JP2011221442A - Conductive roller, developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive roller capable of practically preventing a developer from being adhered to the surface of the roller even if the developer contains an ionic liquid, and to provide a developing device and image forming apparatus that are capable of forming a high-quality image over a long period of time.SOLUTION: There is provided a conductive roller 1 includes an elastic layer 3 formed on the periphery of a shaft 2, and an urethane coat layer 4 formed on the periphery of the elastic layer. The urethane coat layer 4 includes: urethane resin; 1 to 20 pts.mass of at least one kind of ionic liquid selected from a group consisting of pyridinium ionic liquid, amine ion liquid, and ionic liquid that has two hydroxyl groups, per 100 pts.mass of the urethane resin; and 0.1 to 5 pts.mass of fluorine surfactant per 100 pts.mass of the urethane resin. There are also provided a developing device having the conductive roller 1 and developer, and are image forming apparatus having the developing device.

Description

  The present invention relates to a conductive roller, a developing device, and an image forming apparatus. More specifically, even if an ionic liquid is contained, the conductive roller is difficult to adhere to a surface for a long period of time, The present invention relates to a developing device and an image forming apparatus capable of forming a quality image.

  Various image forming apparatuses using an electrophotographic system are employed in printers such as laser printers and video printers, copiers, facsimiles, and multi-function machines thereof. An image forming apparatus using an electrophotographic system includes various types of rollers. Examples of the various rollers include a conductive roller having conductivity or semi-conductivity, and an elastic roller having relatively low hardness. Specifically, the conductive roller includes a charging roller for uniformly charging an image carrier such as a photoconductor, a developing roller for carrying and transporting the developer and supplying the developer to the image carrier, and a developer on the developing roller. Examples thereof include a developer supply roller that is supplied while being charged, and a fixing roller that fixes a developer image transferred to a recording material such as recording paper. These various rollers usually have different characteristics, such as hardness, electrical resistivity, etc., depending on their functions and applications.

  As such a conductive roller, for example, Patent Document 1 discloses a “semiconductive member characterized by containing an ionic liquid”, specifically, “methylimidazolium salt and vinyl monomer or (meth)”. "Charging roll containing acrylate" is described (see Examples).

Patent Document 2 is characterized in that “(A) to (C) as an essential component is used for at least a part of a conductive member, the conductive composition for electrophotographic equipment is characterized in that Conductive member for electrophotographic equipment.
(A) Matrix polymer.
(B) At least one conductive filler selected from the group consisting of metal oxides, metal carbides, and carbon black having a DBP adsorption amount of 100 ml / 100 g or more.
(C) Ionic liquid. Is described. The ionic liquid of Patent Document 2 is specifically “1-ethyl-3-methylimidazolium trifluoroborate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, or 1-hexylpyridinium chloride” ( See Examples).

  Patent Document 3 states that “a material containing a specific quaternary ammonium salt (excluding octyltrimethylammonium salt) represented by the general formula (1a) or (1b) is used as an ionic conductive agent. Charging member ". Specifically, the quaternary ammonium salt is “any one of the four alkyl groups bonded to N is an alkyl group having 4, 6, or 8 carbon atoms, and the remaining three are a methyl group or an ethyl group. A quaternary ammonium salt which is a group (excluding octyltrimethylammonium salt), or any three are alkyl groups having 4, 6, 8 carbon atoms, and the remaining one is a methyl group or an ethyl group. (See column 0011 of Patent Document 3).

  Further, Patent Document 4 describes “a conductive roll characterized in that a conductive rubber member made of a rubber-like elastic body containing at least one ionic liquid as a conductive agent is provided around the core member”. Patent Document 5 states that “a charging member for contact charging having a conductive substrate and a conductive surface layer, and the surface layer is composed of a binder resin and conductive resin particles dispersed in the binder resin. The surface roughness of the surface is 3 μm or more and 20 μm or less in terms of Rzjis, and the resin particles contain an ionic conductive agent, and “Charging portion characterized in that the average particle diameter is 1 μm or more and 30 μm or less” is described.

JP 2004-191655 A Japanese Patent Laid-Open No. 2005-220317 Japanese Patent No. 3804476 JP 2003-202722 A JP 2008-276022 A

  By the way, the developing roller is usually attached to the developing device in a state where the outer peripheral surface is in contact with the developer stored so as not to leak outside. The developing roller holds a predetermined amount of charged developer on the surface, and supplies the developer to the image carrier that is in contact with the developing roller.

  However, when an image forming apparatus including such a developing device is operated for a long period of time, a part of the developer may melt and adhere to the surface of the developing roller. When the developer adheres to the surface of the developing roller as described above, a predetermined amount of developer cannot be supplied to the image carrier, and the image quality is deteriorated. Further, the developer may leak from the developing device. In particular, according to the study by the present inventors, it has been newly found that when the developing roller contains an ionic liquid, the developer tends to adhere to the surface thereof. It has been newly confirmed that when a developing roller containing a liquid is provided, image quality deteriorates and developer leaks even in a relatively short time.

  An object of the present invention is to provide a conductive roller in which a developer is difficult to adhere to a surface for a long period of time even if it contains an ionic liquid.

  An object of the present invention is to provide a developing device and an image forming apparatus capable of forming a high-quality image over a long period of time.

  As a result of intensive studies, the inventors of the present invention have the effect that the ionic liquid exerts even when the ionic liquid is contained when a predetermined amount of the fluorosurfactant is contained in the urethane coat layer of the conductive roller. It has been found that the molten developer hardly adheres to the urethane coat layer without damaging, and the amount of the fixed developer can be remarkably reduced.

Therefore, as means for solving the above problems,
Claim 1 is a conductive roller comprising an elastic layer formed on the outer peripheral surface of the shaft body and a urethane coat layer formed on the outer peripheral surface of the elastic layer, wherein the urethane coat layer is urethane Resin and at least one ionic liquid selected from the group consisting of a pyridinium-based ionic liquid, an amine-based ionic liquid, and an ionic liquid having two hydroxyl groups, with respect to 100 parts by weight of the urethane resin A conductive roller containing 0.1 to 5 parts by mass of a fluorosurfactant with respect to 100 parts by mass of the urethane resin,
The conductive roller according to claim 1, wherein the urethane coat layer has a contact angle of hexadecane of 45 to 75 °.
The conductive roller according to claim 1 or 2, wherein the urethane coat layer has a contact angle larger than a contact angle of a developer contacting or carrying the surface of the urethane coat layer. ,
A fourth aspect of the present invention is a developing device comprising the conductive roller according to any one of the first to third aspects and a developer.
The developing device according to claim 4, wherein the developer has a contact angle of hexadecane of 35 to 40 °.
A sixth aspect of the present invention is an image forming apparatus comprising the developing device according to the fourth or fifth aspect.

  The conductive roller according to the present invention includes a urethane resin and a group consisting of 1 to 20 parts by mass of a pyridinium-based ionic liquid, an amine-based ionic liquid, and an ionic liquid having two hydroxyl groups with respect to 100 parts by mass of the urethane resin. The developer comprises a urethane coat layer containing at least one selected ionic liquid and 0.1 to 5 parts by mass of a fluorosurfactant with respect to 100 parts by mass of the urethane resin. Even if it melts, it hardly adheres to the urethane coat layer, and as a result, the developer does not substantially adhere to the surface even if the image forming apparatus is operated for a long period of time. Therefore, according to the present invention, it is possible to provide a conductive roller in which the developer is difficult to adhere to the surface over a long period of time even if it contains an ionic liquid.

  The developing device according to the present invention includes the conductive roller according to the present invention, and the image forming apparatus according to the present invention includes the developing device according to the present invention. Therefore, according to the present invention, it is possible to provide a developing device and an image forming apparatus capable of forming a high-quality image over a long period of time.

FIG. 1 is a perspective view showing an example of a conductive roller according to the present invention. FIG. 2 is a schematic view showing an example of the developing device and the image forming apparatus according to the present invention.

  The conductive roller according to the present invention includes an elastic layer formed on an outer peripheral surface of a shaft body, an outer peripheral surface of the elastic layer, a urethane resin, at least one ionic liquid, and a fluorosurfactant. And a urethane coat layer contained at a predetermined ratio. As described above, when the conductive roller includes the urethane coat layer on the outer peripheral surface of the elastic layer, as described above, it is difficult for the developer to adhere to the surface of the urethane coat layer for a long period of time. When mounted on the developing device, the image forming apparatus can contribute to forming an image without fog even in a low humidity environment where the relative humidity is 20% or less, for example. Further, depending on the type of the ionic liquid, for example, when the ionic liquid is an ionic liquid having two hydroxyl groups, the developer is not easily fixed on the surface of the urethane coat layer for a long period of time, and the image forming apparatus is on standby. Or even if the stop continues for a long period of time, it is possible to substantially suppress the occurrence of white streaks in the image formed thereafter, and this image forming apparatus can contribute to forming a high-quality image.

  In the conductive roller according to the present invention, the urethane resin, the ionic liquid, and the fluorosurfactant may be present independently from each other in the urethane coat layer, and also exist as reactants that have reacted with each other. Or may exist as a complex or the like.

  An example of the conductive roller according to the present invention will be described. As shown in FIG. 1, the conductive roller as an example of the conductive roller according to the present invention includes a shaft body 2, an elastic layer 3 formed on the outer peripheral surface of the shaft body 2, and an outer peripheral surface of the elastic layer 3. And a urethane coat layer 4 formed on the surface.

  The shaft body 2 is basically the same as a shaft body in a conventionally known conductive roller. The shaft body 2 is a so-called “core metal” composed of iron, aluminum, stainless steel, brass, or the like, and has good conductive characteristics. The shaft body 2 may be a shaft body made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin.

  The elastic layer 3 is basically the same as the elastic layer in a conventionally known conductive roller. The elastic layer 3 is formed by curing a conductive composition described later on the outer peripheral surface of the shaft body 2, and preferably has a JIS A hardness of 20 to 70. When the elastic layer 3 has a JIS A hardness (JIS K6301) of 20 to 70, the contact area between the conductive roller 1 and the contacted body can be increased, and the rebound resilience of the elastic layer 3 can be increased. And compression set is excellent.

