JP6603642B2 - Developing roller and image forming apparatus - Google Patents

Description

  The present invention relates to a developing roller and an image forming apparatus including the developing roller.

  2. Description of the Related Art Conventionally, various image forming apparatuses using, for example, an electrophotographic system have been adopted in printers, copiers, facsimiles, and multi-function machines thereof. An image forming apparatus using an electrophotographic system includes a developing roller for carrying a developer (toner) and supplying the developer to an image carrier.

  As such a developing roller, a roller including a shaft, an elastic layer provided on the outer peripheral surface of the shaft, and a coating layer provided on the elastic layer is known. For example, Patent Document 1 proposes a developing roller using a resin material containing a urethane resin and a polysiloxane component in a coating layer.

JP 2003-167398 A

  In the image forming apparatus, when the developing roller deteriorates, the developer (toner) carried on the developing roller may leak or the printing performance may deteriorate. For this reason, the developing roller is required to have high durability, which is unlikely to deteriorate due to wear, breakage, or the like during long-term use.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing roller having high durability in which wear, breakage, and the like during long-term use are suppressed. Another object of the present invention is to provide an image forming apparatus having the above-described developing roller, in which leakage of developer and deterioration in printing performance are sufficiently suppressed, and excellent in long-term reliability.

  One aspect of the present invention relates to a developing roller including a shaft body and a roller body provided on the outer peripheral surface of the shaft body. In this developing roller, the roller body includes a cylindrical elastic layer, a coat layer that covers the outer peripheral surface of the elastic layer, and end protection layers that are provided on both ends of the roller body in the axial direction. The elastic layer contains silicone rubber and metal silicon particles, the coat layer contains a urethane resin, and the end protective layer contains a fluorine-containing resin.

  In one embodiment, the thermal conductivity of the elastic layer may be 0.2 to 0.7 W / mK.

  In one embodiment, the resin material constituting the coat layer may have an elongation of 350% or more.

  In one embodiment, the urethane resin may be a copolymer of a polyol component and a polyisocyanate component, and the number average molecular weight of the polyol component may be 800-15000.

  In one aspect, the fluororesin may have at least one structural unit selected from the group consisting of ethylene tetrafluoride units and ethylene trifluoride units.

  Another aspect of the present invention relates to an image forming apparatus including the developing roller.

  According to the present invention, it is possible to provide a developing roller having high durability in which wear, breakage, and the like during long-term use are suppressed. In addition, according to the present invention, an image forming apparatus that includes the developing roller and sufficiently suppresses leakage of developer and deterioration in printing performance and is excellent in long-term reliability is provided.

It is a front view which shows the outline of the developing roller which concerns on one Embodiment. It is sectional drawing which shows the cross section of the developing roller along the II-II line of FIG. It is sectional drawing which shows the cross section of the developing roller along the III-III line | wire of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the drawings are partially exaggerated for easy understanding, and dimensional ratios and the like are not limited to those described in the drawings.

  FIG. 1 is a front view showing an outline of the developing roller according to the present embodiment, FIG. 2 is a sectional view showing a section of the developing roller along the line II-II in FIG. 1, and FIG. FIG. 3 is a cross-sectional view showing a cross section of the developing roller along line III-III in FIG.

  The developing roller 1 according to the present embodiment includes a shaft body 10 and a roller body 20 provided on the outer peripheral surface of the shaft body 10. The roller body 20 includes a cylindrical elastic layer 21, a coat layer 23 that covers the outer peripheral surface of the elastic layer 21, and end protection layers 25 provided on both ends of the roller body 20 in the axial direction.

(Shaft 10)
The shaft body 10 may be a shaft body used for a known developing roller. The shaft body 10 may be made of, for example, a metal such as iron, aluminum, stainless steel, or brass, and such a shaft body 10 can be rephrased as a “core metal”. The shaft body 10 may have conductivity.

  The shaft body 10 is not necessarily made of metal, and may be made of, for example, a resin material. The resin material may be, for example, a conductive resin in which a conductivity imparting agent is blended with a thermoplastic resin or a thermosetting resin.

  The shaft body 10 may be made of one material, and may be made of two or more materials. The shaft body 10 may be composed of, for example, a core material and an outer layer that covers the outer peripheral surface of the core material. Specifically, the shaft body 10 may be obtained by, for example, plating a metal core material. Further, the shaft body 10 may be a conductive material obtained by performing plating on an insulating core made of a resin material, for example.

  In the present embodiment, the shaft body 10 has a cylindrical shape, but the shape of the shaft body 10 is not limited to this. The shaft body 10 may be, for example, a columnar shape, a cylindrical shape, a polygonal column shape, a polygonal cylindrical shape, or the like.

  The outer peripheral surface of the shaft body 10 may be subjected to a treatment such as a cleaning treatment, a degreasing treatment, and a primer treatment in order to improve the adhesion with the elastic layer 21.

  The length of the shaft body 10 in the axial direction is not particularly limited, and may be appropriately adjusted according to the form of the installed image forming apparatus. For example, in one aspect, the axial length of the shaft body 10 may be 260 to 290 mm, preferably 270 to 280 mm.

  The outer diameter of the shaft body 10 is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed. For example, in one aspect, the outer diameter (diameter of the circumscribed circle) of the shaft body 10 may be 6 to 10 mm, and preferably 7 to 8 mm.

