic polyol in the polyol (a) is preferably 2% by mass or more and 40% by mass or less.
Another embodiment of the present invention is a developing device including the developing roller of the above embodiment.
Another embodiment of the present invention is an image forming apparatus including the developing roller of the above embodiment.
Effects of the invention
According to the present invention, a developing roller, a developing device, and an image forming apparatus can be provided in which a belt can be suppressed well.
Drawings
Fig. 1 is a schematic perspective view showing an embodiment of the developing roller of the present invention.
Fig. 2 is a schematic cross-sectional view showing an embodiment of the image forming apparatus of the present invention.
Description of the reference numerals
1. Developing roller
2. Shaft body
3. Elastic layer
4. Coating layer
6. Transfer conveyor belt
10. Image forming apparatus having a plurality of image forming units
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 adjusting mechanism
25B, 25C, 25M, 25Y toner supply roller
30. Fixing mechanism
31. Fixing roller
32. Pressure roller
33. Annular belt supporting roller
35. An opening part
36. Endless belt
41. Cassette
42. Supporting roller
B. C, M, Y developing unit
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail, but the following embodiments are provided for the purpose of example, and the present invention is not limited to the embodiments shown below.
[ developing roller ]
Fig. 1 is a schematic perspective view showing an embodiment of the developing roller of the present invention.
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 following describes the structure of the developing roller 1 of the present invention.
(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 composed of at least one metal selected from the group consisting of iron, aluminum, stainless steel, and brass, for example. Such a shaft body 2 composed of metal is also commonly referred to as "core gold".
The shaft body 2 may contain an insulating resin. The insulating resin may be, for example, a thermoplastic resin or a thermosetting resin. The shaft body 2 may include a core body formed of, for example, an insulating resin and a plating layer provided on the core body. Such a shaft body 2 can be obtained, for example, by electroplating a core body formed of an insulating resin to make it conductive.
The shaft body 2 is preferably core gold to obtain good conductive properties.
The shaft body 2 is preferably shaped like a rod, a tube, or the like. The cross-sectional shape of the shaft body 2 may be circular or elliptical, or may be non-circular, such as polygonal. On the outer peripheral surface of the shaft body 2, a treatment such as a cleaning treatment, a degreasing treatment, a primer treatment, or the like may be performed to improve adhesion with the elastic layer 3.
The axial length of the shaft 2 is not particularly limited, and can be appropriately adjusted according to the form of the image forming apparatus to be mounted. 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, more preferably 260mm or more and 310mm or less. The diameter of the shaft body 2 (diameter of the circumscribed circle) is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be mounted. For example, the outer diameter (diameter of the circumscribed circle) of the shaft body 2 is preferably 4mm or more and 14mm or less, more preferably 6mm or more and 10mm or less.
(elastic layer)
The elastic layer 3 is formed by heating and curing the rubber composition on the outer peripheral surface of the shaft body 2. The rubber composition for forming the elastic layer 3 preferably contains 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. The silicone or silicone-modified rubber or urethane rubber is preferable, and particularly preferable is silicone or silicone-modified rubber because it is capable of reducing 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 dimethylpolysiloxane and diphenylpolysiloxane.
Examples of the silicone rubber composition include an addition-curable kneaded conductive silicone rubber composition, an addition-curable liquid conductive silicone rubber composition, and the like.
Addition-curable kneaded conductive silicone rubber composition
The addition-curable kneaded conductive silicone rubber composition may be, for example, a composition containing (a) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C) a conductive material.
R 1 n SiO (4-n)/2 ...(1)
In the formula (1), n represents a positive number of 1.95 to 2.05. In addition, R 1 Represents a substituted or unsubstituted monovalent hydrocarbon group, which may be the same or different. The number of carbon atoms of the hydrocarbon group is preferably 1 to 12, more preferably 1 to 8.
As R 1 Examples thereof include: alkyl groups such as methyl, ethyl, propyl, butyl, hexyl and dodecyl, cycloalkyl groups such as cyclohexyl, alkenyl groups such as vinyl, allyl, butenyl and hexenyl, aryl groups such as phenyl and tolyl, aralkyl groups such as β -phenylpropyl, and the like. In addition, R 1 The hydrocarbon groups may have a part or all of hydrogen atoms substituted with substituents. The substituent may be, for example, a halogen atom, a cyano group or the like. Having substituentsThe hydrocarbon group is, for example, chloromethyl, trifluoropropyl, cyanoethyl, etc.
(A) The organopolysiloxane is preferably blocked at the molecular chain end by a trialkylsilyl group such as trimethylsilyl group, a dialkylaralkylsilyl group such as dimethylvinylsilyl group, a dialkylhydroxysilyl group such as dimethylhydroxysilyl group, and a triarylalkylsilyl group such as trivinylsilyl group.