The elastic layer 3 preferably has a volume resistivity in the range of 10 ¹ to 10 ⁷ Ω · cm and / or an electrical resistivity in the range of 10 ¹ to 10 ⁹ Ω. When the volume resistivity and / or electrical resistivity of the elastic layer 3 is within the above range, the developer is supported and supplied as desired when the conductive roller 1 is mounted on the image forming apparatus, and the desired quality is obtained. It is possible to contribute to forming an image having The volume resistivity can be measured according to a method defined in JIS K6911 (applied voltage is 100 V). The electrical resistivity is, for example, using an electrical resistance meter (trade name: ULTRA HIGH RESISTANCE METER R8340A, manufactured by Advantest Co., Ltd.), placing the conductive roller 1 horizontally, a thickness of 5 mm, a width of 30 mm, and A state in which a gold-plated plate having a length on which the entire urethane coat layer 4 of the conductive roller 1 can be placed is used as an electrode, and a load of 500 g is supported on both ends of the shaft 2 in the conductive roller 1. Then, DC 100V is applied between the shaft body 2 and the electrode, the value of the electric resistance meter after 1 second is read, and the measurement can be performed according to the method of setting this value as the electric resistance value.

  The thickness of the elastic layer 3 is preferably 1 mm or more in that a uniform nip width between the contacted body and the elastic layer 3 can be secured in the contact state with the contacted body. It is particularly preferably 5 mm or more. On the other hand, the upper limit of the thickness of the elastic layer 3 is not particularly limited as long as the outer diameter accuracy of the elastic layer 3 is not impaired. Generally, if the thickness of the elastic layer 3 is excessively increased, the production cost of the elastic layer 3 increases. In consideration of practical production costs, the thickness of the elastic layer 3 is preferably 30 mm or less, and more preferably 20 mm or less. The thickness of the elastic layer 3 is appropriately selected according to the hardness of the elastic layer 3, such as JIS A hardness, in order to achieve a desired nip width.

  The conductive composition forming the elastic layer 3 contains rubber, a conductivity imparting agent, and various additives as desired. Examples of the rubber 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, chloroprene rubber, butyl rubber, and epichlorohydrin. Examples thereof include rubbers such as rubber, urethane rubber, and fluorine rubber. Silicone or silicone-modified rubber or urethane rubber is preferable, and silicone or silicone-modified rubber is particularly preferable in terms of excellent heat resistance and charging characteristics. These rubbers may be liquid or millable. The electroconductivity imparting agent is not particularly limited as long as it has electroconductivity, and examples thereof include electroconductive powder such as electroconductive carbon, carbon for rubber, metal, and electroconductive polymer. Various additives include, for example, auxiliary agents such as chain extenders and crosslinking agents, catalysts, dispersants, foaming agents, anti-aging agents, antioxidants, fillers, pigments, colorants, processing aids, softening agents, Examples thereof include a plasticizer, an emulsifier, a heat resistance improver, a flame retardant improver, an acid acceptor, a heat conductivity improver, a release agent, and a solvent.

  Preferred examples of the conductive composition include addition curable millable conductive silicone rubber compositions and addition curable liquid conductive silicone rubber compositions. The addition-curable millable conductive silicone rubber composition is (A) an organopolysiloxane represented by the following average composition formula (1), (B) a filler, and (C) other than those belonging to the component (B). The conductive material is contained.

R _n SiO _{(4-n) / 2} (1)
Here, R is a substituted or unsubstituted monovalent hydrocarbon group which may be the same or different, preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. Yes, n is a positive number from 1.95 to 2.05.

  R is, for example, 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, an alkenyl such as a vinyl group, an allyl group, a butenyl group and a hexenyl group. Group, aryl groups such as phenyl and tolyl groups, aralkyl groups such as β-phenylpropyl group, and part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms or cyano groups A chloromethyl group, a trifluoropropyl group, a cyanoethyl group, etc. are mentioned.

  In the (A) organopolysiloxane, the molecular chain end is preferably blocked with a trimethylsilyl group, a dimethylvinyl group, a dimethylhydroxysilyl group, a trivinylsilyl group or the like. This organopolysiloxane preferably has at least two alkenyl groups in the molecule, and specifically, 0.001 to 5 mol%, particularly 0.01 to 0.5 mol% of alkenyl groups in R. It is preferable to have a vinyl group. In particular, when a platinum catalyst and an organohydrogenpolysiloxane are used in combination as a curing agent described later, an organopolysiloxane having such an alkenyl group is usually used.

  This (A) organopolysiloxane is obtained by cohydrolyzing and condensing one or more selected organohalosilanes or cyclic polysiloxanes such as siloxane trimers or tetramers. Can be obtained by ring-opening polymerization using an alkaline or acidic catalyst. This (A) organopolysiloxane is basically a linear diorganopolysiloxane, but may be partially branched. Further, it may be a mixture of two or more different molecular structures. This (A) organopolysiloxane usually has a viscosity of 100 cSt or more at 25 ° C., preferably 100,000 to 10,000,000 cSt. The degree of polymerization of (A) organopolysiloxane is usually 100 or more, preferably 3,000 or more, and the upper limit is preferably 100,000, and more preferably 10,000.

The (B) filler is not particularly limited, but a silica-based filler can be used. Examples of the silica-based filler include fumed silica, precipitated silica, etc., and surface-treated silica having a high reinforcing effect, which is surface-treated with a silane coupling agent represented by a general formula RSi (OR ′) _3. System fillers are preferred. Here, R in the general formula is a glycidyl group, vinyl group, aminopropyl group, methacryloxy group, N-phenylaminopropyl group, mercapto group or the like, and R ′ in the general formula is a methyl group or an ethyl group. . The silane coupling agent represented by the general formula can be easily obtained, for example, as trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. Such a silica-based filler surface-treated with a silane coupling agent can be obtained by treating the surface of the silica-based filler according to a conventional method. In addition, a commercial item may be used for the silica type filler surface-treated with the silane coupling agent. M.M. A trade name “Zeothix 95” manufactured by HUBER Co., Ltd. is available. The compounding amount of the silica-based filler is preferably 11 to 39 parts by mass, particularly preferably 15 to 35 parts by mass with respect to 100 parts by mass of the (A) organopolysiloxane. The average particle size of the silica-based filler is preferably 1 to 80 μm, and particularly preferably 2 to 40 μm. The average particle diameter of the silica-based filler can be measured as a weight average value (or median diameter) or the like using, for example, a particle size distribution measuring apparatus such as a laser light diffraction method.

  The (C) conductive material is a conductive material that does not belong to the filler (B), and even if it is made of the same material physically and chemically, the silica-based filling defined as the filler (B) A conductive material having a different form and state from the material belongs to (C) a conductive material. Such an electroconductive material is an electroconductivity imparting component, for example, the said electroconductivity imparting agent is mentioned, Among these, carbon black is preferable. A conductive material may be used independently or may use 2 or more types together. (C) The compounding quantity of an electroconductive material can be 2-80 mass parts with respect to 100 mass parts of said (A) organopolysiloxane.

  The addition-curable millable conductive silicone rubber composition may contain additives and the like within a range that does not impair the object of the present invention. Examples of additives include a curing agent, a colorant, a heat improver such as iron octylate, iron oxide, and cerium oxide, an acid acceptor, a thermal conductivity improver, a release agent, an alkoxysilane, and a degree of polymerization of organopolysiloxane. (A) Lower dimethylsiloxane oil and silanol, such as diphenylsilanediol, α, ω-dimethylsiloxanediol, etc. Examples thereof include various carbon functional silanes for curing and various cured or uncured olefin elastomers that do not inhibit the crosslinking reaction.

The addition-curable liquid conductive silicone rubber composition comprises (D) an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms in one molecule, and (E) bonded to silicon atoms in one molecule. An organohydrogenpolysiloxane containing at least two hydrogen atoms; (F) an inorganic filler having an average particle size of 1 to 30 μm and a bulk density of 0.1 to 0.5 g / cm ³ ; and (G). An addition-curable liquid conductive silicone rubber composition containing a conductivity imparting agent and (H) an addition reaction catalyst can be mentioned.

  As said (D) organopolysiloxane, the compound shown by the following average compositional formula (2) is suitable.

R ¹ _a SiO _{(4-a) / 2} (2)
Here, R ¹ in the average composition formula (2) is the same or different monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and a is It is a positive number in the range of 1.5 to 2.8, preferably 1.8 to 2.5, more preferably 1.95 to 2.02.

R ¹ represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, and one of these hydrogen atoms, as exemplified by R of the organopolysiloxane (A) contained in the addition-curable millable conductive silicone rubber composition. Examples include hydrocarbon groups in which part or all are substituted with halogen atoms or cyano groups. At least two of R ¹ are alkenyl groups, particularly vinyl groups, and preferably 90% or more are methyl groups. Specifically, the alkenyl group content in the organopolysiloxane is 1.0 × 10 ^{−6 to} 5.0 × 10 ⁻³ mol / g, particularly 5.0 × 10 ^{−6 to} 1.0 × 10 ^−. It is preferably ³ mol / g.

  (D) The degree of polymerization of the organopolysiloxane is liquid at room temperature (25 ° C.) (for example, the viscosity at 25 ° C. is 100 to 1,000,000 mPa · s, preferably about 200 to 100,000 mPa · s). The average degree of polymerization is preferably 100 to 800, and particularly preferably 150 to 600.

  The (E) organohydrogenpolysiloxane is represented by the following average composition formula (3), and is at least 2, preferably 3 or more (usually 3 to 200), more preferably 3 to 100 in one molecule. Those having hydrogen atoms bonded to silicon atoms are preferably used.

R ² _b H _c SiO _{(4-b-c) / 2} (3)
Here, R ² in the average composition formula (3) is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. B is 0.7 to 2.1, c is 0.001 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0.

  The content of hydrogen atoms (Si—H) bonded to the silicon atoms is preferably 0.001 to 0.017 mol / g, particularly 0.002 to 0.015 mol / g in the organohydrogenpolysiloxane.

Examples of the organohydrogenpolysiloxane (E) include a trimethylsiloxy group-capped methylhydrogen polysiloxane at both ends, a trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, and a dimethylhydrogensiloxy group-capped dimethyl at both ends. Polysiloxane, both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane diphenylsiloxane-dimethylsiloxane _copolymers, copolymers consisting of _(CH 3) 2 _{HSiO 1/2} units and _{SiO 4/2} units, and, (C _{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.