(Elastic layer 21)
The elastic layer 21 is provided on the outer peripheral surface of the body portion of the shaft body 10 and contains silicone rubber and metal silicon particles. In the present embodiment, since the elastic layer 21 contains metal silicon particles, the thermal conductivity of the elastic layer 21 is improved and the developer on the developing roller 1 is prevented from melting due to frictional heat or the like.

  The silicone rubber may be at least one selected from the group consisting of silicone rubber and silicone-modified rubber. Silicone rubber can also be referred to as a crosslinked product of silicone raw rubber. The silicone raw rubber is not particularly limited, and may be a known silicone raw rubber. Examples of the silicone raw rubber include a vinyl group-containing silicone raw rubber (more specifically, for example, a vinyl group-containing dimethyl silicone raw rubber, a vinyl group-containing phenyl silicone raw rubber, a vinyl group-containing fluorosilicone raw rubber, etc.) or a modified product thereof. It is done.

  In the present specification, metallic silicon refers to silicon having a β-tin structure. The metallic silicon particles are particles composed of metallic silicon, and may optionally contain non-metallic silicon having a diamond structure. Moreover, the metal silicon particles may contain impurities such as Fe, Ni, Al, and oxides thereof.

  From the viewpoint of excellent thermal conductivity, the purity of the metal silicon particles is preferably 50% or more (50 to 100%), and preferably 80% or more (80 to 100%). More preferably, it is 95% or more (95 to 100%).

  The average primary particle diameter of the metal silicon particles is preferably 100 μm or less, more preferably 50 μm or less, further preferably 25 μm or less, and may be 20 μm or less. With such an average primary particle size, the unevenness of the outer peripheral surface of the elastic layer 21 is reduced, and the outer peripheral surface of the developing roller 1 becomes more uniform. The average primary particle size of the metal silicon particles is preferably 0.1 μm or more, more preferably 0.5 μm or more, and further preferably 1 μm or more. The metal silicon particles having such an average primary particle diameter are easy to produce and are excellent in dispersibility in the elastic layer 21.

  The metal silicon particles may be surface-treated for the purpose of improving the compounding property with the silicone rubber. For the surface treatment, a known surface treatment agent such as a coupling agent may be used. The surface treatment may be, for example, a hydrophobization treatment that hydrophobizes the surface of the metal silicon particles.

  Examples of the surface treatment agent for surface treating the metal silicon particles include silicone oil (eg, linear or cyclic dimethylpolysiloxane), silane compounds (organochlorosilanes, organohydroxysilanes, organoalkoxysilanes). Etc.), silane coupling agents (organoalkoxysilanes containing organic functional groups, etc.), titanate coupling agents, hydrocarbon oils, waxes and the like. Further, as the surface treatment agent, a silane compound having at least one hydrolyzable group (for example, organohydroxysilane such as trimethylsilanol; organochlorosilane such as alkylchlorosilane, alkenylchlorosilane, arylchlorosilane; alkylalkoxysilane, alkenylalkoxysilane) , Organoalkoxysilanes such as arylalkoxysilanes) or partial hydrolysates thereof, silane coupling agents or partial hydrolysates thereof, organic silazanes (for example, hexamethyldisilazane, 1,3-divinyl-1,1,3 , 3-tetramethyldisilazane and the like) and organopolysiloxanes having hydrolyzable groups are preferably used. As the organic functional group in the above-mentioned silane coupling agent, for example, an alkenyl group such as a vinyl group or an allyl group, or a functional group such as an amino group, an epoxy group, a methacryloxy group, an acryloxy group or a mercapto group An alkyl group etc. are mentioned.

  The metal silicon particles may be dispersed in the elastic layer 21. The content of the metal silicon particles is preferably 5 parts by mass or more and more preferably 10 parts by mass or more with respect to 100 parts by mass of the silicone rubber. By increasing the content of the metal silicon particles, the thermal conductivity of the elastic layer 21 is more significantly improved, and the melting of the developer on the developing roller 1 due to frictional heat or the like is more significantly prevented. The content of the metal silicon particles may be 50 parts by mass or less, preferably 45 parts by mass or less, with respect to 100 parts by mass of the silicone rubber. By reducing the content of the metal silicon particles, the mechanical strength of the elastic layer 21 is improved, and deterioration due to scraping during operation is remarkably suppressed.

  The elastic layer 21 may further contain a conductivity imparting agent. The conductivity imparting agent is not particularly limited as long as it is a component that can impart conductivity to the elastic layer 21. Examples of the conductivity imparting agent include conductive powder and ionic conductive material. Examples of the conductive powder include conductive carbon (eg, ketjen black, acetylene black, etc.), rubber carbons (eg, SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT, etc.), metal or Examples thereof include metal oxide powders (for example, titanium oxide, zinc oxide, nickel, copper, silver, germanium, etc.) and conductive polymer powders (for example, polyaniline, polypyrrole, polyacetylene, etc.). Examples of the ion conductive substance include inorganic ionic conductive substances such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride.

  When the elastic layer 21 contains a conductivity imparting agent, the content of the conductivity imparting agent may be, for example, 2 to 80 parts by mass, or 5 to 60 parts by mass with respect to 100 parts by mass of the silicone rubber. It is preferably 8 to 40 parts by mass.

  The elastic layer 21 may further contain additives other than those described above. Specific examples of the additive include dispersants such as low-molecular siloxane esters, silanols, and phenylsilanediols. Specific examples of the additive include heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. Moreover, as an additive, you may use various carbon functional silane, various olefin type elastomers, etc. for improving adhesiveness, moldability, etc. Moreover, as an additive, you may use the halogen compound etc. which give a flame retardance.