(A) The organopolysiloxane preferably has two or more alkenyl groups in the molecule. (A) The organopolysiloxane is preferably R 1 Has 0.001 mol% or more and 5 mol% or less (more preferably 0.01 mol% or more and 0.5 mol% or less) of alkenyl groups. Vinyl groups are particularly preferred as 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 cyclic polysiloxanes such as trimers or tetramers of siloxanes. (A) The organopolysiloxane may be a substantially linear diorganopolysiloxane or may be partially branched. (A) The organopolysiloxane may be a mixture of two or more kinds different in molecular structure.
(A) The organopolysiloxane preferably has a kinematic viscosity at 25 ℃ of 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, more preferably 3000 or more and 10000 or less.
As the filler (B), for example, a silica-based filler can be cited. Examples of the silica-based filler include fumed silica and precipitated silica.
As the silica-based filler, a filler of the general formula R is preferably used 2 Si(OR 3 ) 3 The surface-treated silica filler having a surface-treated silane coupling agent is provided. Here, R is 2 It may be a group having a vinyl group or an amino group, such as a glycidyl group, a vinyl group, an aminopropyl group, a methacryloxy group, an N-phenylaminopropyl group, a mercapto group, or the like. R is R 3 It may be an alkyl group which may be a hydrocarbon group,such as methyl, ethyl, and the like. The silane coupling agent is readily available, for example, under the trade names "KBM1003" and "KBE402" manufactured by Xinyue chemical industries, inc. 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, commercially available products can be used, and examples thereof include the trade name "Zeothix 95" manufactured by J.M. HUBER Co.
The amount of the silica filler to be blended is preferably 11 parts by mass or more and 39 parts by mass or less, more preferably 15 parts by mass or more and 35 parts by mass or less, per 100 parts by mass of the organopolysiloxane (a). The average particle diameter of the silica filler is preferably 1 μm or more and 80 μm or less, more preferably 2 μm or more and 40 μm or less. The average particle diameter of the silica filler can be measured as a median particle diameter using a particle size distribution measuring apparatus based on a laser diffraction method.
The amount of the conductive material (C) to be blended is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, per 100 parts by mass of the organopolysiloxane (a). The amount of the conductive material (C) to be blended is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of the organopolysiloxane (a).
The addition-curable kneaded conductive silicone rubber composition may further contain additives other than (a) to (C). Examples of such additives include: auxiliary agents (chain extenders, cross-linking agents, etc.), catalysts, dispersants, foaming agents, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, flame resistance improvers, acid absorbers, thermal conductivity improvers, mold release agents, solvents, etc.
Specific examples of the additive include: a low molecular weight silicone having a degree of polymerization lower than that of the organopolysiloxane (A), a dimethylsiloxane oil, a polyether-modified silicone oil, a silanol, a diphenylsilanol, an alpha, omega-dimethylsiloxane diol or the like, and a dispersant such as a silane. Specific examples of the additive include: and heat resistance improvers such as iron octoate, 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, molding processability, and the like.
Addition-curable liquid conductive silicone rubber composition
The addition-curable liquid electroconductive 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 organohydrogen polysiloxane containing two or more silicon-bonded hydrogen 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).
R 4 a SiO (4-a)/2 ...(2)
In the formula (2), a represents a positive number of 1.5 to 2.8, preferably 1.8 to 2.5, more preferably 1.95 to 2.05. In addition, R 4 Represents a substituted or unsubstituted monovalent hydrocarbon group, which may be the same or different. However, R of one molecule 4 At 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 R 4 Can be mentioned as R 1 The same groups as exemplified in (a) are the same groups. In addition, R in one molecule is preferable 4 At least two are alkenyl groups, the others R 4 Is an alkyl group. Alkenyl is preferably vinyl and alkyl is preferably methyl. In addition, R 4 For example, 90% or more of the groups may be alkyl groups (preferably methyl groups). (D) The alkenyl group content in the organopolysiloxane is, for example, preferably 1.0X10 -6 mol/g or more and 5.0X10 -3 mol/g or less, more preferably 5.0X10 -6 mol/g or more and 1.0X10 -3 mol/g or less.
(D) The organopolysiloxane is preferably in a liquid state at 25 ℃, preferably has a viscosity of 100mpa·s to 1000000mpa·s, more preferably 200mpa·s to 100000mpa·s at 25 ℃. The average polymerization degree of the organopolysiloxane (D) is preferably 100 to 800, more preferably 150 to 600.
The organohydrogen polysiloxane (E) is preferably a compound represented by the following average composition formula (3).
R 5 b H c SiO (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, R 5 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 to 10. In addition, as R 5 Can be mentioned as R 1 The same groups as exemplified in (a) are the same groups.
(E) The organohydrogen polysiloxane has 2 or more hydrogen atoms (si—h) bonded to silicon atoms in one molecule, preferably 3 or more. The number of hydrogen atoms bonded to silicon atoms in one molecule of the (E) organohydrogen polysiloxane is preferably 200 or less, more preferably 100 or less.