  The compounding amount of the organohydrogenpolysiloxane (E) is preferably 0.1 to 30 parts by mass, particularly 0.3 to 20 parts by mass with respect to 100 parts by mass of the (D) organopolysiloxane. preferable. (D) The molar ratio of hydrogen atoms bonded to silicon atoms relative to the alkenyl groups of the organopolysiloxane is preferably 0.3 to 5.0, particularly preferably 0.5 to 2.5. .

The (F) inorganic filler is an important component for obtaining low roller permanent set, volume resistivity being stable over time, and sufficient roller durability. The inorganic filler has an average particle size of 1 to 30 μm, preferably 2 to 20 μm, and a bulk density of 0.1 to 0.5 g / cm ³ , preferably 0.15 to 0.45 g / cm ³ . If the average particle size is less than 1 μm, the electrical resistivity may change over time, and if it is greater than 30 μm, the durability of the elastic layer 3 may be reduced. If the bulk density is less than 0.1 g / cm ³ , the compression set may deteriorate and the electrical resistivity may change over time. If it exceeds 0.5 μm, the elastic layer 3 has insufficient strength and is durable. May decrease. The average particle diameter can be determined as a weight average value (or median diameter), for example, using a particle size distribution measuring device such as a laser diffraction method, and the bulk density is a measurement of the apparent specific gravity according to JIS K 6223. It can be determined based on the method.

  Examples of such an inorganic filler (F) include diatomaceous earth, pearlite, mica, calcium carbonate, glass flakes, and hollow filler, among which diatomaceous earth, pearlite, and foamed pearlite are preferable.

  (F) It is preferable that the compounding quantity of an inorganic filler is 5-100 mass parts with respect to 100 mass parts of (D) organopolysiloxane, and it is especially preferable that it is 10-80 mass parts.

  The said (G) electroconductivity imparting agent is the same as that of the said electroconductivity imparting agent, The compounding quantity can be 2-80 mass parts with respect to 100 mass parts of (D) organopolysiloxane.

  Examples of the (H) addition reaction catalyst include platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and an olefin, platinum bisacetoacetate, palladium And catalyst based on rhodium and rhodium. In addition, the compounding quantity of this (H) addition reaction catalyst can be made into a catalyst quantity, for example, as a platinum group metal quantity, it is with respect to the total mass of (D) organopolysiloxane and (E) organohydrogenpolysiloxane. 0.5 to 1,000 ppm is preferable, and about 1 to 500 ppm is particularly preferable.

  This addition curable liquid conductive silicone rubber composition is a low molecular siloxane ester, a silanol, for example, a dispersant such as diphenylsilanediol, an improved heat resistance such as iron oxide, cerium oxide, iron octylate, etc. Agents, various carbon functional silanes that improve adhesion and moldability, halogen compounds that impart flame retardancy, and the like may be included within a range that does not impair the object of the present invention.

  The addition curable liquid conductive silicone rubber composition may have a viscosity of 5 to 500 Pa · s, particularly preferably 5 to 200 Pa · s, at 25 ° C.

  The urethane coat layer 4 is formed as an outermost layer of the conductive roller 1 and is formed by curing a urethane resin composition to be described later on the outer peripheral surface of the elastic layer 3. In addition to the urethane resin, a pyridinium ionic liquid, an amine And containing at least one ionic liquid selected from the group consisting of a ionic liquid and an ionic liquid having two hydroxyl groups in a proportion of 1 to 20 parts by mass with respect to 100 parts by mass of the urethane resin, and a fluorine-based surfactant Is contained at a ratio of 0.1 to 5 parts by mass with respect to 100 parts by mass of the urethane resin.

  In the present invention, when the ionic liquid is an ionic liquid having two hydroxyl groups described later (hereinafter sometimes referred to as a hydroxyl group-containing ionic liquid), the urethane coat layer 4 contains a hydroxyl group-containing ionic liquid. The urethane resin composition is formed by applying and curing the outer peripheral surface of the elastic layer 3. Therefore, this urethane coat layer 4 contains a urethane resin formed with the urethane resin composition and a fluorosurfactant, and this urethane resin is a urethane forming component contained in the urethane resin composition. The hydroxyl group-containing ionic liquid is formed from a polyol and a polyisocyanate other than the hydroxyl group-containing ionic liquid, and the content of the hydroxyl group-containing ionic liquid is 1 to 1 when the total content of the polyol and the polyisocyanate is 100 parts by mass. 20 parts by mass. That is, the urethane coat layer 4 has a polyol, polyisocyanate other than the hydroxyl group-containing ionic liquid, and 1 to 20 parts by mass of the hydroxyl group-containing ionic liquid when the total content of the polyol and the polyisocyanate is 100 parts by mass. Contains 100 parts by mass of a urethane resin obtained by reacting with 0.1 to 5 parts by mass of a fluorosurfactant.

  In addition to the urethane resin, the urethane coat layer 4 may contain various additives usually used in various urethane resin compositions, if desired. As such an additive, for example, a conductivity imparting agent such as carbon black, and other components such as an auxiliary agent in the urethane resin composition described later may be contained as optional components.

  In general, the urethane coat layer 4 preferably has a layer thickness of 0.1 to 50 μm, and more preferably has a layer thickness of 10 to 25 μm.

  The ionic liquid contained in the urethane coat layer 4 is a kind of onium salt, and is a liquid compound having a high conductivity that is in a liquid state at a temperature at least near room temperature, and is also referred to as an “ionic liquid”. The In the present invention, it is important that the ionic liquid is at least one selected from the group consisting of a pyridinium ionic liquid, an amine ionic liquid, and an ionic liquid having two hydroxyl groups among various ionic liquids. . When the ionic liquid is at least one selected from the above group, the occurrence of fogging in a low humidity environment can be substantially suppressed. Therefore, the ionic liquid may be one type or a plurality as long as it is selected from the above group.

  The ionic liquid is a pyridinium-based ionic liquid, an amine-based ionic liquid, or a hydroxyl group-containing ionic liquid.

  The pyridinium-based ionic liquid is an ionic liquid having, as a cation, a pyridinium ion formed by bonding an alkyl group or the like to a nitrogen atom constituting a pyridine ring, and does not have two hydroxyl groups in the molecule. . The alkyl group is preferably a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms which may have a substituent, and is a linear alkyl group having 4 to 18 carbon atoms. It is particularly preferred. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, pentyl, neopentyl, hexyl, and isohexyl groups. Decyl group, dodecyl group, octadecyl group, cyclopentyl group, cyclohexyl group and the like.

  The pyridine ring may be an alkyl group-substituted pyridine ring in which a hydrogen atom bonded to a carbon atom constituting the ring is substituted with an alkyl group. The alkyl group replacing the hydrogen atom may be one or more, and is basically the same as the alkyl group bonded to the nitrogen atom constituting the pyridine ring, and is a linear or branched chain having 1 to 18 carbon atoms. A linear or cyclic alkyl group is preferable, and a linear alkyl group having 4 to 18 carbon atoms is particularly preferable. As the alkyl group-substituted pyridine ring, specifically, α-picoline, β-picoline and γ-picoline having one methyl as the alkyl group, α-ethylpyridine having one ethyl as the alkyl group, β-ethyl Examples include pyridine and γ-ethylpyridine, 2,3-lutidine, 2,4-lutidine, 2,6-lutidine, and 3,4-lutidine having two methyl groups as the alkyl group. Of these, γ-picoline is preferred.

The anion constituting the pyridinium-based ionic liquid is not particularly limited. For example, a halogen ion, BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ (trifluoromethanesulfonyl ion), (CF ₃ SO ₂ ) ₂ N ^- (Bis (trifluoromethanesulfonyl) imide ion: TFSI) etc. are mentioned. Among these, BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ^— and (CF ₃ SO ₂ ) ₂ N ⁻ which are organic acid anions are preferable, and (CF ₃ SO ₂ ) ₂ N ⁻ is particularly preferable.

  Specific examples of the pyridinium-based ionic liquid having a pyridinium ion not substituted with an alkyl group as a cation and a bis (trifluoromethanesulfonyl) imide ion as an anion include, for example, N-propylpyridinium bis (trifluoromethanesulfonyl). ) Imide, N-butylpyridinium bis (trifluoromethanesulfonyl) imide, N-pentylpyridinium bis (trifluoromethanesulfonyl) imide, N-hexylpyridinium bis (trifluoromethanesulfonyl) imide, N-heptylpyridinium bis (trifluoromethanesulfonyl) imide N-octylpyridinium bis (trifluoromethanesulfonyl) imide, N-nonylpyridinium bis (trifluoromethanesulfonyl) imide N- decyl pyridinium bis (trifluoromethanesulfonyl) imide, N- allyl pyridinium bis (trifluoromethanesulfonyl) imide, and the like.

  In addition, as the pyridinium-based ionic liquid in which the pyridinium ion substituted with the alkyl group is a cation and the bis (trifluoromethanesulfonyl) imide ion is an anion, specifically, for example, N-propyl-2-methylpyridinium Bis (trifluoromethanesulfonyl) imide, N-butyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-pentyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-hexyl-2-methylpyridinium bis ( Trifluoromethanesulfonyl) imide, N-heptyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-octyl-2-methylpyridinium bis (trifluoromethanesulfonyl) i N-nonyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-decyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-propyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-pentyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-hexyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N- Heptyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-octyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-nonyl-3- Tylpyridinium bis (trifluoromethanesulfonyl) imide, N-decyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-propyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-butyl-4-methylpyridinium Bis (trifluoromethanesulfonyl) imide, N-pentyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-hexyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-heptyl-4-methylpyridinium bis ( Trifluoromethanesulfonyl) imide, N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-nonyl-4-methylpyridinium bi (Trifluoromethanesulfonyl) imide, N- decyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, and the like. Further, as the pyridinium-based ionic liquid having a pyridinium ion substituted with the alkyl group as a cation and a hexafluorophosphate ion as an anion, specifically, for example, 1-octyl-4-methylpyridinium hexafluoro Examples include phosphate, 1-nonyl-4-methylpyridinium hexafluorophosphate, 1-decyl-4-methylpyridinium hexafluorophosphate, and the like.