  The elastic layer 21 may be formed using, for example, an addition curable type millable silicone rubber composition or an addition curable type liquid silicone rubber composition. That is, the elastic layer 21 may be composed of a cured product of an addition-curable millable silicone rubber composition, or may be composed of a cured product of an addition-curable liquid silicone rubber composition.

The addition-curable millable conductive silicone rubber composition includes, for example, (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, (C) a conductive material, and (X) metal silicon. It may contain particles.
R ¹ _n SiO _{(4-n) / 2} (1)
In formula (1), n represents a positive number of 1.95 to 2.05. 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 1-12, more preferably 1-8.

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

  (A) Organopolysiloxane has molecular chain terminals such as trialkylsilyl group such as trimethylsilyl group, dialkylaralkylsilyl group such as dimethylvinylsilyl group, dialkylhydroxysilyl group such as dimethylhydroxysilyl group, trivinylsilyl group, etc. It is preferably blocked with a triaralkylsilyl group or the like.

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

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

  (A) The organopolysiloxane preferably has a viscosity at 25 ° C. of 100 cSt or more, more preferably 100,000 to 10,000,000 cSt. The degree of polymerization of (A) organopolysiloxane may be, for example, 100 or more, preferably 3000 or more, may be 100,000, and preferably 10,000 or less.

  (B) As a filler, a silica type filler is mentioned, for example. Examples of the silica filler include fumed silica and precipitated silica.

As the silica-based filler, a surface-treated silica-based filler that has been surface-treated with a silane coupling agent represented by R ² Si (OR ³ ) ₃ can be suitably used. Here, R ² may be a group having a vinyl group or an amino group, and may be, for example, a glycidyl group, a vinyl group, an aminopropyl group, a methacryloxy group, an N-phenylaminopropyl group, a mercapto group, or the like. R ³ may be an alkyl group, for example, a methyl group, an ethyl group, or the like. A silane coupling agent can be easily obtained as, for example, trade names “KBM1003”, “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. The surface-treated silica-based filler can be obtained by treating the surface of the silica-based filler with a silane coupling agent according to a conventional method. A commercially available product may be used as the surface-treated silica-based filler. M.M. A trade name “Zeothix 95” manufactured by HUBER Co., Ltd. may be mentioned.

  The compounding amount of the silica filler is preferably 11 to 39 parts by mass and more preferably 15 to 35 parts by mass with respect to 100 parts by mass of (A) the organopolysiloxane. Moreover, it is preferable that the average particle diameter of a silica type filler is 1-80 micrometers, and it is more preferable that it is 2-40 micrometers. In addition, the average particle diameter of a silica type filler can be measured as a median diameter using the particle size distribution measuring apparatus by a laser beam diffraction method.

  (C) The electroconductive material should just be what can provide electroconductivity to the elastic layer 3, and may be the electroconductivity imparting agent mentioned above. (C) Carbon black is preferred as the conductive material. (C) Two or more conductive materials may be used in combination. (C) The compounding quantity of an electroconductive material may be 2-80 mass parts with respect to 100 mass parts of (A) organopolysiloxane, for example.

  (X) The metal silicon particles are as described above. (X) The compounding amount of the metal silicon particles is preferably 5 parts by mass or more and more preferably 10 parts by mass or more with respect to 100 parts by mass of (A) organopolysiloxane. Moreover, it is preferable that it is 50 mass parts or less with respect to 100 mass parts of (A) organopolysiloxane, and, as for content of a metal silicon particle, it is more preferable that it is 45 mass parts or less.

  The addition-curable millable conductive silicone rubber composition may further contain additives other than (A) to (C) and (X). Examples of additives include auxiliary agents (chain extenders, crosslinking agents, etc.), catalysts, dispersants, foaming agents, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, An emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, a solvent and the like can be mentioned.

  Specific examples of additives include (A) dimethylsiloxane oil having a lower degree of polymerization than organopolysiloxane, polyether-modified silicone oil, silanol, diphenylsilanediol, and α, ω-dimethylsiloxanediol, etc. Dispersants such as low molecular siloxanes and silanes can be mentioned. Specific examples of the additive include heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. Moreover, as an additive, you may use various carbon functional silane, various olefin type elastomers, etc. for improving adhesiveness, moldability, etc.

  The addition curable liquid conductive silicone rubber composition includes, for example, (D) an organopolysiloxane having two or more alkenyl groups in the molecule, and (E) two or more hydrogen atoms bonded to silicon atoms in the molecule. It may contain an organohydrogenpolysiloxane, (F) a filler, (G) a conductivity-imparting agent, (H) an addition reaction catalyst, and (Y) metal silicon particles.

(D) As the organopolysiloxane, a compound represented by the following average composition formula (2) is preferable.
R ⁴ _a SiO _{(4-a) / 2} (2)
In formula (2), a represents a positive number of 1.5 to 2.8, preferably 1.8 to 2.5, and more preferably 1.95 to 2.05. R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. However, at least two of R ^{4 in} one molecule are alkenyl groups. The number of carbon atoms of the hydrocarbon group is preferably 1-12, more preferably 1-8.