In the organohydrogensilicon polysiloxane of (E), 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 organohydrogen polysiloxane (E) include: methyl hydrogen polysiloxane with two ends being blocked by trimethylsiloxy, dimethyl polysiloxane with two ends being blocked by dimethylsiloxy, dimethyl siloxane methyl hydrogen siloxane copolymer with two ends being blocked by dimethylsiloxy, methyl hydrogen siloxane diphenyl siloxane copolymer with two ends being blocked by trimethylsiloxy, methyl hydrogen siloxane diphenyl siloxane dimethyl siloxane copolymer with two ends being blocked by trimethylsiloxy, and preparation method thereof 3 ) 2 HSiO 1/2 Unit and SiO 4/2 A copolymer of units; and is formed by (CH) 3 ) 2 HSiO 1/2 Unit, siO 4/2 Unit sum (C) 6 H 5 )SiO 3/2 Formed of unitsCopolymers, and the like.
The amount of the organohydrogen polysiloxane (E) to be blended is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 0.3 part by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the organopolysiloxane (D). The molar ratio of Si-H of the (E) organopolysiloxane to alkenyl of the (D) organopolysiloxane 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) the filler into the addition-curable liquid conductive silicone rubber composition, compression set is reduced, volume resistivity is stabilized with 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, 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 in volume resistivity with time is further suppressed. In addition, when the average particle diameter 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 bulk density of the filler material is preferably 0.1g/cm 3 Above and 0.5g/cm 3 Hereinafter, more preferably 0.15g/cm 3 Above and 0.45g/cm 3 The following is given. By adjusting the bulk density of the filler (F) to the above range, compression set can be further reduced, the change in volume resistivity with time can be further suppressed, and the elastic layer 3 having more excellent durability can be obtained. (F) The bulk density of the filler may be determined according to the method of measuring the apparent specific gravity of JIS K6223.
Examples of the filler (F) include: diatomaceous earth, perlite, mica, calcium carbonate, glass flakes, hollow filler materials, and the like. Among them, as the filler (F), pulverized materials of diatomaceous earth, perlite and expanded perlite are preferably used.
The amount of the filler (F) to be blended is preferably 5 parts by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the organopolysiloxane (D).
The amount of the conductive material (G) to be blended is preferably 0.5 parts by mass or more and 15 parts by mass or less, more preferably 1 part by mass or more and 10 parts by mass or less, per 100 parts by mass of the organopolysiloxane (D).
(H) The addition reaction catalyst may be any catalyst capable of activating the addition reaction of (D) organopolysiloxane and (E) organohydrogen polysiloxane. Examples of the catalyst for the addition reaction (H) include catalysts containing a platinum group element. Examples of the catalyst having a platinum group element include platinum-based catalysts (e.g., platinum black, platinum chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and an olefin, platinum diacetylacetate, etc.), palladium-based catalysts, rhodium-based catalysts, and the like.
(H) The addition reaction catalyst may be added in an amount of 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, relative to the total mass of the organopolysiloxane (D) and the organopolysiloxane (E).
The addition-curable liquid conductive silicone rubber composition may further contain additives other than (D) to (H). Examples of the additive include: adjuvants (chain extenders, crosslinkers, etc.), foaming agents, dispersants, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, flame resistance improvers, acid absorbers, thermal conductivity improvers, mold release agents, diluents, reactive diluents, solvents, etc.
Specific examples of the additives include dispersants such as low molecular weight silicone esters, polyether modified silicone oils, silanol and phenylsilanediol. Further, heat resistance improvers such as iron octoate, iron oxide, and cerium oxide can be mentioned. In addition, various carbon functional silanes, various olefin elastomers, etc. can be used to improve adhesion, molding processability, etc. In addition, a halogen compound or the like imparting flame retardancy may also be used.
The viscosity of the addition-curable liquid electroconductive silicone rubber composition at 25 ℃ is preferably 5pa·s to 500pa·s, more preferably 5pa·s to 200pa·s.
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 the present 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 to 25mm, more preferably 7mm to 21 mm.
In order to improve the adhesion to the coating layer 4, the outer peripheral surface of the elastic layer 3 may be subjected to surface treatments 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 a method such as extrusion molding of a silicone rubber composition, LIMS molding, or the like. The elastic layer 3 may be formed by grinding or polishing an 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 heat curing and molding. The method of curing the rubber composition may be any method as long as it is a method capable of applying heat required for curing the rubber composition, and the molding method of the elastic layer 3 is not particularly limited, and for example, continuous vulcanization by extrusion molding, molding by pressing, injection molding, or the like may be used. For example, when the rubber composition is an addition-curable kneaded conductive silicone rubber composition, extrusion molding or the like may be selected, and when the rubber composition is an addition-curable liquid conductive silicone rubber composition, a method using a mold molding may be selected, for example.