  The amine-based ionic liquid is an aliphatic amine-based ionic liquid whose basic skeleton is an ammonium ion in which an alkyl group or the like is bonded to a nitrogen atom of an aliphatic amine compound as a cation. Does not have a hydroxyl group. The alkyl group is basically the same as the alkyl group bonded to the nitrogen atom in the pyridinium-based ionic liquid.

Examples of the aliphatic amine compound include alicyclic amine compounds and aliphatic amine compounds. Examples of ammonium ions composed of these amine compounds include, for example, R ¹ ₄ N ⁺ ions (wherein 4 R ^{1 s} may be the same or different and each have a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms. And a plurality of R ¹ may form a ring).

Specific examples of the four amine groups R ¹ having the same amine-based ionic liquid include, for example, N, N, N, N-tetrabutylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetra Pentylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetrahexylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetraheptylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetraoctylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetranonylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetradecylammonium bis (trifluoro) Lomethanesulfoni ) Imide, N, N, N, N-tetradodecylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N-tetrahexadecylammonium bis (trifluoromethanesulfonyl) imide, N, N, N, N- And tetraoctadecyl ammonium bis (trifluoromethanesulfonyl) imide.

Specific examples of the amine-based ionic liquid in which the three alkyl groups R ¹ are the same include, for example, N, N, N-trimethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl- N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl-N-hexylammonium bis (trifluoromethanesulfonyl) Imido, N, N, N-trimethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl-N-octylammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl- N-nonylua Examples include ammonium bis (trifluoromethanesulfonyl) imide, N, N, N-trimethyl-N-decylammonium bis (trifluoromethanesulfonyl) imide, and the like.

In the present invention, the amine-based ionic liquid, among the above, CF 3 _SO 3 as anion _- is preferably a ^{(trifluoromethanesulfonyl} ion), also four of the alkyl R ¹ all having 3 or less carbon atoms A group is preferred.

  The hydroxyl group-containing ionic liquid has two hydroxyl groups, and preferably has two hydroxyl groups at the ends. Such an ionic liquid having two hydroxyl groups is not particularly limited. For example, an amine-based ionic liquid having two hydroxyl groups having an ammonium ion having two hydroxyl groups as a cation, and an imidazolium ion having two hydroxyl groups. Examples include imidazolium-based ionic liquids having two hydroxyl groups as cations, and pyridinium-based ionic liquids having two hydroxyl groups having pyridinium ions having two hydroxyl groups as cations. The hydroxyl group-containing ionic liquid contained in the urethane resin composition may be one kind or plural. The anion in the hydroxyl group-containing ionic liquid is basically the same as the anion. Among hydroxyl group-containing ionic liquids, amine-based ionic liquids having two hydroxyl groups, particularly aliphatic amine-based ionic liquids having two hydroxyl groups, can substantially suppress the occurrence of fogging in a low humidity environment. In addition, even if the standby or stop of the image forming apparatus continues for a long period of time, it is preferable in that it is possible to substantially suppress the occurrence of white streaks in the image formed thereafter.

  The aliphatic amine-based ionic liquid having two hydroxyl groups is a fatty acid having a basic skeleton of ammonium ions having two hydroxyl groups formed by bonding four substituents to nitrogen atoms of an aliphatic amine compound as cations. It is an amine-based ionic liquid of the group. Examples of the aliphatic amine compound include alicyclic amine compounds and aliphatic amine compounds.

As the ammonium ion, for example, two of (R ¹¹ R ¹² R ¹³ R ¹⁴ ) N ⁺ ion (R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different, each having one hydroxyl group. A linear, branched or cyclic aliphatic organic group having 1 to 20 carbon atoms, the remaining two of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different, It is a linear, branched or cyclic alkyl group or alkenyl group having a number of 1 to 20, and two of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may form a ring. Can be mentioned.

The two aliphatic organic groups of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are preferably linear aliphatic organic groups, and may have a substituent other than a hydroxyl group. Examples of the aliphatic organic group include an alkyl group having one hydroxyl group, an alkenyl group having one hydroxyl group, and a polyoxyalkylene group. The alkyl group and the alkenyl group preferably have 1 to 40 carbon atoms, and the polyoxyalkylene group preferably has 4 to 16 carbon atoms, for example, in the case of polyoxyethylene, the degree of polymerization is 2 to 8. . Examples of such organic groups include hydroxyalkyl groups such as hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, and hydroxyhexyl group, hydroxyalkenyl groups such as hydroxyethenyl group, hydroxypropenyl group, and the like. Examples thereof include polyoxyalkylene groups such as oxyethylene group and polyoxypropylene group. In this invention, it is preferable that two of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are the same aliphatic organic group.

The remaining two of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ other than the aliphatic organic group are linear, branched or cyclic alkyl groups or alkenyl groups having 1 to 40 carbon atoms. It is preferably a chain alkyl group or alkenyl group. The alkyl group or the alkenyl group may have a substituent. As such an alkyl group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, pentyl group, neopentyl group, hexyl group, Examples include isohexyl group, octyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, cyclopentyl group, cyclohexyl group and the like. Examples of the alkenyl group include ethenyl group, propenyl group, butenyl group, oleyl group and the like.

  Examples of the aliphatic amine ionic liquid having two hydroxyl groups include an aliphatic amine ionic liquid having two 2-hydroxyethyl groups and an aliphatic amine ionic liquid having two polyoxyethylene groups. . Specific examples of the aliphatic amine ionic liquid having two 2-hydroxyethyl groups include bis (2-hydroxyethyl) -methyl-octylammonium bis (trifluoromethanesulfonyl) imide and bis (2-hydroxy). Ethyl) -methyl-decylammonium bis (trifluoromethanesulfonyl) imide, bis (2-hydroxyethyl) -methyl-dodecylammonium bis (trifluoromethanesulfonyl) imide, bis (2-hydroxyethyl) -methyl-tetradecylammonium bis ( Trifluoromethanesulfonyl) imide, bis (2-hydroxyethyl) -methyl-hexadecylammonium bis (trifluoromethanesulfonyl) imide, bis (2-hydroxyethyl) -methyl-octadecylan Monium bis (trifluoromethanesulfonyl) imide, ethyl-bis (2-hydroxyethyl) -octylammonium bis (trifluoromethanesulfonyl) imide, ethyl-bis (2-hydroxyethyl) -decylammonium bis (trifluoromethanesulfonyl) imide, ethyl -Bis (2-hydroxyethyl) -dodecylammonium bis (trifluoromethanesulfonyl) imide, ethyl-bis (2-hydroxyethyl) -tetradecylammonium bis (trifluoromethanesulfonyl) imide, ethyl-bis (2-hydroxyethyl)- Hexadecylammonium bis (trifluoromethanesulfonyl) imide, ethyl-bis (2-hydroxyethyl) -octadecylammonium bis (trifluoromethanes Honiru) imide, Oreirubisu (2-hydroxyethyl) methyl ammonium bis (trifluoromethanesulfonyl) imide, oleyl - ethyl - bis (2-hydroxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, and the like.

  Specific examples of the aliphatic amine-based ionic liquid having two polyoxyethylene groups include bis (polyoxyethylene) -methyl-octylammonium bis (trifluoromethanesulfonyl) imide and bis (polyoxyethylene)- Methyl-decylammonium bis (trifluoromethanesulfonyl) imide, bis (polyoxyethylene) -methyl-dodecylammonium bis (trifluoromethanesulfonyl) imide, bis (polyoxyethylene) -methyl-tetradecylammonium bis (trifluoromethanesulfonyl) imide Bis (polyoxyethylene) -methyl-hexadecylammonium bis (trifluoromethanesulfonyl) imide, bis (polyoxyethylene) -methyl-octadecylammonium bis Trifluoromethanesulfonyl) imide, oleyl - bis (polyoxyethylene) - methylammonium bis (trifluoromethanesulfonyl) imide, and the like.

  The ionic liquid is preferably at least one selected from pyridinium ionic liquids if it is particularly important to suppress the occurrence of fogging in a low humidity environment. On the other hand, the ionic liquid is the hydroxyl group-containing ionic liquid, particularly an amine-based ionic liquid having two hydroxyl groups, if it is particularly important to suppress the occurrence of white streaks in the image together with the occurrence of the fog. Is preferred.

  The urethane resin contained in the urethane coat layer 4 may be a known urethane resin when the ionic liquid contains a hydroxyl group and is not an ionic liquid, and is usually obtained from a polyol and a polyisocyanate. The polyol is preferably a polyester polyol or a polyether polyol. Examples of the polyisocyanate include aliphatic polyisocyanates and aromatic polyisocyanates. Details will be described in the urethane resin composition.

On the other hand, when the ionic liquid is a hydroxyl group-containing ionic liquid, the urethane resin contained in the urethane coat layer 4 is a reaction product of the ionic liquid, the polyol, and the polyisocyanate, and its main chain. Alternatively, the ionic liquid, specifically, the cation portion thereof is bonded to the side chain. If the anion of the hydroxyl group-containing ionic liquid is present in the urethane coat layer 4, it binds to the cation by electrostatic action or exists in the vicinity of the cation, and part of the urethane resin. It may be, may exist away from the cation, may be independent of the urethane resin, or both. Such a urethane resin is composed of repeating units (I) to (III). That is, this urethane resin contains repeating units (I) to (III).
(I) -O-A-O-
(II) R _ol (—O—) _n
(III) R _is (-NHCO-) _m

In the repeating units (I) to (III), the repeating unit (I) is a residue of the hydroxyl group-containing ionic liquid and may or may not contain the anion, and the A contains the hydroxyl group. It is a residue excluding the hydroxyl group of the ionic liquid. The repeating unit (II) is a residue of the polyol, the _Rol is a residue excluding the hydroxyl group of the polyol, n is an integer of 2 or more, and n or more of the (—O—) are independent of each other. _Are bound to _Rol . A residue of the repeating unit (III) is the polyisocyanate, wherein R _IS is a residue excluding isocyanate group of the polyisocyanate, m is an integer of 2 or more, m or more of the (-NHCO- ) is attached to said R _iS independently.

  The repeating units (I) to (III) are derived from the hydroxyl group-containing ionic liquid, the polyol and the polyisocyanate, respectively, and are basically the same as these. Therefore, for example, the repeating unit (I) is preferably a residue of an aliphatic amine ionic liquid having two hydroxyl groups, and the repeating unit (II) is a residue of a polyester diol or a polyether diol. The repeating unit (III) is preferably a residue of an aliphatic diisocyanate or a residue of an aromatic polyisocyanate. The polyol and the polyisocyanate are basically the same as the polyol and the polyisocyanate forming the urethane resin in an ionic liquid not containing a hydroxyl group, and the details thereof will be described in the urethane resin composition.