Examples of R ⁴ include the same groups as those exemplified as R ¹ above. Moreover, it is preferable that at least two of R ^{4 in} one molecule are alkenyl groups, and other R ⁴ is an alkyl group. The alkenyl group is preferably a vinyl group, and the alkyl group is preferably a methyl group. Also, for example, 90% or more of R ⁴ may be an alkyl group (preferably a methyl group). (D) The content of the alkenyl groups in the organopolysiloxane may be, for example, ^{1.0 × 10 -6 ~5.0 × 10 -3} mol / g, 5.0 × 10 -6 ~1.0 It is preferable that it is * 10 < ^-3 > mol / g.

  (D) The organopolysiloxane is preferably liquid at 25 ° C., and preferably has a viscosity at 25 ° C. of 100 to 1,000,000 mPa · s (more preferably 200 to 100,000 mPa · s). The average degree of polymerization of the (D) organopolysiloxane is preferably 100 to 800, more preferably 150 to 600.

(E) As the organohydrogenpolysiloxane, a compound represented by the following average composition formula (3) is preferable.
R ⁵ _b H _c SiO _{(4-b-c) / 2} (3)
In 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. 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 1-10. Examples of R ⁵ include the same groups as those exemplified as R ¹ above.

  (E) Organohydrogenpolysiloxane has two or more hydrogen atoms (Si-H) bonded to silicon atoms in one molecule, and preferably has three or more. Further, (E) the number of hydrogen atoms bonded to silicon atoms in the organohydrogenpolysiloxane in one molecule may be 200 or less, or 100 or less.

  (E) In the organohydrogenpolysiloxane, the content of hydrogen atoms bonded to silicon atoms is preferably 0.001 to 0.017 mol / g, and preferably 0.002 to 0.015 mol / g. More preferred.

(E) Examples of organohydrogenpolysiloxane include, for example, trimethylsiloxy group-capped methylhydrogen polysiloxane at both ends, trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, and both ends dimethylhydrogensiloxy group-capped Dimethylpolysiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane diphenylsiloxane-dimethylsiloxane _{copolymer, (CH} 3) 2 _HSiO consisting _1/2 units and _{SiO 4/2} units, and copolymers thereof, and, CH _{3) 2} HSiO _1/2 units and _{SiO 4/2} units and _{(C 6} H ₅₎ copolymers composed of _{SiO 3/2} units and the like.

  (E) The compounding amount of the organohydrogenpolysiloxane is preferably 0.1 to 30 parts by mass and more preferably 0.3 to 20 parts by mass with respect to 100 parts by mass of the (D) organopolysiloxane. preferable. The molar ratio of Si-H of (E) organohydrogenpolysiloxane to the alkenyl group of (D) organopolysiloxane is preferably 0.3 to 5.0, preferably 0.5 to 2.5. It is more preferable that

  (F) The filler may be, for example, an inorganic filler. By blending the filler (F) with the addition curable liquid conductive silicone rubber composition, the compression set is reduced, the volume resistivity is stable over time, and sufficient roller durability is obtained.

  (F) The average particle diameter of the filler is preferably 1 to 30 μm, more preferably 2 to 20 μm. (F) When the average particle diameter of a filler is 1 micrometer or more, there exists a tendency for the time-dependent change of volume resistivity to be suppressed further. Further, when the average particle size of the filler (F) is 30 μm or less, the elastic layer 3 having further excellent durability tends to be obtained. In addition, the average particle diameter of (F) filler can be measured as a median diameter using the particle size distribution measuring apparatus by a laser beam diffraction method.

(F) The bulk density of the filler is preferably 0.1 to 0.5 g / cm ³ , more preferably 0.15 to 0.45 g / cm ³ . (F) When the bulk density of the filler is 0.1 g / cm ³ or more, the compression set can be further lowered, and the change in volume resistivity with time tends to be further suppressed. In addition, when the bulk density of the filler (F) is 0.5 g / cm ³ or less, the elastic layer 3 having further excellent durability tends to be obtained. In addition, the bulk density of (F) filler can be calculated | required based on the measuring method of apparent specific gravity of JISK6223.

  Examples of the filler (F) include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and a hollow filler. Among these, as the filler (F), a pulverized product of diatomaceous earth, pearlite, and foamed pearlite can be suitably used.

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

  (G) The conductivity imparting agent is not particularly limited as long as it can impart conductivity to the elastic layer 3. (G) The conductivity imparting agent may be, for example, the conductivity imparting agent described above. (G) As the conductivity imparting agent, for example, conductive carbon, carbon for rubber, metal, metal oxide, conductive powder such as conductive polymer, ionic conductive agent, and the like are preferably used.

  (G) It is preferable that the compounding quantity of an electroconductivity imparting agent is 1-100 mass parts with respect to 100 mass parts of (D) organopolysiloxane, and it is more preferable that it is 2-80 mass parts.

  (H) The addition reaction catalyst may be any catalyst that can activate the addition reaction between (D) organopolysiloxane and (E) organohydrogenpolysiloxane. (H) As an addition reaction catalyst, the catalyst which has a platinum group element is mentioned, for example. Examples of the catalyst having a platinum group element include platinum-based catalysts (for example, platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, and a complex of chloroplatinic acid and olefins. Platinum bisacetoacetate), palladium-based catalysts, rhodium-based catalysts, and the like.

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

  (Y) The metal silicon particles are as described above. The compounding amount of the (Y) metal silicon particles is preferably 5 parts by mass or more with respect to a total of 100 parts by mass of the (D) organopolysiloxane and the (E) organohydrogenpolysiloxane, and is 10 parts by mass or more. More preferably. The content of the metal silicon particles is preferably 50 parts by mass or less, and 45 parts by mass or less, with respect to 100 parts by mass in total of (D) organopolysiloxane and (E) organohydrogenpolysiloxane. It is more preferable.