When the rubber composition is an addition-curable kneaded conductive silicone rubber composition, the heating temperature at the time of curing the rubber composition is preferably 100 ℃ or higher and 500 ℃ or lower, more preferably 120 ℃ or higher and 300 ℃ or lower. The heating time is preferably several seconds to 1 hour, more preferably 10 seconds to 35 minutes. When the rubber composition is an addition-curable liquid conductive silicone rubber composition, the heating temperature is preferably 100 ℃ or higher and 300 ℃ or lower, more preferably 110 ℃ or higher and 200 ℃ or lower. The heating time is preferably several seconds to 5 hours, more preferably 1 minute to 3 hours. In addition, secondary vulcanization may be performed as needed. When the rubber composition is an addition-curable kneaded conductive silicone rubber composition, curing conditions are selected such as heating at 100 ℃ or more and 200 ℃ or less for 1 hour or more and 20 hours or less. In addition, when the rubber composition is an addition-curable liquid conductive silicone rubber composition, curing conditions are selected such as heating at 120 ℃ or more and 250 ℃ or less for 2 hours or more and 70 hours or less. The rubber composition may be foamed and cured by a known method, and a foam-like elastic layer having bubbles 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: auxiliary agents (chain extenders, cross-linking agents, etc.), catalysts, dispersants, foaming agents, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, heat resistance improvers, flame resistance improvers, acid absorbers, thermal conductivity improvers, mold release agents, solvents, 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 a 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 (a 1) a polyol having a non-reactive organosilicon group in a side chain and (a 2) a one-terminal diol type silicone oil, (b) an isocyanate, (c) a surface roughness material, and (d) a conductive material.
The components (a) to (d) of the coating resin composition will be described below.
(a) Polyhydric alcohol
The polyol may be any of various polyols generally used for the production of polyurethane, and is preferably at least one polyol selected from polyether polyols, polyester polyols, polyacrylate polyols and polycarbonate polyols.
Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polypropylene glycol-ethylene glycol, polytetramethylene ether glycol, copolymerized polyols of tetrahydrofuran and 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 polyols. 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 copolymers of hydroxyl-containing monomers and olefinically unsaturated monomers. Such as (meth) acrylates, styrene, a-methylstyrene, vinyltoluene, vinyl esters, monoalkyl and dialkyl maleates, monoalkyl fumarates or dialkyl fumarates, a-olefins, unsaturated oligomers and copolymers of unsaturated polymers.
The polycarbonate polyol has two or more carbonate linkages 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, triols such as 2, 4-butanetriol, and the like.
From the viewpoint of excellent compatibility with isocyanate and the like described later, 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. 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 the molecular weight as measured by Gel Permeation Chromatography (GPC) in terms of standard polystyrene.
(a) The polyol is a polyol containing at least one of (a 1) a polyol having a non-reactive silicone group in a side chain and (a 2) a single-terminal diol type silicone oil.
Next, (a 1) a polyol having a non-reactive silicone group in a side chain and (a 2) a single terminal diol type silicone oil will be described.
(a1) Polyols having non-reactive organosilicon groups in the side chains
Examples of the polyol having a non-reactive silicone group in the side chain of (a 1) include silicone grafted acrylic polyols containing constituent units represented by the following general formulae (1) and (2).
[ chemical 1]
In the above general formulae (1) and (2), R 1 Represents H or methyl. X is a divalent linking group having 1 to 12 carbon atoms. As the linking group, alkylene or alkenylene is preferable. R is R 2 Is an alkyl group having a hydroxyl group, and the number of carbon atoms of the alkyl group is 1 to 12.
(a1) The number average molecular weight of the polyol having a non-reactive silicone group in a side chain is preferably 500 to 300000.
(a1) The number average molecular weight of the silicone group in the polyol having a non-reactive silicone group in a side chain is preferably 500 to 100000.
Further, the silicone group in the polyol having a non-reactive silicone group in the side chain of (a 1) is preferably 1% by mass or more and 50% by mass or less in the entire composition.
As the commercial product of the polyol having a non-reactive silicone group in the side chain of (a 1), there can be mentioned a silicone grafted acrylic resin manufactured by Xinyue chemical industry Co., ltd., trade name: X-24-798A, X-22-8004 (R4: C2H4OH, functional equivalent: 3250 (g/mol)), X-22-8009 (R4: alkyl group containing Si (OCH 3) 3, functional equivalent: 6200 (g/mol)), X-22-8053 (R4: H, functional equivalent: 900 (g/mol)), X-22-8084EM, X-22-8195 (R4: H, functional equivalent: 2700 (g/mol)), cymac series (US-270, US-350, US-352, US-380, US-413, US-450, etc.), rezeta GS-1000 series (GS-1015, GS-1302, etc.), and the like manufactured by Toyaki Co.
