JP2021196450A - Developing roller - Google Patents

Abstract

To provide a developing roller that can efficiently release frictional heat with a toner seal and can prevent filming caused by developer to obtain a high-quality image.SOLUTION: A developing roller 10 comprises: a hollow base material 11 that is made of first metal, a pair of shaft members 13 that are fixed to both ends in a longitudinal direction Y of the hollow base material 11, and an elastic layer 18 that is provided on the outer periphery of the hollow base material 11. The shaft member 13 has a main body part 15 that is inserted into an inner space 12 of the hollow base material and a shaft body 14 that is provided at the center of axis, and both the main body part 15 and the shaft body 14 are made of second metal.SELECTED DRAWING: Figure 2

Description

The present invention relates to a developing roller.

In electrophotographic devices such as copiers and printers and image forming devices such as electrostatic recording devices, a developing operation is performed in which a developer is supplied to an image carrier carrying an electrostatic latent image to visualize the electrostatic latent image. Will be done. A developing roller that is in contact with an image carrier and supplies a developer is generally provided with a shaft and a semi-conductive elastic layer provided around the shaft.

In such an image forming apparatus, the melting temperature of the developer is being lowered so as to be fixed on the recording paper at a lower temperature as the power consumption is lowered and the speed is increased. Therefore, when used for a long period of time, the developer may be melted by the heat of the developing roller, or the developer may be deposited (referred to as filming) on the surface of the developing roller.

Therefore, in order to improve the heat diffusion in the surface layer of the developing roller, for example, Patent Document 1 proposes a developing roller provided with a high thermal conductivity rubber. Further, Patent Document 2 discloses a developing roller in which a shaft member is composed of a resin flange portion and a shaft portion in order to prevent heat generated by a rotary gear from being conducted to the developing roller.

JP-A-2018-59993 Japanese Unexamined Patent Publication No. 2018-159723

In an image forming apparatus such as an electrostatic recording device, a cylindrical toner seal is provided on the outer periphery of the end portion of the developing roller, and frictional heat due to sliding friction is generated between the toner seal and the developing roller. The toner melted by the frictional heat is cooled and fixed during the stop period of the developing roller, creating a gap between the toner seal and the developing roller, and the toner leaks to the outside through the gap, resulting in poor image quality. There's a problem.
The present invention has been made in view of the above circumstances, and provides a developing roller capable of efficiently dissipating frictional heat with a toner seal, suppressing filming of a developer, and obtaining a high-quality image. The purpose is.

The present invention comprises a hollow base material made of a first metal, a hollow shaft having a pair of shaft members fixed to both ends in the longitudinal direction of the hollow base material, and an elastic layer provided on the outer periphery of the hollow base material. The developing roller is provided, and the shaft member has a main body portion inserted into the inner space of the hollow base material and a shaft body provided at the center of the shaft, and the main body portion and the shaft body are both second. It is a developing roller made of metal.

The thickness of the elastic layer is preferably 200 μm or more and 2500 μm or less.

The elastic layer preferably does not contain a heat conductive agent.

It is preferable that the first metal is aluminum and the second metal is aluminum or iron.

It is preferable that the main body and the shaft are integrally molded.

A coating layer may be further provided on the outer periphery of the elastic layer.

The shaft member is preferably provided on the outside of the main body portion and has a flange portion for locking the shaft member at the end portion of the hollow base material.

According to the developing roller of the present invention, the frictional heat with the toner seal can be efficiently dissipated, the filming of the developing agent can be suppressed, and a high-quality image can be obtained.

It is a front view which shows one Embodiment of the development roller of this invention. FIG. 3 is a cross-sectional view showing one end of the AA cross section in FIG. It is sectional drawing which provided the toner seal on the outer periphery of the end portion of the developing roller of this invention. It is sectional drawing which shows the other embodiment of the developing roller of this invention. It is sectional drawing which shows the other embodiment of the developing roller of this invention. It is a graph which shows the time-dependent change of the surface temperature of the developing roller of an Example and a reference example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are presented for purposes of illustration only, and the present invention is not limited to the embodiments shown below.