  The addition-curable liquid conductive silicone rubber composition may further contain additives other than (D) to (H) and (Y). Examples of additives include auxiliary agents (chain extenders, crosslinking agents, etc.), foaming agents, dispersants, anti-aging agents, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, Examples include a heat resistance improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a mold release agent, a diluent, a reactive diluent, a solvent, and the like.

  Specific examples of the additive include dispersants such as low molecular siloxane ester, polyether-modified silicone oil, silanol, and phenylsilanediol. Specific examples of the additive include heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. Moreover, as an additive, you may use various carbon functional silane, various olefin type elastomers, etc. for improving adhesiveness, moldability, etc. Moreover, as an additive, you may use the halogen compound etc. which give a flame retardance.

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

  The thermal conductivity of the elastic layer 21 is preferably 0.2 to 0.7 W / mK, and more preferably 0.3 to 0.6 W / mK. With such thermal conductivity, melting of the developer on the developing roller 1 due to frictional heat or the like is more significantly prevented. In the present specification, the thermal conductivity of the elastic layer 21 indicates a value measured by a box-type probe method using a rapid thermal conductivity meter (trade name “QTM-500”, manufactured by Kyoto Electronics Industry Co., Ltd.). .

  The compression set of the elastic layer 21 is preferably 2 to 15%, and more preferably 3 to 10%. Thereby, the distortion of the outer peripheral surface of the developing roller 1 due to the deformation of the elastic layer 21 is sufficiently suppressed, and the uniform image forming ability is maintained for a longer period. In the present specification, the compression set indicates a value measured according to JIS K6262 “How to obtain compression set at normal temperature, high temperature and low temperature of vulcanized rubber and thermoplastic rubber”.

  The thickness of the elastic layer 21 is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed. For example, in one embodiment, the elastic layer 21 may have a thickness of 2 to 8 mm, preferably 5 to 7 mm. In the present specification, the thickness of the elastic layer 21 indicates a thickness in a direction perpendicular to the axial direction of the developing roller 1.

  The outer diameter of the elastic layer 21 is not particularly limited, and may be appropriately adjusted according to the form of the image forming apparatus to be installed. For example, in one aspect, the outer diameter of the elastic layer 21 may be 12 to 22 mm, preferably 13 to 21 mm. Note that the outer diameter of the elastic layer 21 in this specification indicates the outer diameter in a cross section perpendicular to the axial direction of the developing roller 1.

  The outer peripheral surface of the elastic layer 21 is subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, excimer treatment, UV treatment, itro treatment, frame treatment, etc. for the purpose of improving the adhesion with the coating layer 23. It's okay.

(Coat layer 23)
The coat layer 23 covers the outer peripheral surface of the elastic layer 21 and is a layer containing a urethane resin. In the present embodiment, the coat layer 23 constitutes a carrying surface that carries the developer. The coat layer 23 is interposed between the elastic layer 21 and the end protective layer 25, and also serves as a cushion that alleviates an impact when another member contacts the end protective layer 25.

  The resin material constituting the coat layer 23 contains a urethane resin. The urethane resin may be a polymer of a polyol component and a polyisocyanate component.

  The polyol component is a compound having two or more hydroxyl groups. Examples of the polyol component include polyester polyol, polycarbonate polyol, polyether polyol, polycaprolactone polyol, and polyacryl polyol. The polyol component may be one of these or two or more.

  The polyester polyol may have two or more ester bonds and two or more hydroxyl groups in the molecule. The polyester polyol may be, for example, a condensation reaction product of a dicarboxylic acid and a polyol. Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid. Examples of the polyol include diols such as hexanediol and butanediol, and triols such as 2,4-butanetriol.

  The polycarbonate polyol may have two or more carbonate bonds and two or more hydroxyl groups in the molecule. Examples of the polycarbonate polyol include a condensation reaction product of the above-described diol and a carbonate compound. Examples of the carbonate compound include dialkyl carbonate, diaryl carbonate, and alkylene carbonate.

  The polyether polyol may have two or more ether bonds and two or more hydroxyl groups in the molecule. Examples of the polyether polyol include a polymer obtained by addition polymerization of polyethylene oxide or propylene oxide to a polyhydric alcohol. The polycaprolactone polyol may have a polycaprolactone skeleton and two or more hydroxyl groups.

  The polyacryl polyol may have a repeating unit derived from an acrylic monomer and two or more hydroxyl groups. The acrylic monomer may be (meth) acrylic acid, (meth) acrylic acid ester, acrylamide or the like.

  The number average molecular weight of the polyol component is preferably 800 to 15000 and more preferably 1000 to 5000 from the viewpoint of improving the flexibility of the coat layer 23. In addition, in this specification, a number average molecular weight shows the value of standard polystyrene conversion by a gel permeation chromatography (GPC).

  The polyisocyanate component is a compound having two or more isocyanate groups (—NCO). Examples of the polyisocyanate component include aliphatic diisocyanates such as hexamethylene diisocyanate, aromatic diisocyanates such as diphenylmethane diisocyanate and tolylene diisocyanate, and other polyisocyanates.