  The urethane resin is such that the mass of the repeating unit (I) is 1 to 20 parts by mass when the total mass of the mass of the repeating unit (II) and the mass of the repeating unit (III) is 100 parts by mass. It has repeating units (I) to (III). Here, the mass of the repeating unit (I) is a mass when converted into the hydroxyl group-containing ionic liquid (including an anion) before the reaction, and the mass of the repeating unit (II) is the polyol before the reaction. The mass of the repeating unit (III) is the mass when converted to the polyisocyanate before the reaction. Usually, the content of each repeating unit (I) to (III) in this urethane resin substantially coincides with the content of the urethane resin adjusting component and ionic liquid contained in the urethane resin composition forming the urethane coat layer 4.

  The urethane coat layer 4 contains the ionic liquid in a ratio of 1 to 20 parts by mass with respect to 100 parts by mass of the urethane resin. If the content of the ionic liquid is less than 1 part by mass, the effect of the ionic liquid may not be sufficiently obtained, and the occurrence of fogging in a low humidity environment may not be suppressed. On the other hand, when the content of the ionic liquid exceeds 20 parts by mass, the charged developer may be discharged and the developer cannot be supported on the surface of the developing roller. As a result, fogging is likely to occur in a low humidity environment, and density unevenness is likely to occur in the halftone image, which may degrade the quality of the formed image. When the ionic liquid is the hydroxyl group-containing ionic liquid, if the content exceeds 20 parts by mass, white streaks may occur in the image formed after the standby of the image forming apparatus, and the image quality may be deteriorated. . In the present invention, the occurrence of fogging in a low humidity environment can be substantially suppressed, and if desired, even if the image forming apparatus is kept on standby or stopped for a long period of time, white stripes are formed in an image formed thereafter. It is preferable that the content of the ionic liquid is 9 to 19 parts by mass with respect to 100 parts by mass of the urethane resin in that generation can be effectively suppressed. Usually, the content of the ionic liquid in the urethane coat layer 4 substantially matches the content of the ionic liquid with respect to 100 parts by mass of the urethane resin adjusting component contained in the urethane resin composition forming the urethane coat layer 4.

The fluorine-containing surfactant contained in the urethane coat layer 4 is preferably a compound having a perfluoroalkyl group (—C _n F _{2n + 1} ) in the molecule, and the perfluoroalkyl group has 1 to 6 carbon atoms. Of these, a perfluoroalkyl group is preferable, and a perfluorobutyl group, a perfluorohexyl group, and the like are particularly preferable. Thus, when the urethane coat layer 4 of the conductive roller 1 contains a predetermined amount of the fluorosurfactant, even if the ionic liquid is contained, the characteristics of the urethane coat layer 4 with respect to the developer, for example, contact Corners and / or surface energy can be improved, and the object of the present invention can be achieved well.

  As the fluorosurfactant, in particular, a low molecular weight compound fluorosurfactant and an oligomeric fluorosurfactant can improve the contact angle and / or surface energy. preferable. Examples of the low molecular weight compound fluorine-based surfactant include various acids having perfluoroalkyl groups in the molecule or salts thereof, and specifically, for example, perfluorobutyl sulfonate, perfluoro Examples thereof include alkyl group-containing carboxylates, perfluoroalkyl group-containing phosphate esters, perfluoroalkyl group-containing phosphate ester type compounds, and ethylene oxide adducts. Examples of the perfluorobutyl sulfonate include a trade name “Megafac” (product number F-114), and examples of the perfluoroalkyl group-containing carboxylate include a product name “megafuck” (product number F-410). As a fluoroalkyl group-containing phosphate ester, for example, trade name “Megafac” (product number F-493), and as the perfluoroalkyl group-containing phosphate ester type compound, for example, product name “Megafuck” (product number F-494). As the ethylene oxide adduct, for example, a product name “megafuck” (product number F-443), a product name “megafuck” (product number F-444), a product called a perfluoroalkylethylene oxide adduct, Name “Mega Fuck” (Part No. F-445) and Product Name “Mega Fuck” (Part No. F-44) ) (Above, manufactured by Dainippon Ink and Chemicals) and the like.

  As the oligomeric fluorosurfactant, the main chain is a perfluoroalkyl group, and the molecular weight is preferably from 500 to 10,000, more preferably from 600 to 9000, particularly preferably from 700 to 8000, in terms of polystyrene by GPC. Examples of such oligomeric fluorosurfactants include oligomers containing perfluoroalkyl groups, hydrophilic groups, and lipophilic groups. More specifically, the oligomeric fluorosurfactant includes, for example, a perfluoroalkyl group / hydrophilic group / lipophilic group-containing oligomer (trade names “Megafac” (Part Nos. F-470, F-471, F -475, F-477, F-479, R-08, R-30 and R-110), etc., perfluoroalkyl group / hydrophilic group-containing oligomer (trade name “Megafac” (Part No. F-480SF), Par Fluoroalkyl group / lipophilic group-containing oligomers (trade names “Megafac” (Part Nos. F-482, F-483, F-489) (above, manufactured by Dainippon Ink and Chemicals, Inc.), etc.) For example, a surfactant containing a perfluorobutane sulfonic acid group may be used, and as such a surfactant, for example, a trade name “Novec FC-44” may be mentioned. 0 "and" Novec FC-4432 "(Sumitomo 3M Limited), and the like.

  The ionicity of the fluorosurfactant is not particularly limited, but is preferably nonionic because it does not affect the dispersibility of the carbon black for conductivity adjustment.

  Content of a fluorochemical surfactant is 0.1-5 mass parts with respect to 100 mass parts of urethane resins. When the content of the fluorosurfactant is less than 0.1 parts by mass, the effect of containing the fluorosurfactant cannot be sufficiently obtained, and the object of the present invention cannot be sufficiently achieved. is there. On the other hand, even if the content of the fluorosurfactant exceeds 5 parts by mass, the object of the present invention can be sufficiently achieved, but the effect of containing the fluorosurfactant does not increase so much, so From the viewpoint of reducing the amount of the activator used, the amount is preferably 5 parts by mass. The content of the fluorosurfactant is 0.1 to 2 parts by mass with respect to 100 parts by mass of the urethane resin because the object of the present invention and the amount of the fluorosurfactant used can be sufficiently reduced. Is preferable, and it is especially preferable that it is 0.1-0.7 mass part. The content of the fluorosurfactant can be measured by analyzing the urethane coat layer 4 with a photoelectron spectrometer (ESCA). Usually, the content of the fluorosurfactant in the urethane coat layer 4 is almost the same as the content of the fluorosurfactant with respect to 100 parts by mass of the urethane resin adjusting component contained in the urethane resin composition forming the urethane coat layer 4. Match.

  When the urethane coat layer 4 contains carbon black, the DBP adsorption amount of the carbon black is preferably less than 100 mL / 100 g. The DBP adsorption amount can be measured according to JIS K6217-4. The urethane coat layer 4 does not substantially contain resin particles as in Patent Document 5.

  The urethane coat layer 4 having the above composition preferably has a contact angle larger than the contact angle of the developer that contacts or carries the surface. When the urethane coat layer 4 has such a large contact angle, even if the developer melts due to operation of the image forming apparatus, the developer hardly adheres to the urethane coat layer 4 and adheres to the urethane coat layer 4. The amount can be significantly reduced.

  The urethane coat layer 4 preferably has a hexadecane contact angle of 45 to 75 °, more preferably 45 to 70 °, and particularly preferably 50 to 70 °. The contact angle can be measured using, for example, a contact angle meter (trade name “CA-DT type”, manufactured by Kyowa Interface Chemical Co., Ltd.). A sample of the urethane coat layer 4 where the developer contact area is cut out to 10 mm × 10 mm is set on a contact angle meter, and a hexadecane droplet is dropped as a test solution on the sample so that the droplet diameter is 2 mm. . The contact angle is measured by reading the angle formed between the contact point of the sample and the droplet and the top of the droplet with an angle scale built in the contact angle meter and converting it to double.

  The urethane coat layer 4 preferably has a surface energy of 14 to 17 mN / m. The surface energy can be obtained by a dysman plot using a contact angle meter (model “CA-A type, manufactured by Kyowa Interface Science Co., Ltd.) Specifically, the contact angle using hexadecane and diiodomethane as measurement solvents. The surface tension and the contact angle θ in each measurement solvent of the urethane coat layer 4 are measured with a meter, the measured surface tension value is plotted on the horizontal axis, and the cos θ value calculated from the measured contact angle θ is plotted on the vertical axis. As the surface energy of the urethane coat layer 4, the value of the intersection of the extended line of the straight line connecting the two plots plotted on the XY coordinates and the straight line of X (cos θ) = 1.0.

  When the contact angle and the surface energy are within the above ranges, the developer melted by the operation of the image forming apparatus hardly adheres to the urethane coat layer 4, and the amount of developer fixed to the urethane coat layer 4 is remarkably reduced. it can.

  The urethane resin composition that forms the urethane coat layer 4 includes a urethane adjusting component that is a precursor that forms the urethane resin, and a predetermined amount, that is, 1 to 20 parts by mass of an ionic liquid with respect to 100 parts by mass of the urethane adjusting component. And a predetermined amount, that is, 0.1 to 5 parts by mass of a fluorosurfactant with respect to 100 parts by mass of the urethane adjusting component, and optionally various additives. Therefore, the urethane coat layer 4 is formed by applying a urethane resin composition containing a urethane adjusting component, a predetermined amount of ionic liquid, a predetermined amount of a fluorosurfactant, and optionally various additives, to the outer peripheral surface of the elastic layer 3. It is formed by coating and curing. The ionic liquid, fluorine-based surfactant and various additives in the urethane resin composition are as described above.

  The urethane adjusting component may be any component that can form polyurethane, and examples thereof include a mixture of a polyol and an isocyanate.