[Developing roller]
As shown in FIGS. 1 and 2, the developing roller 10 of the present invention has a hollow base material 11 made of a first metal and a pair of shaft members 13 fixed to both ends of the hollow base material 11 in the longitudinal direction Y. A hollow shaft 17 and an elastic layer 18 provided on the outer periphery of the hollow base material 11 are provided.
Then, as shown in FIG. 2, the shaft member 13 has a main body portion 15 inserted into the inner space 12 of the hollow base material 11, and a shaft body 14 provided at the center of the shaft.
The main body portion 15 and the shaft body 14 are both made of a second metal.
The details of each configuration will be described below.

<Hollow shaft>
The hollow shaft 17 has a hollow base material 11 made of a first metal and a pair of shaft members 13 fixed to both ends of the hollow base material 11 in the longitudinal direction Y.

(Hollow base material)
The hollow base material 11 is made of a first metal. As the first metal, aluminum (including aluminum alloy), iron, stainless steel, brass, sulfur free-cutting steel (SUM), and nickel and zinc-plated surfaces of these first metals shall be used. Can be done. Aluminum having good heat conduction is more preferable because it facilitates the frictional heat generated between the developing roller 10 and the toner seal 30 (see FIG. 3) to escape in the longitudinal direction Y of the hollow base material 11. Aluminum is more preferable from the viewpoint of reducing the weight of the developing roller 10.
The hollow base material 11 may be made of one material or may be made of two or more materials. Further, the hollow base material 11 may have a laminated structure.

The outer peripheral surface of the hollow base material 11 may be subjected to a cleaning treatment, a degreasing treatment, a primer treatment, or the like in order to improve the adhesiveness with the elastic layer 18.

The length of the hollow base material 11 in the longitudinal direction Y 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 length of the hollow base material 11 in the axial direction is preferably 200 mm or more and 400 mm or less, and more preferably 230 mm or more and 300 mm or less.

The outer diameter of the hollow base material 11 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 outer diameter (diameter of the circumscribed circle) of the hollow base material 11 is preferably 8 mm or more and 30 mm or less, and more preferably 10 mm or more and 20 mm or less.

The thickness of the hollow base material 11 is preferably 0.5 mm or more and 2.0 mm or less, and more preferably 0.7 mm or more and 1.2 mm or less.

(Shaft member)
The pair of shaft members 13 are fixed to both ends of the hollow base material 11 in the longitudinal direction Y. The pair of shaft members 13 has a main body portion 15 inserted into the inner space 12 of the hollow base material 11, and a shaft body 14 provided at the center of the shaft. The main body portion 15 is fixed to the inner wall of the hollow base material 11 by adhesive, press-fitting, fitting, or welding.
The main body 15 and the shaft 14 are both made of a second metal. As the second metal, the metal mentioned in the first metal can be used, and aluminum or iron is more preferable. The main body portion 15 of the shaft member 13 and the hollow base material 11 may be made of the same metal or may be made of different metals.
The main body portion 15 and the shaft body 14 may be manufactured by integral molding, or may be manufactured from separate members. If they consist of separate members, they are preferably fixed with a metal adhesive, metal welding. Further, when the main body portion 15 and the shaft body 14 are made of separate members, the metal of the main body portion 15 and the metal of the shaft body 14 may be the same or different.

As shown in FIG. 1, the shaft member 13 may have a flange portion 16 on the outside of the main body portion 15, and the flange portion 16 has a larger outer diameter than the main body portion 15 and has an end portion of the hollow base material 11. It has a role of locking the shaft member 13 so as not to enter the inner space 12. It is preferable that the main body portion 15, the flange portion 16 and the shaft body 14 are all made of a second metal and are integrally formed by a mold.