  The resin material constituting the coat layer 23 may be a cured product of a resin raw material including a polyol component and a polyisocyanate component. The resin raw material may further contain other components other than the polyol component and the polyisocyanate component. As other components, for example, auxiliary agents (for example, chain extenders, crosslinking agents, etc.) usually used in the reaction of a polyol component and a polyisocyanate component, a catalyst, a dispersing agent, a conductivity imparting agent, a roughness imparting material. Etc. Examples of the auxiliary agent include glycols, hexanetriol, trimethylolpropane, and amines. Moreover, as a conductivity imparting agent, the same thing as the conductivity imparting agent which can be mix | blended with the elastic layer 21 can be illustrated.

The resin material constituting the coat layer 23 preferably has an elongation of 350% or more. Thereby, the durability and cushioning properties of the coat layer 23 are improved, and the long-term reliability of the developing roller 1 tends to be further improved. The elongation percentage of the resin material is more preferably 400% or more. The upper limit of the elongation percentage of the resin material is not particularly limited, but may be, for example, 800% or less. In this specification, the elongation percentage of the resin material is determined by conducting a tensile test on a strip-shaped test piece of 70 mm × 15 mm × 0.05 mm, the distance between chucks before measurement (L ₁ ), and the distance between chucks immediately before fracture. distance indicates a value obtained by the following formula from _{(L 2)} (i).
Elongation rate (%) = (L ₂ / L ₁ ) × 100 (i)

  The thickness of the coat layer 23 is not particularly limited, and may be, for example, 13 μm or more, and preferably 17 μm or more. By increasing the thickness of the coat layer 23, deterioration such as wear and breakage is remarkably suppressed, and higher durability tends to be obtained. Moreover, the thickness of the coat layer 23 may be, for example, 100 μm or less, and is preferably 50 μm or less. Thereby, the effect of this invention can fully be acquired, suppressing material usage-amount.

  The outer peripheral surface of the coat layer 23 may be subjected to a surface treatment for the purpose of improving the developer carrying performance.

(End protection layer 25)
The end protective layer 25 is provided on the outer peripheral surface of the coat layer 23 at each of both end sides in the axial direction. The end protection layer 25 is provided at a position where the end protection layer 25 is opposed to the developing roller 1 and is in sliding contact with an adjustment member that adjusts the amount of developer carried, and reduces the heat generated by friction with the preparation member. It plays a role of suppressing the melting of the developing roller 1, suppressing the damage of the developing roller 1 due to the friction with the adjusting member, and improving the long-term reliability of the developing roller 1.

  The adjustment member usually includes a developing blade that is installed in parallel with the outer periphery of the developing roller 1 and a seal portion that contacts the end of the developing roller 1 at both ends of the developing blade and prevents leakage of the developer. . The end protection layer 25 is provided on the contact surface with the seal portion, and when the developing roller 1 rotates at a high speed, the outer peripheral surface of the end protection layer 25 and the seal portion are in sliding contact.

  The end protective layer 25 is made of a resin material containing a fluorine-containing resin. In the end protective layer 25, the fluorine-containing resin is preferably present as a matrix constituting the layer. Thereby, the above-mentioned effect is more remarkably exhibited.

  The fluorine-containing resin may be a polymer having a structural unit containing a fluorine atom. Examples of such a fluorine-containing resin include PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetrafluoroethylene-hexafluoropropylene resin), ECTFE (ethylene-chlorotrifluoroethylene copolymer), Examples include ETFE (ethylene-tetrafluoroethylene copolymer), PCTFE (polychlorotrifluoroethylene), PVDF (polyvinylidene fluoride resin), PVF (polyvinyl fluoride), and the like.

  The fluororesin preferably has at least one structural unit selected from the group consisting of an ethylene tetrafluoride unit and an ethylene trifluoride unit from the viewpoint that the above-described effects can be obtained remarkably.

  The fluorine-containing resin may be a resin obtained by crosslinking a fluorine resin having a crosslinkable group with a crosslinking agent. The combination of a crosslinkable group and a crosslinking agent may be a known combination. For example, when the crosslinkable group is a hydroxyl group, a polyisocyanate component can be suitably used as the crosslinker.

  The fluorine atom content in the fluorine-containing resin is preferably 30 to 60% by mass, more preferably 40 to 50% by mass, based on the total amount of the fluorine-containing resin. Thereby, there exists a tendency for the suitable dynamic friction coefficient mentioned later to become easy to be obtained.

  The resin material constituting the end protective layer 25 may further contain components other than the fluorine-containing resin. Examples of other components include a conductivity imparting agent, a roughness imparting material, and a lubricating oil. The content of these other components may be, for example, 50% by mass or less based on the total amount of the resin material, and is preferably 40% by mass or less.

  The coefficient of dynamic friction on the outer peripheral surface of the end protective layer 25 is preferably 0.30 or less, and more preferably 0.27 or less. As a result, the above-described effects are more remarkably exhibited. In addition, in this specification, a dynamic friction coefficient shows the value measured based on "the plastic-film and sheet-friction coefficient test method" of JISK7125.

  The thickness of the end protection layer 25 may be, for example, 5 μm or less, and is preferably 3 μm or less. Moreover, the thickness of the edge part protective layer 25 may be 0.5 micrometer or more, for example, and it is preferable that it is 1 micrometer or more.

  The width (length along the axial direction) of the end protective layer 25 may be adjusted as appropriate according to the form of the image forming apparatus to be installed. The width of the end protective layer 25 may be, for example, 5 to 15 mm, and preferably 7 to 13 mm.