  The polyol may be any of various polyols usually used in the preparation of polyurethane having at least two hydroxyl groups in the molecule and other than the ionic liquid when the ionic liquid is a hydroxyl group-containing ionic liquid. Any polyol may be used as long as it is a polyol and is usually used for preparing polyurethane. Such a polyol is preferably at least one polyol selected from polyether polyols and polyester polyols. When the ionic liquid is a hydroxyl group-containing ionic liquid, the polyol is preferably a diol, and more preferably a polyester diol or a polyether diol, and particularly preferably a polyester diol.

  Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polypropylene glycol-ethylene glycol, polytetramethylene ether glycol, copolymer polyols of tetrahydrofuran and alkylene oxide, and various modified products thereof. These mixtures etc. are mentioned. Examples of the polyester polyol include condensed polyester polyols obtained by condensation of dicarboxylic acids such as adipic acid and polyols such as ethylene glycol and hexanediol, lactone polyester polyols, polycarbonate polyols, and mixtures thereof. Can be mentioned. The polyether polyol and polyester polyol may be used singly or in combination of two or more, or a polyether polyol and a polyester polyol may be used in combination. The polyol is preferably a polyester polyol because it is excellent in thermal stability. The polyol preferably has a number average molecular weight of 1000 to 8000, more preferably a number average molecular weight of 1000 to 5000, and the ionic liquid contains a hydroxyl group in terms of excellent compatibility with polyisocyanate and the like described later. When it is an ionic liquid, it preferably has a number average molecular weight of 800-15000, more preferably 1000-5000. The number average molecular weight is a molecular weight when converted to standard polystyrene by gel permeation chromatography (GPC).

  The polyisocyanate may be any of various polyisocyanates usually used in the preparation of polyurethane having at least two isocyanate groups in the molecule, and examples thereof include aliphatic polyisocyanates, aromatic polyisocyanates and these polyisocyanates. Derivatives and the like. The polyisocyanate is preferably an aliphatic polyisocyanate from the viewpoint of excellent storage stability and easy control of the reaction rate. In the case where the ionic liquid is the hydroxyl group-containing ionic liquid, the polyisocyanate is preferably a diisocyanate. Further, the polyisocyanate is high even in a low humidity environment even after the image forming apparatus has been on standby or stopped for a long time. Aliphatic polyisocyanates are preferred and, therefore, aliphatic diisocyanates are particularly preferred in that a quality image can be formed.

  Examples of the aromatic polyisocyanate include xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (also referred to as tolylene diisocyanate, TDI), 3,3′-bitolylene-4,4′-diisocyanate, 3 , 3′-dimethyldiphenylmethane-4,4′-diisocyanate, 2,4-tolylene diisocyanate uretidinedione (a dimer of 2,4-TDI), xylene diisocyanate, naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PDI) ), Tolidine diisocyanate (TODI), metaphenylene diisocyanate and the like. Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), orthotoluidine diisocyanate, lysine diisocyanate methyl ester, isophorone diisocyanate (IPDI), norbornane diisocyanate methyl, trans Examples include cyclohexane-1,4-diisocyanate and triphenylmethane-4,4 ′, 4 ″ -triisocyanate. Examples of the derivatives include polynuclear polyisocyanates, urethane-modified products modified with polyols (including urethane prepolymers), dimers formed by uretidione formation, isocyanurate-modified products, carbodiimide-modified products, uretonimine-modified products, and allophanate-modified products. Products, urea-modified products, and burette-modified products. The said polyisocyanate can be used individually by 1 type or 2 or more types. The polyisocyanate preferably has a molecular weight of 500 to 2000, more preferably 700 to 1500.

  The mixing ratio of the polyol and the hydroxyl group-containing ionic liquid and the polyisocyanate is not particularly limited, but the hydroxyl group (OH) contained in the polyol and the hydroxyl group (OH) contained in the hydroxyl group-containing ionic liquid are not particularly limited. It is preferable that the ratio [NCO / OH] of the total number of moles and the number of moles of isocyanate groups (NCO) contained in the polyisocyanate is 0.7 to 1.15. This ratio [NCO / OH] is more preferably 0.85 to 1.10 in that the hydrolysis of the polyurethane can be prevented. However, in practice, an amount corresponding to 3 to 4 times the appropriate molar ratio may be blended in consideration of work environment and work errors.

  The ionic liquid in the urethane resin composition is 1 to 20 parts by mass when the total content of the polyol and the polyisocyanate is 100 parts by mass. When the content of the ionic liquid is less than 1 part by mass, the effect of the ionic liquid may not be sufficiently obtained as described above. On the other hand, when the content exceeds 20 parts by mass, as described above. The quality of the formed image may deteriorate. It is possible to effectively suppress the occurrence of fogging in a low-humidity environment, and it is effective that white streaks occur in an image formed afterwards even if the standby or stop of the image forming apparatus continues for a long period of time. The content of the ionic liquid is preferably 9 to 19 parts by mass when the total content of the polyol and the polyisocyanate is 100 parts by mass.

  In addition to the polyol and polyisocyanate, the urethane resin composition may be used in combination with an auxiliary agent usually used for the reaction between the polyol and polyisocyanate, such as a chain extender and a crosslinking agent. Examples of chain extenders and crosslinking agents include glycols, hexanetriol, trimethylolpropane, and amines.

  The urethane resin composition is obtained by mixing the ionic liquid, the polyol, the polyisocyanate, and, if desired, a solvent, an auxiliary agent, and the like by an appropriate method.

  A method for manufacturing the conductive roller 1 will be described below. The conductive roller 1 is manufactured by forming the elastic layer 3 on the outer peripheral surface of the shaft body 2 and further forming the urethane coat layer 4 on the outer peripheral surface of the elastic layer 3. In order to manufacture the conductive roller 1, first, the shaft body 2 is prepared. For example, the shaft body 2 is prepared in a desired shape by a known method. The shaft body 2 may be coated with a primer before the elastic layer 3 is formed. Although there is no restriction | limiting in particular as a primer apply | coated to the shaft body 2, Resin and the crosslinking agent similar to the material which forms the primer layer which adheres or adheres the said elastic layer 3 and the urethane coat layer 4 are mentioned. The primer is dissolved in a solvent or the like as desired, and is applied to the outer peripheral surface of the shaft body according to a conventional method such as a dipping method or a spray method.

  The elastic layer 3 is formed by heat-curing the conductive composition on the outer peripheral surface of the shaft body 2. For example, the elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by performing heat curing and molding simultaneously or continuously by a known molding method. The method for curing the conductive composition may be any method that can apply heat necessary for curing the conductive composition, and the method for forming the elastic layer 3 may be continuous vulcanization by extrusion, pressing, molding by injection, etc. There is no particular limitation. For example, when the conductive composition is an addition curable millable conductive silicone rubber composition, for example, extrusion molding or the like can be selected, and the conductive composition is an addition curable liquid conductive silicone rubber composition. In this case, for example, a molding method using a mold can be selected. The heating temperature for curing the conductive composition is 100 to 500 ° C., particularly 120 to 300 ° C., in the case of an addition-curable millable conductive silicone rubber composition, and the time is several seconds to 1 hour, particularly 10 seconds or more. ~ 35 minutes or less is preferable, and in the case of an addition-curable liquid conductive silicone rubber composition, it is 100 to 300 ° C, particularly 110 to 200 ° C, and the time is 5 minutes to 5 hours, particularly 1 to 3 hours. Is preferred. In addition, in the case of an addition-curable millable conductive silicone rubber composition, if necessary, the curing conditions are about 100 to 200 ° C. for about 1 to 20 hours, and in the case of an addition-curable liquid conductive silicone rubber composition. Secondary vulcanization may be performed at 120 to 250 ° C. under curing conditions for about 2 to 70 hours. In addition, the conductive composition can be foamed and cured by a known method to easily form a sponge-like elastic layer having bubbles.

  The elastic layer 3 formed in this way has its surface polished and ground as desired to adjust the outer diameter, surface state, and the like. Further, the primer layer may be formed on the elastic layer 3 formed in this way before the urethane coat layer 4 is formed.

  The urethane coat layer 4 is formed by coating the urethane resin composition on the outer peripheral surface of the elastic layer 3 thus formed or the primer layer formed as desired, and then applying the urethane resin composition. An object is formed by heat curing or moisture curing. The application of the urethane resin composition includes, for example, a coating method in which a coating liquid of the urethane resin composition is applied, a dipping method in which the elastic layer 3 or the like is immersed in the coating liquid, and the coating liquid in the elastic layer 3 or the like. It is carried out by a known coating method such as a spray coating method for spraying on the surface. The urethane resin composition may be applied as it is, or applied to the urethane resin composition, for example, alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, and ester solvents such as ethyl acetate and butyl acetate. You may apply the coating liquid which added volatile solvents, such as these, or water. The urethane resin composition thus coated may be cured by any method that can add heat or moisture necessary for curing the urethane resin composition. For example, the urethane resin composition is coated. And a method of heating the elastic layer 3 and the like with a heater, a method of leaving the elastic layer 3 and the like coated with the urethane resin composition under high humidity, and the like. The heating temperature when the urethane resin composition is heat-cured is, for example, 100 to 200 ° C., particularly 120 to 160 ° C., and the heating time is preferably 10 to 120 minutes, particularly preferably 30 to 60 minutes. In addition, instead of the coating, the urethane resin composition was laminated on the outer peripheral surface of the elastic layer 3 or the primer layer by a known molding method such as extrusion molding, press molding, injection molding, or the like. Later, a method of curing the laminated urethane resin composition or the like can be employed.

  The conductive roller 1 is selected from the group consisting of urethane resin and 1 to 20 parts by mass of pyridinium-based ionic liquid, amine-based ionic liquid, and ionic liquid having two hydroxyl groups with respect to 100 parts by mass of the urethane resin. Since the developer comprises the urethane coat layer 4 containing at least one ionic liquid and 0.1 to 5 parts by mass of a fluorosurfactant with respect to 100 parts by mass of the urethane resin, the developer is melted. However, it hardly adheres to the urethane coat layer 4, and as a result, the developer does not substantially adhere to the surface even when the image forming apparatus is operated for a long period of time. As described above, the conductive roller 1 is difficult for the developer to adhere to the surface for a long period of time. Therefore, a predetermined amount of developer is applied to the image carrier for a long period of time without impairing the effect of the ionic liquid described later. To maintain the image quality, and further, the developer is not leaked from the developing device. Therefore, the conductive roller according to the present invention can contribute to maintenance of image quality over a long period of time and prevention of developer leakage when mounted on the developing device and / or the image forming apparatus. That is, the conductive roller according to the present invention does not leak the developer without deteriorating the developer carrying and conveying function over a long period of time even if it contains an ionic liquid for the purpose of image formation without fogging. .