In the shaft member 13 of the present invention, since the main body portion 15 and the shaft body 14 are both made of the second metal, the frictional heat generated between the surface of the developing roller 10 and the toner seal 30 is transferred from the main body portion 15. It can be efficiently diffused to the outside through the shaft body 14. As a result, melting of the toner can be prevented, and filming and toner leakage can be prevented even on the surface of the developing roller, so that a high-quality image can be obtained.

As shown in FIG. 4, the main body portion 15 in another embodiment is provided with a plurality of convex portions 22a on the outer peripheral surface. In this case, it is preferable that the concave portion 21a is provided on the inner wall of the hollow base material 21 in contact with the main body portion 15. By fitting the concave portion 21a of the hollow base material 21 and the convex portion 22a of the main body portion 15, it is possible to prevent the shaft member 13 and the hollow base material 21 from being displaced due to rotation.

<Elastic layer>
The elastic layer 18 is formed by providing the rubber composition on the outer peripheral surface of the hollow base material 11 and heating and curing the elastic layer 18.

Examples of the rubber of the elastic layer 18 include silicone or silicone-modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, and chloroprene rubber. , Butyl rubber, epichlorohydrin rubber, urethane rubber, fluororubber and the like.
Of these, silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber can reduce compression set, is excellent in flexibility in a low temperature environment, and has heat resistance and charging characteristics. It is particularly preferable in that it is excellent in such things as. Examples of the silicone rubber include crosslinked products of organopolysiloxane such as dimethylpolysiloxane and diphenylpolysiloxane.

Examples of the silicone rubber composition include an addition-curable mirrorable conductive silicone rubber composition and an addition-curable liquid conductive silicone rubber composition.

-Additional curable mirrorable conductive silicone rubber composition-
The addition-curable mirabable conductive silicone rubber composition contains, for example, (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C) a conductivity-imparting agent. It's okay.
R ¹ _n SiO _{(4-n) / 2} ... (1)
In the formula (1), n represents a positive number of 1.95 or more and 2.05 or less. Further, R ¹ indicates a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 12 or less, and more preferably 1 or more and 8 or less.

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

(A) The organopolysiloxane has a molecular chain terminal such as a trialkylsilyl group such as a trimethylsilyl group, a dialkylaralkylsilyl group such as a dimethylvinylsilyl group, a dialkylhydroxysilyl group such as a dimethylhydroxysilyl group, or a trivinylsilyl group. It is preferably sealed with a trialal kill silyl group or the like.

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

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

The kinematic viscosity of (A) organopolysiloxane at 25 ° C. is preferably 100 cSt or more, and more preferably 100,000 cSt or more and 10,000,000 cSt or less. Further, the degree of polymerization of (A) organopolysiloxane is preferably, for example, 100 cSt or more, and more preferably 3000 cSt or more and 10000 cSt or less.

Examples of the filler (B) include silica-based fillers. Examples of the silica-based filler include fumes silica, precipitated silica and the like.

As the silica-based filler, a surface-treated silica-based filler surface-treated with the silane coupling agent ^{represented by R 2} Si (OR ³ ) _{3 can be preferably used.} Here, R ² may be a group having a vinyl group or an amino group, and may be, for example, a glycidyl group, a vinyl group, an aminopropyl group, a methacryoxy group, an N-phenylaminopropyl group, a mercapto group or the like. R ³ may be an alkyl group, for example, a methyl group, an ethyl group, or the like. The silane coupling agent can be easily obtained, for example, under the trade names "KBM1003" and "KBE402" manufactured by Shin-Etsu Chemical Co., Ltd. The surface-treated silica-based filler can be obtained by treating the surface of the silica-based filler with a silane coupling agent according to a conventional method. As the surface-treated silica-based filler, a commercially available product may be used, for example, J.A. M. Examples thereof include the product name "Zeothix 95" manufactured by HUBER Co., Ltd.