  The roller body 20 may further include a configuration other than the elastic layer 21, the coat layer 23, and the end protective layer 25. For example, the roller body 20 may further include an adhesive layer for improving the interlayer adhesive strength between the layers.

  The developing roller 1 according to this embodiment can be suitably used as a developer carrier in an image forming apparatus.

  In one aspect of the image forming apparatus, the developing roller 1 is disposed to face an adjusting member that adjusts the amount of developer carried on the developing roller 1. The adjusting member includes a developing blade installed in parallel with the outer periphery of the developing roller 1, and a seal portion that contacts the end portion of the developing roller 1 at both ends of the developing blade and prevents leakage of the developer. It is installed so as to be in sliding contact with the end protection layer 25 of the developing roller 1.

  In the present embodiment, the image forming apparatus is not limited to the above aspect, and the developing roller 1 can be applied to various known image forming apparatuses.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

Example 1
<Formation of elastic layer>
An electroless nickel-plated shaft (SUM22, diameter 7.5 mm, length 275 mm) was washed with ethanol, and a silicone primer (trade name “Primer No. 16”, manufactured by Shin-Etsu Chemical Co., Ltd.) was formed on the surface. ) Was applied. The shaft body coated with the primer was baked at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the outer peripheral surface of the shaft body.

Next, a silicone rubber composition for forming an elastic layer was prepared as follows.
That is, 100 parts by mass of dimethylpolysiloxane (degree of polymerization 300) blocked at both ends with dimethylvinylsiloxy groups, and hydrophobized fumed silica having a BET specific surface area of 110 m ² / g (manufactured by Nippon Aerosil Co., Ltd., R -972) 1 part by mass, 40 parts by mass of diatomaceous earth (Oplite W-3005S, manufactured by Hokuaki Diatomite) having an average particle diameter of 6 μm and a bulk density of 0.25 g / cm ³ , acetylene black (Denka Black HS-100, 5 parts by mass (manufactured by Denki Kagaku Kogyo Co., Ltd.) and 20 parts by mass of metal silicon particles were put in a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This was returned to the planetary mixer again, and as a crosslinking agent, 2.1 parts by mass of methyl hydrogen polysiloxane having a Si—H group at both ends and side chains (polymerization degree 17, Si—H amount 0.0060 mol / g). Addition of 0.1 part by mass of ethynylcyclohexanol and 0.1 part of platinum catalyst (Pt concentration 1%) as reaction control agents, and stirring and kneading for 15 minutes, addition curable liquid conductive silicone rubber composition A product was prepared.

  An elastic layer having an outer diameter of 20 mm was formed on the outer peripheral surface of the shaft body by liquid injection molding using the prepared addition-curable liquid conductive silicone rubber composition. In the injection molding, the addition-curable liquid conductive silicone rubber composition was cured by heating at 150 ° C. for 10 minutes.

<Formation of coat layer>
Next, a resin composition for forming a coat layer was prepared as follows.
That is, 28 parts by mass of a linear polyester polyol, 14 parts by mass of hexamethylene diisocyanate (trade name “Duranate TPA-100”, manufactured by Asahi Kasei), 0.03 parts by mass of dibutyltin dilaurate (manufactured by Showa Chemical Co., Ltd.), carbon black (product) Name “Toca Black # 5500” manufactured by Tokai Carbon Co., Ltd.) 5 parts by mass, small diameter urethane beads (average particle size 3 μm, trade name “Art Pearl C-1000 Transparent” manufactured by Negami Kogyo Co., Ltd.) 4 parts by mass, and solvent As a mixture, 5 parts by mass of butyl acetate was mixed to prepare a resin composition (a-1).

  The prepared resin composition (a-1) was applied to the outer peripheral surface of the elastic layer by a spray coating method, and heated at 160 ° C. for 30 minutes to form a coating layer having a thickness of 20 μm.

<Formation of edge protective layer>
Subsequently, the resin composition for forming an edge part protective layer was prepared as follows.
That is, 17 parts by mass of a tetrafluoroethylene copolymer (trade name “Zeffle GK510”, manufactured by Daikin Industries), 9 parts by mass of hexamethylene diisocyanate (trade name “Duranate TPA-100”, manufactured by Asahi Kasei), silicone resin ( Trade name “KR-5235”, manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts by mass, carbon black (trade name “Toka Black # 5500”, manufactured by Tokai Carbon Co., Ltd.) 4.5 parts by mass, silica (trade name “ACEMATT OK-607”) And 2 parts by mass of Degussa) and 72 parts by mass of butyl acetate (solvent) were mixed to prepare a resin composition (b-1).

  The outer peripheral surface of the coat layer was subjected to masking treatment except for a range of 10 mm from both ends of the coat layer toward the center side (hereinafter, “both ends”). The resin composition (b-1) was applied to both ends not subjected to masking treatment by a spray coating method and heated at 160 ° C. for 30 minutes to form an end protective layer having a thickness of 2 μm.

  With the above method, the developing roller A-1 of Example 1 was produced. The following evaluation was performed on the produced developing roller A-1.