(a2) Single-terminal glycol type silicone oil
Examples of the (a 2) single-terminal diol type silicone oil include those represented by the following general formula (3).
[ chemical 2]
In the above general formula (3), R 3 R is as follows 6 Is an alkyl group having 1 to 12 carbon atoms. R is R 4 Represents a single bond or an alkylene group having 1 to 12 carbon atoms.
(a2) The viscosity of the single-terminal glycol-type silicone oil is preferably 130 to 550 (mm) 2 Preferably, the hydroxyl value is 8 or more and 35 or less (mgKOH/g).
(a2) The molecular weight of the single-terminal glycol-type silicone oil is preferably 3000 to 15000.
Examples of the commercial products include X-22-176DX and X-22-176F, X-22-176GX-A manufactured by Xinyue chemical industries, inc.
(a1) The content of at least one of the polyol having a non-reactive silicone group in a side chain and (a 2) the one-terminal diol type silicone oil in (a) the polyol is preferably 2% by mass or more and 60% by mass or less, more preferably 2% by mass or more and 30% by mass or less.
Among the (a 1) polyol having a non-reactive silicone group in a side chain and the (a 2) one-terminal diol type silicone oil, only the (a 1) polyol having a non-reactive silicone group in a side chain, and the (a 1) polyol having a non-reactive silicone group in a side chain may be a silicone grafted acrylic polyol. In this case, the content of the silicone-grafted acrylic polyol in the polyol is preferably 2% by mass or more and 40% by mass or less.
(a) The polyhydric alcohol may contain an acrylic monomer as a constituent unit in addition to at least one of (a 1) 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 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, t-butyl methacrylate, 2-dimethylpropyl methacrylate, cyclohexyl methacrylate, 2-t-butylphenyl methacrylate, 2-naphthyl methacrylate, phenyl methacrylate, 4-methoxyphenyl methacrylate, 2-methoxycarbonylphenyl methacrylate, 2-ethoxycarbonylphenyl 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-methacryloxypropyl trimethoxysilane, acrylamide, butyl acrylamide, N-dimethylacrylamide, piperidinyl acrylamide, methacrylamide, 4-carboxyphenyl methacrylamide, 4-methoxycarboxyphenyl methacrylamide, methyl chloroacrylate, ethyl-alpha-chloroacrylate, propyl-alpha-chloroacrylate, isopropyl-alpha-chloroacrylate, methyl-alpha-fluoroacrylate, butyl-alpha-butoxycarbonyl methacrylate, butyl-alpha-cyanoacrylate, methyl-alpha-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 organosilicon 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 performed by a solution polymerization method using a solvent, a bulk polymerization method, an emulsion polymerization method, or the like, and particularly preferably a solution polymerization method.
(b) Isocyanate(s)
The isocyanate may be various isocyanates commonly used for producing polyurethane, and for example, aliphatic isocyanates, aromatic isocyanates and derivatives thereof may be cited. The isocyanate is preferably an aliphatic isocyanate from the viewpoints of excellent storage stability and easy control of the reaction rate.
Examples of the aromatic isocyanate include: xylylene Diisocyanate (XDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (also referred to as xylylene diisocyanate TDI), 3 '-dimethylbiphenyl-4, 4' -diisocyanate, 3 '-dimethylbiphenyl-4, 4' -diisocyanate, 2, 4-tolylene diisocyanate uretdione (dimer of 2, 4-TDI), xylene 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 '-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 polyisocyanate, a urethane modified product (including urethane prepolymer) modified with a polyol or the like, a dimer formed from uretdione, an isocyanurate modified product, a carbodiimide modified product, a uretonimine modified product, an allophanate (allophanate) modified product, a urea modified product, and a biuret modified product. The polyisocyanate may be used singly or in combination of two or more. 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, urethane type isocyanates, adduct type isocyanates, and the like can be used. In particular, since the reaction rate can be easily adjusted using a blocked isocyanate, it is preferable.
(a) The mixing ratio of the mixture of the polyol (a 1) and the polyisocyanate (a 2) is not particularly limited, but the molar ratio (NCO/OH) of the hydroxyl group (OH) contained in the polyol to the isocyanate group (NCO) contained in the polyisocyanate is usually preferably 0.7 or more and 1.15 or less. From the viewpoint of preventing hydrolysis of polyurethane, the molar ratio (NCO/OH) is more preferably 0.85 or more and 1.10 or less. In practice, an amount of 3 to 4 times the above-mentioned proper molar ratio may be blended in consideration of the operating environment and the operational errors.
