JP2012159807A - Conductive roller, developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive roller and a developing device designed to form high-quality images without fogging in a wide range of peripheral environment, as well as an image forming apparatus that forms high-quality images without fogging in a wide range of use environment.SOLUTION: Provided is a conductive roller 1 comprising an elastic layer 3 formed on an outer peripheral surface of a shaft body 2, and an urethane coat layer 4 formed on the outer peripheral surface of the elastic layer 3. The urethane coat layer 4 contains an urethane resin, at least one ionic liquid, the content of which is 1-25 parts by mass relative to 100 parts by mass of the urethane resin, and 1-25 parts by mass of a carboxylic acid metal compound relative to 100 parts by mass of the urethane resin. Also provided are a developing device comprising the conductive roller 1, and an image forming apparatus comprising the developing device.

Description

  The present invention relates to a conductive roller, a developing device, and an image forming apparatus. More specifically, the present invention relates to a conductive roller, a developing device, and a wide range that contribute to forming a high-quality image without fogging even if the surrounding environment is wide. The present invention relates to an image forming apparatus capable of forming a high-quality image without fogging even in various use environments.

  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) acrylate”. "Charging roll containing" (see Examples).

Further, Patent Document 2 is characterized in that “(A) to (C) are used as essential components, and a conductive composition for electrophotographic equipment is used for at least a part of a conductive member. 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” (implementation). See example).

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

By the way, Patent Document 6 states that, even when a plurality of images are output by the DC charging method, it is possible to suppress the occurrence of excessive charging due to the adhesion of the toner external additive. As a conductive member in which haze-like image defects do not occur on an image, the claim 1 has “at least a conductive support and a conductive elastic layer covering the conductive support. The electrically conductive member, wherein the surface layer of the electrically conductive member contains a compound composed of an aromatic carboxylic acid and a trivalent metal ". “A conductive member having at least a conductive support and a conductive elastic layer covering the conductive support, wherein the surface layer of the conductive member has an aromatic oxycarboxylic group. Aromatics selected from acids and aromatic alkoxycarboxylic acids A rubonic acid derivative, a metal compound of the aromatic carboxylic acid derivative, and an inorganic compound formed from an inorganic anion and an inorganic cation, the aromatic carboxylic acid derivative, the metal compound of the aromatic carboxylic acid derivative, and When the content of the inorganic anion is A (wt.%), B (wt.%), And C (ppm), A, B, and C satisfy the following conditions: 1/99 ≦ A / B ≦ 10/90
10 ² ≦ C
"Conductive members characterized by satisfying" are described respectively.

  In an image forming apparatus provided with a conductive roller, if the surrounding environment in which the image forming apparatus is installed changes, the internal environment also changes. Therefore, the characteristics of the conductive roller installed in the inside change and the initial state changes. May not fully function. For example, in the case where the conductive roller is a developing roller, when the humidity around the conductive roller is lowered, a predetermined amount of developer charged to a predetermined charge amount cannot be supplied to the image carrier, and a white solid is formed. A phenomenon (called fogging) in which an unnecessary developer is fixed to an image (also called a plain image) or the like may occur. This phenomenon is particularly noticeable when a color image is printed after a monochrome image is printed. As described above, when the peripheral environment of the roller mounted on the image forming apparatus changes, for example, when the peripheral humidity of the developing roller decreases, a desired image may not be obtained.

JP 2004-191655 A Japanese Patent Laid-Open No. 2005-220317 Japanese Patent No. 3804476 JP 2003-202722 A JP 2008-276022 A JP 2005-315979 A

  However, according to further studies by the present inventor, it has been found that the plain image is fogged when the peripheral humidity of the roller is changed in a decreasing direction and when the peripheral humidity is changed in the increasing direction. It was done. For example, it has been found that a conductive roller containing an ionic liquid is likely to be fogged even if the ambient humidity is changed in the increasing direction, and the fog is more prominent as the content of the ionic liquid is increased. The inventor has newly found that the occurrence of fog in a low humidity environment and the occurrence of fog in a high humidity environment are in a trade-off relationship, and it is difficult to form an image without fog in a wide range of usage environments.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a conductive roller and a developing device that contribute to forming a high-quality image without fogging even when the surrounding environment is extensive.

  An object of the present invention is to provide an image forming apparatus capable of forming a high-quality image without fogging even in a wide range of usage environments.

  In order to solve the newly found problem, the present inventor presumes that the occurrence of fogging in a low humidity environment is influenced by the overcharging of the developer supplied to the image carrier. Pay attention to the "static elimination function" that the conductive roller exhibits in a low humidity environment, and also assume that the occurrence of fogging in a high humidity environment is affected by insufficient charging of the developer. Attention was paid to the “charging function” exhibited by the conductive roller below. As a result, when the inventors have included a specific amount of ionic liquid and a specific amount of carboxylic acid metal compound in the urethane coat layer of the conductive roller, the neutralization characteristics of the ionic liquid and the charging characteristics of the carboxylic acid metal compound are increased. This synergistic action has been found to make it possible to balance “static charge function” in a low-humidity environment and “charge function” in a high-humidity environment, which had been in a trade-off relationship. Completed the invention.

  That is, the present inventor gives a developer when a relatively large amount of ionic liquid is contained in the urethane coat layer in order to further improve the image quality by keeping the charge amount given to the developer constant in a low humidity environment. Although the amount of charge is reduced and fog is likely to occur, particularly in a high humidity environment, the addition of a carboxylic acid metal compound to the urethane coat layer in addition to the ionic liquid will increase the amount of charge imparted to the developer regardless of the surrounding environment. The present invention was completed by discovering that the decrease in charge amount can be prevented while ensuring uniformity.