  In addition, since the conductive roller 1 includes the urethane coat layer 4, the occurrence of fogging can be substantially suppressed not only in a normal humidity but also in a low humidity environment with a relative humidity of 10%, for example. The conductive roller 1 has such an excellent effect because the urethane coat layer 4 is used as the surface layer even when the developer supplied to the image carrier is excessively charged in a low humidity environment. If the conductive roller 1 is used as a developing roller, the conductive roller 1 effectively neutralizes the excessive charge amount charged in the developer, and the charge amount of the developer supplied to the image carrier is changed to a normal humidity environment. The inventors of the present application speculate that the charge amount may be almost the same as the lower charge amount.

  Furthermore, the conductive roller 1 can substantially suppress the occurrence of fog even when the surrounding humidity changes from, for example, normal humidity to low humidity. Therefore, according to the present invention, it is possible to achieve the object of providing a conductive roller and an image forming apparatus that can form an image without fogging even when the surrounding humidity changes to low humidity.

  Since the conductive roller 1 includes the urethane coat layer 4, the image forming apparatus is in a state where the conductive roller 1 mounted on the image forming apparatus is in contact with or pressed against a contacted body such as an image carrier. However, even if the image forming apparatus is activated or stopped thereafter for a long period of time, for example, for 5 days or more, it is possible to substantially prevent white streaks from occurring in an image formed after the image forming apparatus is operated. In particular, when the urethane coat layer 4 contains the hydroxyl group-containing ionic liquid, it is possible to highly prevent the occurrence of the white streaks in the image in addition to the prevention of the fog. The conductive roller 1 achieves such an excellent effect because the ionic liquid present in the urethane coat layer 4 can move inside the urethane coat layer 4 even if the standby or stop of the image forming apparatus continues for a long period of time. It is difficult to move, and it is difficult to shift to the contacted body with which the conductive roller 1 contacts, so that the uniformity of the urethane coat layer 4 is not impaired and the contacted body is not contaminated. The present inventors have speculated.

  As described above, when the conductive roller 1 is mounted on the image forming apparatus as a conductive roller such as a developing roller, for example, even after the image forming apparatus has been on standby or stopped for a long period of time, or in a low humidity environment. The image forming apparatus can contribute to forming a high-quality image. Further, since the conductive roller 1 can substantially suppress the occurrence of fog even when the surrounding humidity changes from, for example, normal humidity to low humidity, according to the present invention, the image forming apparatus can be used for a long time. The object of providing an electroconductive roller and an image forming apparatus capable of forming an image without fogging even after waiting or stopping for a long time and even when the surrounding humidity changes to low humidity can be achieved. Furthermore, even if the conductive roller 1 contains 1 to 20 parts by mass of an ionic liquid in the urethane resin composition, and particularly contains 5 parts by mass or more, the conductive roller 1 cures the urethane resin composition. It is difficult for the ionic liquid to bleed out from the urethane coat layer 4 formed. As a result, it is possible to contribute to forming a high-quality image without contaminating the contacted body with which the conductive roller 1 is in contact.

  As described above, the conductive roller 1 can substantially suppress the occurrence of fog even when the surrounding area is low in humidity, and also substantially eliminates the occurrence of white streaks even after the image forming apparatus is on standby or stopped for a long time. In addition, the developer can be prevented from sticking. For example, the developer charged to a desired charge amount is carried on the surface of the developer to a uniform thickness and supplied to the image carrier. The developing roller and developer supply roller that are preferably used as a developing roller and a developer supply roller that need to exhibit the functions and functions described above, and that are mounted in contact with or pressed against a contacted body such as an image carrier. It is suitably used as a roller.

  Since the conductive roller according to the present invention has the above characteristics, the developer having a contact angle smaller than its own contact angle, for example, a developer having a contact angle of hexadecane of 35 to 40 ° is accommodated in the developing device. Particularly preferably used. Such a developer will be described later.

  Next, an example of a developing device (hereinafter, also referred to as a developing device according to the present invention) including the conductive roller 1 according to the present invention, and an image forming apparatus (hereinafter referred to as a developing device of this example) An example of the image forming apparatus according to the present invention will be described with reference to FIG.

  As shown in FIG. 2, the image forming apparatus 10 includes developing devices 20B, 20C, 20M, and 20Y according to the present invention. In the developing devices 20B, 20C, 20M and 20Y and the image forming apparatus 10, the conductive roller 1 is mounted as a developer carrier 23B, 23C, 23M and 23Y, that is, as a developing roller. As shown in FIG. 2, the image forming apparatus 10 includes a plurality of image carriers 11B, 11C, 11M, and 11Y that are mounted on the developing units B, C, M, and Y of each color in series on a transfer conveyance belt 6. Therefore, the developing units B, C, M, and Y are arranged in series on the transfer conveyance belt 6 wound around the two support rollers 42. The developing unit B includes an image carrier 11B such as a photosensitive member (also referred to as a photosensitive drum), a charging unit 12B such as a charging roller, an exposure unit 13B, a developing device 20B, and an image carrying belt 6. A transfer unit 14B that contacts the body 11B, such as a transfer roller, and a cleaning unit 15B are provided. The developing units C, M, and Y are basically configured in the same manner as the developing device B.

  The developing device 20B adjusts the thickness of a casing 21B that accommodates a one-component non-magnetic developer 22B, a developer carrier 23B that supplies the developer 22B to the image carrier 11B, such as a developing roller, and the thickness of the developer 22B. Developer amount adjusting means 24B, for example, a blade. The developing device 20B is mounted on the image forming apparatus 10 such that the conductive roller 1 as the developer carrier 23B is in contact with or pressure contact with the image carrier 11B. The nip width between the conductive roller 1 and the image carrier 11B at this time is normally adjusted so that the circumferential length of the conductive roller 1 is 0.1 to 2 mm. The developing devices 20C, 20M, and 20Y are basically configured similarly to the developing device 20B.

  The developers 22B, 22C, 22M, and 22Y used in the image forming apparatus 10 are all developers that can be charged by friction, and the contact angle thereof is larger than the contact angle of the urethane coat layer 4 of the conductive roller 1. The contact angle with respect to hexadecane is preferably 35 to 40 °, and particularly preferably 36 to 40 °. Therefore, the developers 22B, 22C, 22M, and 22Y may be such a developer, and may be, for example, a dry developer or a wet developer, and may be a non-magnetic developer or a magnetic developer. Within the housings 21B, 21C, 21M and 21Y of each developing unit, the one-component non-magnetic black developer 22B, cyan developer 22C, magenta developer 22M and yellow having the contact angle of 35 to 40 °. Developer 22Y is stored. Examples of such a developer include a developer for a printer (trade name “HL-4040CN”, manufactured by Brother Industries, Ltd.). The contact angle of the developer is basically the same as the contact angle of the urethane coat layer 4 using a sample obtained by solidly printing 10 mm × 10 mm made of developer on plain paper instead of the sample cut out to 10 mm × 10 mm. It can be measured. Examples of such a developer include a developer for a printer (trade name “HL-4040CN”, manufactured by Brother Industries, Ltd.). When the contact angle of the developer hexadecane is within the above range, even if the developer is melted by the operation of the image forming apparatus, it hardly adheres to the urethane coat layer 4 and the amount of the developer fixed to the urethane coat layer 4 can be significantly reduced. . Here, the difference between the contact angle of the urethane coat layer 4 of the conductive roller 1 and the contact angle of the developer is preferably 10 to 25 °, for example. If the difference in the contact angle is within the above range, the object of the present invention can be well achieved.

  The fixing unit 30 is disposed downstream of the developing unit Y in the conveyance direction of the recording medium 16. The fixing unit 30 includes a fixing roller 31, an endless belt support roller 33 disposed in the vicinity of the fixing roller 31, a fixing roller 31, and an endless belt support roller in a housing having an opening 35 through which the recording medium 16 passes. 33, an endless belt 36 wound around 33, and a pressure roller 32 disposed opposite to the fixing roller 31. The fixing roller 31 and the pressure roller 32 are in contact with or pressed against each other via the endless belt 36. It is a pressure heat fixing device which is supported in a freely rotatable manner. At the bottom of the image forming apparatus 10, a cassette 41 that houses the recording body 16 is installed.

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

  Since the developing devices 20B, 20C, 20M, and 20Y include the conductive roller 1 and the developer, even when the developer melts, the developer hardly adheres to the urethane coat layer 4 of the conductive roller 1 and develop. Even if the apparatuses 20B, 20C, 20M and 20Y are operated for a long period of time, the developer does not substantially adhere to the surface. As described above, since the developing device and the image forming apparatus according to the present invention include the conductive roller according to the present invention, a predetermined amount of developer can be imaged over a long period of time without impairing the effect of the ionic liquid. The image quality can be maintained by supplying it to the carrier, and the developer is not leaked from the developing device. Therefore, when the developing device according to the present invention is mounted on the image forming apparatus, it can contribute to maintaining the image quality for a long period of time and preventing the leakage of the developer. As a result, the image forming apparatus has a high quality for a long period of time. Contributes to forming images. The image forming apparatus according to the present invention can form a high-quality image for a long period of time. In other words, the developing device and the image forming apparatus according to the present invention contaminate the recording medium because the developer is difficult to leak over a long period of time even when the conductive roller containing the ionic liquid is provided for the purpose of image formation without fogging. And a high-density image can be formed without deteriorating the developer carrying and conveying function.

  Since the tandem type image forming apparatus 10 is provided with the conductive roller 1 as the developer carrying member 23, the fog is substantially free even in a low humidity environment of 10% relative humidity as well as normal humidity. High quality images can be formed. In addition, when the conductive roller 1 is mounted as the developer carrying member 23, the uniformity of the urethane coat layer 4 of the conductive roller 1 is impaired even if the tandem type image forming apparatus 10 is on standby or stopped for a long period of time. In addition, the tandem image forming apparatus 10 can form a high-quality image having substantially no white streaks even if the standby or stop is continued for a long period of time without contaminating the image carrier 11.