The blending amount of the silica-based filler is preferably 11 parts by mass or more and 39 parts by mass or less, and more preferably 15 parts by mass or more and 35 parts by mass or less with respect to 100 parts by mass of (A) organopolysiloxane. The average particle size of the silica-based filler is preferably 1 μm or more and 80 μm or less, and more preferably 2 μm or more and 40 μm or less. The average particle size of the silica-based filler can be measured as the median diameter using a particle size distribution measuring device by a laser light diffraction method.

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

The addition-curable mirabable conductive silicone rubber composition may further contain additives other than (A) to (C). Additives include, for example, auxiliaries (chain extenders, crosslinkers, etc.), catalysts, dispersants, foaming agents, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, etc. Examples thereof include emulsifiers, heat resistance improvers, ion conductive agents, flame retardant improvers, acid receiving agents, thermal conductivity improvers, mold release agents, solvents and the like.

Specific examples of the additive include (A) both-terminal silanol group encapsulation such as (A) dimethylsiloxane oil having a lower degree of polymerization than organopolysiloxane, polyether-modified silicone oil, silanol, diphenylsilanediol, and α, ω-dimethylsiloxanediol. Dispersants such as low molecular weight siloxane and silane can be mentioned. Specific examples of the additive include heat resistance improvers such as iron octylate, iron oxide, and cerium oxide. Further, as the additive, various carbon functional silanes, various olefin elastomers, and the like for improving adhesiveness, molding processability, and the like may be used.

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

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

As R ⁴ , the same group as that exemplified as R ^{1 can be exemplified.} Also, at least two of R ⁴ in one molecule is an alkenyl group, R ⁴ other than it is preferably an alkyl group. The alkenyl group is preferably a vinyl group, and the alkyl group is preferably a methyl group. Further ^{, for example, 90% or more of R 4} may be an alkyl group (preferably a methyl group). (D) The content of the alkenyl group in the organopolysiloxane is preferably, for example, 1.0 × 10 ^-6 mol / g or more and 5.0 × 10 ^-3 mol / g or less, preferably 5.0 × 10 ^{−. It is more preferably 6} mol / g or more and 1.0 × 10 ^-3 mol / g or less.

(D) The organopolysiloxane is preferably liquid at 25 ° C., preferably has a viscosity at 25 ° C. of 100 mPa · s or more and 1000000 mPa · s or less, and more preferably 200 mPa · s or more and 100,000 mPa · s or less. preferable. Further, the average degree of polymerization of (D) organopolysiloxane is preferably 100 or more and 800 or less, and more preferably 150 or more and 600 or less.

As the (E) organohydrogenpolysiloxane, the compound represented by the following average composition formula (3) is suitable.
R ⁵ _b H _c SiO _{(4-b-c) / 2} ... (3)
In formula (3), b indicates a positive number of 0.7 or more and 2.1 or less, c indicates a positive number of 0.001 or more and 1.0 or less, and bc indicates 0.8 or more and 3.0 or less. Is. Further, R ⁵ may be the same or different, a substituted or unsubstituted monovalent hydrocarbon group. The number of carbon atoms of the hydrocarbon group is preferably 1 or more and 10 or less. As R ⁵ , the same group as that exemplified as R ^{1 can be exemplified.}

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

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

Examples of the organohydrogenpolysiloxane (E) include a double-ended trimethylsiloxy group-blocked methylhydrogenpolysiloxane, a double-ended trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, and a double-ended dimethylhydrogensiloxy group-blocked. Dimethylpolysiloxane, dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer at both ends, trimethylsiloxy group-blocked methylhydrogensiloxane at both ends -Diphenylsiloxane-dimethylsiloxane copolymer, (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit, and (CH ₃ ) ₂ HSiO _1/2 unit and SiO _{4/2. Examples} thereof include a copolymer composed of a unit and (C ₆ H ₅ ) SiO 3/2 unit.