<Developer melting evaluation>
The produced developing roller was attached to a contact type monochrome image forming apparatus (trade name “HL-6180DW”, manufactured by Brother Industries, Ltd.). Note that the developer and developer regulating member attached to the contact type monochrome image forming apparatus were used as the developer and developer regulating member. The charging characteristics of this developer were positive.
The environment in the contact type monochrome image forming apparatus equipped with the developing roller is adjusted to a high humidity environment with a temperature of 30 ° C. and a relative humidity of 80%, and a solid white image is continuously printed on the entire surface of one side of A4 paper. The image forming apparatus was disassembled every time, and it was visually confirmed whether or not the developer melted from the notch of the blade of the developing device and leaked to the outside.
The evaluation is “A” when the developer does not melt at the stage where 8 hours or more have elapsed from the start of operation and no developer leakage is confirmed, but there is a sign that the developer melts in 5 to 8 hours. The case where the developer did not leak and there was no problem in use was designated as “B”, and the case where the developer was melted in less than 5 hours and leakage of the developer was confirmed was designated as “C”.

<Surface thickness evaluation>
The produced developing roller was attached to a contact type monochrome image forming apparatus (trade name “HL-6180DW”, manufactured by Brother Industries, Ltd.). Note that the developer and developer regulating member attached to the contact type monochrome image forming apparatus were used as the developer and developer regulating member. The charging characteristics of this developer were positive.
The environment in the contact type monochrome image forming apparatus equipped with the developing roller is adjusted to a low humidity environment with a temperature of 10 ° C. and a relative humidity of 20%, and a solid white image is continuously printed on the entire surface of one side of A4 paper for 1 hour. The image forming apparatus was disassembled every time, and the surface layer of the developing roller was scraped at the toner seal contact portion of the developing apparatus, and it was visually confirmed whether or not there was a crack or the like.
Evaluation is “A” when the surface layer of the developing roller did not crack after 25 hours from the start of operation, and the surface layer of the developing roller was cracked in less than 25 hours, and the surface layer of the developing roller was shaved. The case where it was confirmed that it was confirmed as “C”.

  The evaluation results are as shown in Table 1.

(Example 2)
17 parts by mass of a tetrafluoroethylene copolymer (trade name “Zeffle GK510”, manufactured by Daikin Industries), 9 parts by mass of hexamethylene diisocyanate (trade name “Duranate TPA-100”, manufactured by Asahi Kasei), silicone resin (trade name) "KR-5234", manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts by mass, carbon black (trade name "Toka Black # 5500", manufactured by Tokai Carbon Co., Ltd.) 4.5 parts by mass, and 72 parts by mass of butyl acetate (solvent) Thus, a resin composition (b-2) was prepared.

  A developing roller (developing roller A-2) was prepared in the same manner as in Example 1 except that the resin composition (b-2) was used as the resin composition for forming the end protective layer. . The produced developing roller A-2 was evaluated in the same manner as in Example 1.

(Example 3)
17 parts by mass of ethylene trifluoride copolymer (trade name “Lumiflon LF200”, manufactured by Asahi Glass Co., Ltd.), 9 parts by mass of hexamethylene diisocyanate (trade name “Duranate TPA-100”, manufactured by Asahi Kasei Co., Ltd.), silicone resin (trade name “ "KR-5235", manufactured by Shin-Etsu Chemical Co., Ltd.) 3 parts by mass, carbon black (trade name "Toka Black # 5500", manufactured by Tokai Carbon Co., Ltd.) 4.5 parts by mass, silica (trade name "ACEMATT OK-607", Degussa 2 parts by mass) and 72 parts by mass of butyl acetate (solvent) were mixed to prepare a resin composition (b-3).

  A developing roller (developing roller A-3) was produced in the same manner as in Example 1 except that the resin composition (b-3) was used as the resin composition for forming the end protective layer. . The produced developing roller A-3 was evaluated in the same manner as in Example 1.

(Comparative Example 1)
An elastic layer and a coating layer were formed in the same manner as in Example 1, and thus a developing roller B-1 of Comparative Example 1 was produced. The developing roller B-1 was not provided with an end protective layer. The developing roller B-1 was evaluated in the same manner as in Example 1.

(Comparative Example 2)
An elastic layer was formed in the same manner as in Example 1 except that the compounding amount of the metal silicon particles was changed to 30 parts by mass. Next, a coating layer was formed in the same manner as in Example 1 to produce a developing roller B-2 of Comparative Example 2. The developing roller B-2 was not provided with an end protective layer. The developing roller B-2 was evaluated in the same manner as in Example 1.

  DESCRIPTION OF SYMBOLS 1 ... Developing roller, 10 ... Shaft body, 20 ... Roller main body, 21 ... Elastic layer, 23 ... Coat layer, 25 ... End part protective layer.

Claims (6)

A shaft,
A roller body provided on the outer peripheral surface of the shaft body;
With
The roller body, a cylindrical elastic layer, and a coating layer covering the outer peripheral surface of the elastic layer, provided on the outer peripheral surface of the coating layer at both ends their respective in axial direction of the roller body Including an end protective layer,
The elastic layer contains silicone rubber and metal silicon particles;
The coat layer contains a urethane resin;
The end protective layer contains a fluorine-containing resin as a matrix ,
Development roller.   The developing roller according to claim 1, wherein the elastic layer has a thermal conductivity of 0.2 to 0.7 W / mK.   The developing roller according to claim 1, wherein the resin material constituting the coating layer has an elongation percentage of 350% or more.   The developing roller according to any one of claims 1 to 3, wherein the urethane resin is a copolymer of a polyol component and a polyisocyanate component, and the number average molecular weight of the polyol component is 800 to 15000.   The developing roller according to claim 1, wherein the fluororesin has at least one structural unit selected from the group consisting of an ethylene tetrafluoride unit and an ethylene trifluoride unit.   An image forming apparatus comprising the developing roller according to claim 1.

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