In the resin composition for coating layer, an auxiliary agent commonly used in the reaction between the polyol (a), (a 1) and (a 2) and the isocyanate (b), for example, a chain extender, a crosslinking agent, and the like may be used in combination. Examples of the chain extender and the crosslinking agent include glycols, hexanetriol, trimethylol propane, 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, more preferably 1 μm or more and 15 μm or less. By incorporating such a surface roughness material into 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 can 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 the present specification, the surface roughness (Rz) of the coating layer 4 means ten-point average roughness measured by the method specified in JIS-1994. The surface roughness of the coating layer 4 can be easily adjusted by, for example, the type of the surface roughness material to be blended, the blending amount, and the like.
The kind of the surface roughness material to be blended in the coating layer 4 is not particularly limited, and may be appropriately selected and used from existing Filler materials (fillers). For example, silica of small particle diameter, spherical resin particles, metal oxides, etc. can be used.
The content of the surface roughness material in the coating layer resin composition is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, relative to 100 parts by mass of the coating layer resin composition.
(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, conductive metal oxide, and the like is preferable; a conductive agent having an ion-conductive mechanism such as an alkali metal salt and a quaternary ammonium salt; and a conductive agent having conductive composite particles, which is formed by imparting conductive particles such as carbon black particles to the surfaces of silica particles.
Carbon black is particularly preferred as the conductive material. 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. One of these may be used alone, or two or more of them may be used in combination. In order to obtain a desired resistance, two or more kinds of various conductive agents may be used in combination.
The content of the conductive material in the resin composition for 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 still more preferably 2.0 mass% or more and 10 mass% or less, based on the total amount of the resin composition for coating layer. By adjusting the content of the conductive material to the above range, the resistance value of the developing roller 1 is further stabilized, the printing performance is further improved, and in addition, 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, a filler, and the like.
The coating layer 4 is formed by applying a resin composition for coating layer to the elastic layer 3, and polymerizing and curing at least one of (a) a polyol, (a 1) a polyol having a non-reactive silicone group in a side chain, and (a 2) a single-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, for example, ethyl acetate, butyl acetate, or the like.
The coating of the coating layer resin composition is performed by a conventional coating method, for example, a coating method of a coating liquid for coating the coating layer resin composition, a dipping method of dipping the elastic layer 3 or the like in the coating liquid, or a spraying 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, wherein 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 curing method of the coating layer resin composition applied in the above manner may be any method as long as heat or moisture required for curing the coating layer resin composition or the like can be applied, and examples thereof include a method of heating the elastic layer 3 or the like coated with the coating layer resin composition with a heater and a method of leaving the elastic layer 3 or the like coated with the coating layer resin composition at rest under high humidity. When the resin composition for coating layer is cured by heating, the heating temperature is, for example, preferably 100 ℃ to 200 ℃, more preferably 120 ℃ to 160 ℃. The heating time is preferably 10 minutes to 120 minutes, more preferably 30 minutes to 60 minutes. Instead of coating, a conventional molding method such as extrusion molding, compression molding, injection molding, etc. may be used, such as 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 while curing the resin composition, or a method of curing the laminated resin composition for a coating layer after lamination.
(other constitution)
The developing roller 1 of the present invention may be provided with an intermediate layer such as an adhesive layer or a primer layer between the shaft body 2 and the elastic layer 3 and between the elastic layer 3 and the coating layer 4. Here, among these intermediate layers, particularly the adhesive layer and the primer layer provided between the elastic layer 3 and the coating layer 4, by adjusting the electrical characteristics thereof, the electrical characteristics as the developing roller 1 can be adjusted, whereby 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 a developing roller can be used, and for example, by forming a primer layer made of a polyurethane 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 having the developing roller 1 of the present invention will be described with reference to fig. 2.
The image forming apparatus 10 is a tandem color image forming apparatus in which a plurality of image carriers 11B, 11C, 11M, and 11Y equipped with developing units B, C, M and Y of respective colors are arranged in tandem on a transfer conveyor belt 6, and the developing units B, C, M and Y are arranged in tandem on the transfer conveyor belt 6. The developing unit B includes: the image carrier 11B, for example, a photoconductor (also referred to as a photoconductor 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 interfaces with the image carrier 11B via the transfer 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 this 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 accommodates a one-component non-magnetic 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 adjusting mechanism 24B, such as a doctor blade, which adjusts 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 in pressure contact with the outer peripheral surface of the developer carrier 23B. That is, the developing device 20B is a so-called "contact type developing device". The developing units C, M and Y are configured 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 a description thereof will be omitted.
In the image forming apparatus 10, the developer carrier 23B of the developing device 20B is disposed so that its surface is in contact with or in pressure contact with the surface of the image carrier 11B. The developer carriers 23C, 23M, and 23Y of the developing devices 20C, 20M, and 20Y are disposed so that their surfaces are in contact with or in pressure contact with the surfaces of the image carriers 11C, 11M, and 11Y, as in the developing device 20B. That is, the image forming apparatus 10 is a "contact image forming apparatus".