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

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

(F) The average particle size of the filler is preferably 1 μm or more and 30 μm or less, and more preferably 2 μm or more and 20 μm or less. (F) When the average particle size of the filler is 1 μm or more, the change in volume resistivity with time is further suppressed. Further, when the average particle size of the (F) filler is 30 μm or less, the elastic layer 18 having further excellent durability can be obtained. The average particle size of the filler (F) can be measured as a median diameter using a particle size distribution measuring device by a laser light diffraction method.

(F) the bulk density of the filler is preferably at 0.1 g / cm ³ or more 0.5 g / cm ³ or less, and more preferably less 0.15 g / cm ³ or more 0.45 g / cm ³ .. (F) By adjusting the bulk density of the filler to the above range, the compression set can be further lowered, the change in volume resistivity with time is further suppressed, and the elastic layer 18 having further excellent durability. Can be obtained. (F) The bulk density of the filler can be determined based on the method of measuring the apparent specific gravity of JIS K 6223.

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

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

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

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

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

The addition-curable liquid conductive silicone rubber composition may further contain additives other than (D) to (H). Additives include, for example, auxiliaries (chain extenders, crosslinkers, etc.), foaming agents, dispersants, antioxidants, antioxidants, pigments, colorants, processing aids, softeners, plasticizers, emulsifiers, etc. Examples thereof include an ion conductive agent, a heat resistance improving agent, a flame retardant improving agent, an acid receiving agent, a thermal conductivity improving agent, 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 weight siloxane ester, polyether-modified silicone oil, silanol, and phenylsilanediol. Further, heat resistance improvers such as iron octylate, iron oxide and cerium oxide can be mentioned. Further, various carbon functional silanes, various olefin elastomers and the like for improving adhesiveness, molding processability and the like may be used. Further, a halogen compound or the like that imparts flame retardancy may be used.

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

The elastic layer 18 is formed on the outer peripheral surface of the hollow base material 11 by performing heat curing and molding simultaneously or continuously by a known molding method. The method for curing the rubber composition may be any method as long as the heat required for curing the rubber composition can be applied, and the method for forming the elastic layer 18 is particularly limited to continuous vulcanization by extrusion molding, pressing, mold molding by injection, and the like. It is not something that will be done. For example, when the rubber composition is an addition-curable mirable conductive silicone rubber composition, for example, extrusion molding or the like can be selected, and the rubber composition is an addition-curable liquid conductive silicone rubber composition. In some cases, for example, a molding method using a mold can be selected.

The heating temperature at which the rubber composition is cured is preferably 100 ° C. or higher and 500 ° C. or lower, and more preferably 120 ° C. or higher and 300 ° C. or lower in the case of the addition-curing type mirable conductive silicone rubber composition. The heating time is preferably several seconds or more and 1 hour or less, and more preferably 10 seconds or more and 35 minutes or less. In the case of the addition-curable liquid conductive silicone rubber composition, the heating temperature is preferably 100 ° C. or higher and 300 ° C. or lower, and more preferably 110 ° C. or higher and 200 ° C. or lower. The heating time is preferably 5 minutes or more and 5 hours or less, and more preferably 5 minutes or more and 30 minutes or less. Further, if necessary, secondary vulcanization may be carried out. In the case of the addition-curing type mirabable conductive silicone rubber composition, for example, curing conditions of about 1 hour or more and 20 hours or less at 100 ° C. or higher and 200 ° C. or lower are selected. Further, in the case of the addition-curing type liquid conductive silicone rubber composition, for example, curing conditions of about 2 hours or more and 70 hours or less at 120 ° C. or higher and 250 ° C. or lower are selected. Further, the rubber composition can be easily foamed and cured by a known method to easily form a sponge-like elastic layer having bubbles.

The thickness of the elastic layer 18 is not particularly limited, and is preferably 0.1 mm or more and 6 mm or less, and more preferably 0.7 mm or more and 4 mm or less. The thickness in the present specification indicates the thickness in the direction perpendicular to the longitudinal direction Y of the developing roller 10.