  The image forming apparatus 10 is an image forming apparatus such as a copying machine, a facsimile machine, or a printer. Although the image forming apparatus 10 has been described with reference to the example in which the conductive roller 1 according to the present invention is used as a developing roller as an example of the developer carrier 23, the conductive roller 1 according to the present invention is used as a developer supply roller. Even if the property roller 1 is used, a high-quality image can be similarly formed.

  The conductive roller, the developing device, and the image forming apparatus according to the present invention are not limited to the above-described embodiments, and various modifications can be made as long as the object of the present invention can be achieved. For example, the conductive roller according to the present invention may have another layer between the elastic layer and the urethane coat layer. Examples of the other layer include a primer layer that adheres or adheres the elastic layer and the urethane coat layer. Examples of materials for forming the primer layer include alkyd resins, phenol-modified / silicone-modified alkyd resin modified products, oil-free alkyd resins, acrylic resins, silicone resins, epoxy resins, fluororesins, phenol resins, polyamide resins, urethanes. Examples thereof include resins and mixtures thereof. Moreover, as a crosslinking agent which hardens and / or bridge | crosslinks these resin, an isocyanate compound, a melamine compound, an epoxy compound, a peroxide, a phenol compound, a hydrogen siloxane compound etc. are mentioned, for example. The primer layer is formed with a thickness of 0.1 to 10 μm, for example.

  The image forming apparatus 10 is an electrophotographic image forming apparatus. However, in the present invention, the image forming apparatus is not limited to an electrophotographic system, and may be, for example, an electrostatic image forming apparatus. Good. Further, the image forming apparatus provided with the conductive roller according to the present invention is not limited to a tandem color image forming apparatus in which a plurality of image carriers having developing units of respective colors are arranged in series on a transfer conveyance belt. For example, a monochrome image forming apparatus provided with a single developing unit, a four-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier onto an endless belt may be used. The developer used in the image forming apparatus is a one-component non-magnetic developer. However, in the present invention, a one-component magnetic developer or a two-component non-magnetic developer may be used. Also, a two-component magnetic developer may be used. The fixing unit 30 may be a heat roller fixing device, a heat fixing device, a pressure fixing device, or the like.

(Example 1)
An electroless nickel-plated shaft body (SUM22, diameter 10 mm, length 275 mm) was washed with ethanol, and a silicone primer (trade name “Primer No. 16”, manufactured by Shin-Etsu Chemical Co., Ltd.) on its surface. ) Was applied. The shaft body subjected to the primer treatment 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 shaft body.

Next, 100 parts by mass of dimethylpolysiloxane (D) (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 (Nippon Aerosil Co., Ltd.) Made by company, R-972) 1 part by mass, average particle size 6 μm, bulk density of 0.25 g / cm ³ diatomaceous earth (F) (Oplite W-3005S, manufactured by Hokuaki Diatomite Co., Ltd.) 40 parts by mass, and 5 parts by mass of acetylene black (G) (Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was placed in a planetary mixer, stirred for 30 minutes, and then passed once through three rolls. This is returned to the planetary mixer again, and as a crosslinking agent, methyl hydrogen polysiloxane (E) having Si—H groups at both ends and side chains (polymerization degree 17, Si—H amount 0.0060 mol / g) 2. 1 part by mass, 0.1 part by mass of ethynylcyclohexanol as a reaction control agent and 0.1 part of platinum catalyst (H) (Pt concentration 1%) are added, and the mixture is stirred and kneaded for 15 minutes to be an addition curing type. A liquid conductive silicone rubber composition was prepared. The prepared addition-curable liquid conductive silicone rubber composition was molded on the outer peripheral surface of the shaft body 2 by liquid injection molding. In liquid injection molding, the addition-curable liquid conductive silicone rubber composition was cured by heating at 150 ° C. for 10 minutes. This molded body was polished to form an elastic layer 3 having an outer diameter of 20 mm.

  A urethane resin composition for forming the urethane coat layer 4 having the following composition was prepared. In the urethane resin composition, when the total content of the following polyol and polyisocyanate is 100 parts by mass, the content (parts by mass) of the ionic liquid, the fluorosurfactant and the carbon black is expressed as “equivalent content (parts by mass). ) "And shown in Table 1.

-Polyisocyanate (hexamethylene diisocyanate) 14 parts by mass-Condensed polyester polyol (mixing molar ratio of 1,6-hexanediol and adipic acid [COOH / OH] = 12/13, number average measured by the above measuring method The molecular weight was within the above range.) 28 parts by mass (molar ratio of polyisocyanate to condensed polyester polyol [NCO / OH] = 1.1 / 1)
- as pyridinium-based ionic liquid ^{_{"C 5 H 5 N + -C 6}} H 13 [(CF 3 SO 2) 2 N] - (N- hexyl pyridinium bis (trifluoromethanesulfonyl) imide) (manufactured by Kanto Chemical Co., Ltd.)" 1 part by mass-As a fluorosurfactant, "perfluorobutanesulfonic acid group-containing oligomer" (trade name "Novec FC-4432", manufactured by Sumitomo 3M Limited) 0.1 part by mass-dibutyltin dilaurate (trade name " Di-n-butyltin dilaurate ", manufactured by Showa Chemical Co., Ltd.) 0.03 parts by mass Silica (trade name“ ACEMATT OK-607 ”, manufactured by Degussa) 4 parts by mass Carbon black (trade name“ Toka Black # 4500 “Tokai Carbon Co., Ltd.) 3 parts by mass

  The urethane resin composition thus prepared was applied to the outer peripheral surface of the elastic layer 3 by a spray coating method and heated at 160 ° C. for 30 minutes to form a urethane coat layer 4 having a layer thickness of 22 μm. In this way, the conductive roller of Example 1 was manufactured.

(Examples 2 and 3)
Except that the content of the fluorosurfactant was changed to 0.2 parts by mass and 0.5 parts by mass, the conductive rollers of Examples 2 and 3 were respectively manufactured in the same manner as Example 1. did.

(Comparative Example 1)
A conductive roller of Comparative Example 1 was produced basically in the same manner as in Example 1 except that the pyridinium-based ionic liquid was not included.
(Comparative Example 2)
A conductive roller of Comparative Example 2 was produced basically in the same manner as in Example 1 except that the pyridinium ionic liquid was not contained and the content of the carbon black was changed to 6 parts by mass.

(Reference Example 1)
A conductive roller of Reference Example 1 was produced basically in the same manner as in Example 1 except that the fluorosurfactant was not included.

  Table 1 shows the values of the surface energy determined according to the above method as a result of measuring the contact angle with respect to the solvent “hexadecane” according to the above method using a sample cut out from the urethane coat layer of each conductive roller manufactured. The contact angle values shown in Table 1 are arithmetic average values when measured three times.

(Developer sticking evaluation 1)
Durability printing tests were performed using the respective conductive rollers manufactured in Examples 1 to 3, Comparative Examples 1 to 2, and Reference Example 1, and the amount of developer adhered was visually evaluated. The durability printing test was performed as follows. That is, using a printer (trade name “HL-4040CN”, manufactured by Brother Industries, Ltd.) equipped with each manufactured conductive roller as a developing roller, in a normal temperature and normal humidity environment (temperature 23 ° C., relative humidity 50%), A total of 2,000 black solids were printed on 5% of the total area of one side of A4 paper. Evaluation is “◎” when there is no developer fixed on the surface of the conductive roller after the endurance printing test, and “○” when the developer is slightly fixed to the extent that there is no practical problem. The case where the developer was fixed to an unacceptable level for practical use was designated as “x”. These evaluation results are shown in Table 1 as “sticking evaluation 1”. As the developer, black toner (black developer 22B, non-magnetic one-component developer) stored in the printer was used. The contact angle of the black toner with respect to the solvent “hexadecane” is 38.5 °, and the difference from the contact angle (hexadecane) of the urethane coat layer is shown in Table 1.

(Developer sticking evaluation 2)
Basically the same as “Developer sticking evaluation 1” except that magenta toner (magenta developer 22M, non-magnetic one-component developer) housed in the printer is used instead of the black toner. Thus, the fixing amount of the developer was evaluated. The contact angle of this magenta toner with respect to the solvent “hexadecane” is 39.6 °, and the difference from the contact angle (hexadecane) of the urethane coat layer is shown in Table 1.

  As shown in Table 1, it can be seen that if the sticking evaluations 1 and 2 of the developer are “◯” or more, the developer does not stick to the surface of the conductive roller over a long period even in the actual machine. It was. As described above, according to the present invention, a predetermined amount of developer can be supplied to the image carrier for a long period of time without impairing the effect of using the ionic liquid, and the image quality can be maintained. It was found that it would not leak.

DESCRIPTION OF SYMBOLS 1 Conductive roller 2 Shaft body 3 Elastic layer 4 Urethane coat layer 6 Transfer conveyance belt 10 Image forming apparatus 11B, 11C, 11M, 11Y Image carrier 12B, 12C, 12M, 12Y Charging means 13B, 13C, 13M, 13Y Exposure means 14B, 14C, 14M, 14Y Transfer means 15B, 15C, 15M, 15Y Cleaning means 16 23Y developer carrier 24B, 24C, 24M, 24Y developer regulating member 30 fixing means 31 fixing roller 32 pressure roller 33 endless belt support roller 35 opening 36 endless belt 41 cassette 42 support rollers B, C, M, Y development unit

Claims (6)

A conductive roller comprising an elastic layer formed on the outer peripheral surface of the shaft body and a urethane coat layer formed on the outer peripheral surface of the elastic layer,
The urethane coat layer is selected from the group consisting of a urethane resin and 1 to 20 parts by mass of a pyridinium ionic liquid, an amine ionic liquid, and an ionic liquid having two hydroxyl groups with respect to 100 parts by mass of the urethane resin. An electroconductive roller comprising at least one ionic liquid and 0.1 to 5 parts by mass of a fluorosurfactant with respect to 100 parts by mass of the urethane resin.   The conductive roller according to claim 1, wherein the urethane coat layer has a hexadecane contact angle of 45 to 75 °.   The conductive roller according to claim 1, wherein the urethane coat layer has a contact angle larger than a contact angle of a developer that contacts or carries the surface of the urethane coat layer.   A developing device comprising the conductive roller according to claim 1 and a developer.   The developing device according to claim 4, wherein the developer has a contact angle of hexadecane of 35 to 40 °.   An image forming apparatus comprising the developing device according to claim 4.

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