The fixing mechanism 30 is disposed on the downstream side of the developing unit Y. The fixing mechanism 30 is a pressure heat fixing device including a fixing roller 31, an endless belt support 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 support roller 33, and a pressure roller 32 disposed opposite to the fixing roller 31 in a casing 34 having an opening 35 through which the recording medium 16 passes, and is rotatably supported so 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 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 triboelectrically charged, or may be nonmagnetic developers or magnetic developers. The developing units B, C, M and Y each contain a single-component non-magnetic black developer 22B, a single-component cyan developer 22C, a single-component magenta developer 22M, and a single-component yellow developer 22Y in the casing 21B, 21C, 21M, and 21Y.
The image forming apparatus 10 forms a color image on the recording body 16 as follows. First, in the developing unit B, an electrostatic latent image is formed on the surface of the image carrier 11B charged by the charging mechanism 12B by the exposure mechanism 13B, and a black electrostatic latent image 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, the cyan image, the magenta image, and the yellow image are superimposed on the recording body 16 whose electrostatic latent image is developed into a black image by the developing units C, M and Y, respectively, so that a color image is developed. Next, the recording medium 16 on which the color image is visualized 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, is excellent in developer conveying performance, can suppress occurrence of toner filming, and contributes to formation of high-density and high-quality images over a long period of time. In addition, the image forming apparatus 10 can form high-density and high-quality images for a long period of time.
The developing device and the image forming apparatus of the present invention are not limited to the above examples, and various modifications can 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 image forming apparatus, and may be an electrostatic image forming apparatus, for example. The image forming apparatus provided with the developing roller of the present invention is not limited to a tandem color image forming apparatus in which a plurality of image carriers each having a developing unit are disposed in tandem on a transfer belt, and may be, for example, a monochrome image forming apparatus provided with a single developing unit, a four-cycle color image forming apparatus in which developer images carried on the image carriers are sequentially primary-transferred onto an endless belt, or the like. In addition, although the developer used in the image forming apparatus is a single-component non-magnetic developer, in the present invention, it may be a single-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 in pressure contact 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 is not in contact with the surface of the image carrier.
While the present invention has been described above with reference to the embodiments, 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. Further, as is clear from the description in the claims, the invention having the above-described modifications or improvements may be included in the technical scope of the invention.
Examples
The present invention will be described in detail with reference to examples. Furthermore, the present invention is not limited to the embodiments shown below.
Example 1
(formation of primer layer)
The shaft body (SUM 22, diameter 10mm, length 275 mm) subjected to the electroless nickel plating treatment was cleaned with ethanol, and a silicone PRIMER (trade name "PRIMER No.16", manufactured by Xinyue chemical Co., ltd.) was coated on the surface thereof. The shaft body treated with the primer was baked at 150 ℃ for 10 minutes using a Ji Ershi oven, and then cooled at normal temperature for 30 minutes or more, forming a primer layer on the outer peripheral surface of the shaft body.
(formation of elastic layer)
Next, a silicone rubber composition for forming an elastic layer was prepared as follows. That is, 100 parts by mass of dimethylpolysiloxane (polymerization degree 300) having both ends blocked with dimethylvinylsiloxane groups, 1 part by mass of BET specific surface area of 110m 2 Per gram of the hydrophobized fumed silica (trade name "R-972", manufactured by NIPPON AEROSIL Co., ltd.) 40 parts by mass of a silica having an average particle diameter of 6 μm and a bulk density of 0.25g/cm 3 Diatomite (trade name "Oplite W-3005S", manufactured by Chuo Silika Co., ltd.) and 5 parts by mass of acetylene BLACK (trade name "DENKA BLACK HS-100", manufactured by Denka Co., ltd.) were added to a planetary mixer, stirred for 30 minutes, and then passed through a three-roll mill once. This was returned to the planetary mixer again, and 2.1 parts by mass of methyl hydrogenised polysiloxane having Si-H groups at both ends and side chains (polymerization degree 17, si-H amount 0.0060 mol/g), 0.1 part by mass of ethynyl cyclohexanol, 0.1 part by massThe addition-curable liquid conductive silicone rubber composition was prepared by stirring, deaerating and kneading the mixture for 30 minutes with a platinum catalyst (Pt concentration: 1 mass%).
The prepared addition-curable liquid conductive silicone rubber composition was molded by injection molding using a mold, and an elastomer made of a rubber material was molded on the outer peripheral surface of the shaft body. In injection molding, the addition-curable liquid conductive silicone rubber composition was cured by heating at 120℃for 10 minutes, and was 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 (manufactured by Tosoh Co., ltd., trade name "Nipporan 981") of 95.4 parts by mass
(a1) 4.6 parts by mass of a silicone grafted acrylic polyol
(b) Urea acid ester isocyanate (trade name "TPA-B80E" manufactured by Asahi Kabushiki Kaisha Co., ltd.) was 49.6 parts by mass
(c) A surface roughness material (AEROSIL (registered trademark) R711 manufactured by japan AEROSIL co., ltd.) was 13.5 parts by mass
(d) 3 parts by mass of an electroconductive material (MA 600, manufactured by Mitsubishi chemical controlled group)
(a 1) Synthesis of Silicone grafted acrylic polyol
The silicone-grafted acrylic polyol of (a 1) is prepared by radical polymerization of the compounds represented by the above general formulae (1) and (2) in the presence of Azobisisobutyronitrile (AIBN).