The outer diameter of the elastic layer 18 is not particularly limited, and is preferably 6 mm or more and 25 mm or less, and more preferably 7 mm or more and 21 mm or less.

The outer peripheral surface of the elastic layer 18 is subjected to surface treatment such as primer treatment, corona treatment, plasma treatment, excimer treatment, UV treatment, itro treatment, and frame treatment for the purpose of improving the adhesiveness with the coating layer. good.

The method of forming the elastic layer 18 is not particularly limited. For example, the elastic layer 18 may be formed by a method such as extrusion molding or LIMS molding of the silicone rubber composition. Further, the elastic layer 18 may be formed by grinding and polishing an elastic body (cured product of a silicone rubber composition) formed on the hollow base material 11.

(Other configurations)
As shown in FIG. 5, the developing roller 10 of the present invention may be further provided with a coating layer 19 on the outer periphery of the elastic layer 18. In the coating layer 19, the elastic layer 18 or the outer peripheral surface of the primer layer formed as desired is coated with the coating resin composition, and then the coated resin composition for the coating layer is heat-cured. Is formed. The coating layer 19 is preferably made of urethane resin. The urethane resin is preferably a polymer of a polyol component and a polyisocyanate component.

The thickness of the coating layer 19 is not particularly limited, and is preferably 13 μm or more, more preferably 17 μm or more, for example. By making the coating layer 19 thicker, deterioration such as wear and tear is suppressed more remarkably, and there is a tendency that higher durability can be obtained. The thickness of the coating layer 19 is preferably, for example, 100 μm or less, and more preferably 50 μm or less.

[Example 1]
A hollow shaft was produced as follows, and an elastic layer was formed on the outer periphery of the hollow shaft to produce a developing roller.
(Hollow shaft)
-Preparation of hollow base material-
It has a cylindrical shape with an outer diameter of 18 mm, a thickness of 1 mm, and a length of 235 mm in the axial direction, and has an inner diameter of 16 mm. A hollow base material having an inner diameter expanded region (length in the axial direction of 12 mm) formed at both ends of the region class “P6”) was made of aluminum.

-Manufacturing of shaft member-
A shaft member having a main body portion having an outer diameter of 16 mm and a length of 19 mm in the axial direction, a flange portion having an outer diameter of 18 mm and a thickness of 1 mm, and a shaft body having an outer diameter of 7.5 mm and a length of 23 mm in the axial direction is made of aluminum. A shaft member was manufactured by integral molding with a mold using the above.

Finally, the main body of the shaft member was inserted into the hollow base material and fixed by welding to complete the hollow shaft.

(Formation of primer layer)
The hollow shaft thus produced was washed with ethanol, and a silicone-based primer (trade name "Primer No. 16", manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface thereof. The primer-treated hollow shaft was fired at a temperature of 150 ° C. for 10 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer on the surface of the hollow substrate.

(Formation of elastic layer)
Next, a silicone rubber composition for forming an elastic layer was prepared as follows.
Hydrophobicized fumed silica (trade name "R-972") having 100 parts by mass of dimethylpolysiloxane (polymerization degree 300) with both ends sealed with a dimethylvinylsiloxy group and a BET specific surface area of 110 m ^{2 / g.} Japan Aerosil Co., Ltd.) 1 part by mass, average particle diameter 6 μm, bulk density 0.25 g / cm ³ diatomaceous soil (trade name "Opreite W-3005S", manufactured by Chuo Silica Co., Ltd.) 40 parts by mass, and acetylene 5 parts by mass of black (trade name "Denka Black HS-100", manufactured by Denka Co., Ltd.) was placed in a planetary mixer, stirred for 30 minutes, and then passed through three rolls once. Returning this to the planetary mixer again, methylhydrogenpolysiloxane having Si—H groups at both ends and side chains (polymerization degree 17, Si—H amount 0.0060 mol / g) 2.1 parts by mass, ethynylcyclohexanol 0.1 part by mass and 0.1 part by mass of a platinum-based catalyst (Pt concentration 1% by mass) were added, and the mixture was stirred for 30 minutes for defoaming and kneading to prepare an addition-curable liquid conductive silicone rubber composition.