The coating layer was coated on the outer peripheral surface of the elastic layer with the resin composition by spraying, and heated at 160℃for 30 minutes, thereby forming a coating layer having a layer thickness of 20. Mu.m. In this way, a developing roller having a shaft body, an elastic layer, and a coating layer is manufactured.
Examples 2 to 7 and comparative examples 1 to 3
Using the materials and the proportions shown in table 1, a developing roller was manufactured in the same manner as in example 1.
In Table 1, (a) PolyCASTOR #10 manufactured by Eyew oil Co., ltd., and (a 2) one-terminal diol type silicone oil X-22-176DX manufactured by Xinyue chemical Co., ltd., and adduct type isocyanate E402-B80B manufactured by Xuehua chemical Co., ltd., were used.
[ evaluation ]
An image forming apparatus HL-3170CDW (model, manufactured by Brother Industries, ltd.) was prepared, and the developing rollers of the image forming apparatus were replaced with the developing rollers of the respective examples and comparative examples to obtain an image forming apparatus. The obtained image forming apparatus was evaluated for dynamic friction coefficient, static friction coefficient and belt by the following methods.
(coefficient of dynamic friction and coefficient of static friction)
The produced developing roller was measured several times in the longitudinal direction of the roller under a load of 300N according to the measurement method using i-tester TL701 (R contactor) manufactured by Trinity Lab Co., ltd. To obtain the arithmetic average value as the static friction coefficient and dynamic friction coefficient of each test piece.
(evaluation of banding)
Each manufactured conductive roller was mounted as a developing roller on a contact-type image forming apparatus HL-3170CDW (model number, 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 same level of banding as in the conventional product was evaluated as "C", and the case where sufficient improvement in banding was observed was evaluated as "a".
In the image area described above, the high-density portion extending in the short side direction of the A4 paper is a stripe. In the evaluation of the belt, as the developer and the developer amount adjusting mechanism, the developer and the developer amount adjusting mechanism mounted on the image forming apparatus are used.
The evaluation results are shown in table 1.
TABLE 1
As shown in table 1, in the examples containing (a 1) a polyol having a non-reactive silicone group in a side chain or (a 2) a single-terminal diol type silicone oil as a raw material of the resin composition for a coating layer, both the dynamic friction coefficient and the static friction coefficient were lower than those of the comparative examples, and therefore it was found that the band was improved.
This is considered to be because the silicone chain in (a 1) is a non-reactive group, and (a 2) is a single-terminal silicone chain, and the silicone chain is not incorporated into polyurethane as a main chain but is present as a side chain having a relatively high degree of freedom on the surface of the coating layer, so that the coefficient of friction can be reduced.

Claims (6)

1. A developing roller is provided with:
an elastic layer formed on the 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 a polycarbonate diol, and at least one of (a 1) a silicone grafted acrylic polyol and (a 2) a single-terminal diol type silicone oil,
the surface roughness material (c) is a small particle size silica having an average particle size of 1 μm or more and 15 μm or less,
the content of the (c) surface roughness material is 1 to 40 parts by mass with respect to 100 parts by mass of the resin composition for coating layer.
2. The developing roller according to claim 1, wherein
The content of at least one of the (a 1) silicone grafted acrylic polyol and the (a 2) one-terminal diol type silicone oil in the (a) polyol is 2 mass% or more and 60 mass% or less.
3. The developing roller according to claim 1 or 2, wherein,
the silicone-grafted acrylic polyol (a 1) and the single-terminal diol-type silicone oil (a 2) contain only the silicone-grafted acrylic polyol (a 1).
4. The developing roller according to claim 3, wherein,
the content of the (a 1) silicone-grafted acrylic polyol in the (a) polyol is 2 mass% or more and 40 mass% or less.
5. A developing device, wherein,
a developing roller according to any one of claims 1 to 4.
6. An image forming apparatus, wherein,
a developing roller according to any one of claims 1 to 4.
CN201980071075.XA 2018-11-27 2019-11-11 Developing roller, developing device, and image forming apparatus Active CN112955824B (en)

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PCT/JP2019/044136 WO2020110686A1 (en) 2018-11-27 2019-11-11 Developing roller, developing device, and image formation device

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WO2020110686A1 (en) 2020-06-04
JP2020086171A (en) 2020-06-04

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