The prepared addition-curable liquid conductive silicone rubber composition was injection-molded using a mold to form an elastic body made of a rubber material on the outer peripheral surface of the shaft body. In injection molding, an addition-curable liquid conductive silicone rubber composition was heated at 120 ° C. for 10 minutes to be cured, and secondary vulcanization was performed at 200 ° C. for 4 hours to form an elastic layer having a thickness (outer diameter of 20 mm). ..

(Formation of coating layer)
Next, a resin composition for forming a coating layer was prepared as follows.
The contents (parts by mass) of (a) polyol, (b) isocyanate, (c) surface roughness material, and (d) ionic conductive material in the resin composition for coating layer are shown below. ..

-Resin composition for coating layer-
(A) 28 parts by mass of polyester polyol (b) Hexamethylene diisocyanate (trade name "Duranate TPA-100", manufactured by Asahi Kasei Co., Ltd.) 14 parts by mass (c) Surface roughness material (silica) (trade name "ACEMATT412", Ebony (Made by Japan Co., Ltd.) 3 parts by mass (d) Carbon black (Product name "Toka Black # 5500", manufactured by Tokai Carbon Co., Ltd.)
5 parts by mass

The resin composition for a coating layer was applied to the outer peripheral surface of the elastic layer by a spray coating method and heated at 160 ° C. for 30 minutes to form a coating layer having a layer thickness of 22 μm.

[Reference example]
A developing roller was prepared in the same manner as in Example 1 except that an elastic layer having a thickness of 6.25 mm was provided on a solid shaft having a thickness of 7.5 φ mm.

[evaluation]
For Examples 1 and Reference, the rollers were attached to the toner cartridge TN-62J of a Brother Industries printer. The cartridge was set in a rattling machine equipped with a mechanism to rotate the rollers. When the gear drive input unit was rotated and the roller was rotated at 550 rpm as an acceleration condition, the surface temperature of the area in contact with the toner seal was measured using InfReC R550P manufactured by Nippon Avionics Co., Ltd. The emissivity was 0.95 as a condition of the measuring machine.
The measurement results are shown in FIG.

As shown in FIG. 6, the developing roller of the present invention rose only to about 35 ° C. after 3600 seconds, whereas the reference example rose to about 43 ° C. That is, it was found that the developing roller of the present invention can satisfactorily release the frictional heat with the toner seal.

10 Developing rollers 11, 21 Hollow base material 13 Shaft member 14 Shaft body 15 Main body 16 Flange 17 Hollow shaft 18 Elastic layer 19 Coating layer 21a Concave 22a Convex 30 Toner seal

Claims (7)

Development including a hollow base material made of a first metal, a hollow shaft having a pair of shaft members fixed to both ends in the longitudinal direction of the hollow base material, and an elastic layer provided on the outer periphery of the hollow base material. Laura,
The shaft member has a main body portion inserted into the inner space of the hollow base material and a shaft body provided at the center of the shaft.
A developing roller in which the main body and the shaft are both made of a second metal. The developing roller according to claim 1, wherein the elastic layer has a thickness of 20 μm or more and 2500 μm or less. The developing roller according to claim 1 or 2, wherein the elastic layer does not contain a heat conductive agent. The developing roller according to any one of claims 1 to 3, wherein the first metal is aluminum and the second metal is aluminum or iron. The developing roller according to any one of claims 1 to 4, wherein the main body and the shaft are integrally molded. The developing roller according to any one of claims 1 to 5, wherein a coating layer is further provided on the outer periphery of the elastic layer. The developing roller according to any one of claims 1 to 6, wherein the shaft member is provided on the outside of the main body portion and has a flange portion for locking the shaft member at an end portion of the hollow base material.

Images