As means for solving the problems,
1 is a conductive roller comprising an elastic layer formed on an outer peripheral surface of a shaft body and a urethane coat layer formed on the outer peripheral surface of the elastic layer, and the urethane coat layer includes a urethane resin. And 1 to 25 parts by mass of at least one ionic liquid selected from the group consisting 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, It is a conductive roller characterized by containing 1 to 25 parts by mass of a carboxylic acid metal compound with respect to 100 parts by mass of the urethane resin.
Claim 2 is a developing device comprising the conductive roller according to claim 1,
A third aspect of the present invention is an image forming apparatus comprising the developing device according to the second aspect.

  Since the conductive roller according to the present invention contains a urethane resin, a specific amount of ionic liquid, and a specific amount of carboxylic acid metal compound, when the roller is mounted on an image forming apparatus, the normal humidity, for example, relative humidity Of course, it is formed in a low humidity environment (for example, the relative humidity is less than 50%, preferably 20% or less) or in a high humidity environment (for example, the relative humidity is more than 50%, preferably 70% or more). The occurrence of fogging in the image can be substantially suppressed. The developing device according to the present invention includes the conductive roller according to the present invention. Therefore, according to the present invention, it is possible to provide a conductive roller and a developing device that contribute to forming a high-quality image without fogging even when the surrounding environment is extensive.

  The image forming apparatus according to the present invention comprises the developing device according to the present invention. Therefore, according to the present invention, it is possible to provide an image forming apparatus capable of forming a high-quality image without fogging even in a wide range of usage environments.

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 an 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, and a urethane resin, at least one ionic liquid, and a carboxylic acid metal compound. And a urethane coat layer contained in a proportion. Thus, when the conductive roller is provided with the urethane coat layer on the outer peripheral surface of the elastic layer, the conductive roller has its conductivity, “static elimination function” in a low humidity environment, and in a high humidity environment. The “charging function” can be exerted without greatly canceling each other, that is, a uniform and desired charge amount can be imparted to the developer in a low humidity environment or a high humidity environment. As a result, the conductive roller according to the present invention can uniformly charge the developer as desired not only in a normal humidity but also in a low humidity environment and a high humidity environment. When the image forming apparatus is mounted on the developing device, it is possible to prevent fogging that may occur in the formed image even if the surrounding environment is wide. In the present invention, “no fogging” includes not only the case where there is no fogging in the image, but also the case where the image has an acceptable fogging that has no practical problem.

  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 difficult to adhere to the surface of the urethane coat layer over a long period of time, and the image forming apparatus is on standby or stopped. However, even if it continues for a long period of time, a streaky blank portion (also referred to as a white streak) in which a desired amount of developer is not fixed to an image formed thereafter, in particular, an image formed first is substantially generated. Can be suppressed.

  In the conductive roller according to the present invention, the urethane resin, the ionic liquid, and the carboxylic acid metal compound may exist independently of each other in the urethane coat layer, or exist as reactants obtained by reacting them. 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 the 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 resilience and compression of the elastic layer 3 can be increased. Excellent permanent set.

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 measured by, 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 conductivity. The shaft body 2 is made such that a gold-plated plate having a length on which the entire elastic layer 3 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 body 2 in the conductive roller 1. DC100V is applied between the electrode and the electrode, the value of the electric resistance meter after 1 second is read, and this value can be measured in accordance with a method for setting 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. This addition-curable millable conductive silicone rubber composition has (A) average composition formula: R _n SiO _{(4-n) / 2} (R may be the same or different, substituted or unsubstituted monovalent carbonization A hydrogen group, preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and n is a positive number of 1.95 to 2.05). It contains a polysiloxane, (B) a filler, and (C) a conductive material other than those belonging to the component (B). These components (A) to (C) are basically the same as the components in the “addition-curable millable conductive silicone rubber composition” described in, for example, JP-A-2008-058622. 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) a conductive material. An addition-curable liquid conductive silicone rubber composition containing a property-imparting agent and (H) an addition reaction catalyst. These components (D) to (H) are basically the same as the components in the “addition-curable liquid conductive silicone rubber composition” described in JP-A-2008-058622, for example.

  The urethane coat layer 4 is formed as an outermost layer of the conductive roller 1 with a layer thickness of preferably 0.1 to 50 μm, more preferably 10 to 25 μm. This urethane coat layer is formed by curing a urethane resin composition, which will be described later, on the outer peripheral surface of the elastic layer 3, and includes a pyridinium ionic liquid, an amine ionic liquid, and an ionic liquid having two hydroxyl groups in addition to the urethane resin. While containing at least 1 sort of ionic liquid selected in the ratio of 1-25 mass parts with respect to 100 mass parts of urethane resins, the ratio of 1-25 mass parts of carboxylic acid metal compounds with respect to 100 mass parts of urethane resins Contains.

  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 is a urethane containing a hydroxyl group-containing ionic liquid. The 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 from this urethane resin composition and a carboxylic acid metal compound, and this urethane resin is a hydroxyl group which is a urethane forming component contained in the urethane resin composition. It is formed from a containing ionic liquid, a polyol other than the hydroxyl group-containing ionic liquid, and a polyisocyanate. The content of the hydroxyl group-containing ionic liquid in this urethane resin is 1 to 25 parts by mass when the total content of polyol and polyisocyanate is 100 parts by mass. That is, the urethane coat layer 4 contains a polyol other than the hydroxyl group-containing ionic liquid, a polyisocyanate, and 1 to 25 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. It contains 1 to 25 parts by mass of a carboxylic acid metal compound when the urethane resin obtained by reaction and the total content is 100 parts by mass.

  This urethane coat layer 4 may contain, in addition to the urethane resin, the ionic liquid and the carboxylic acid metal compound, various additives usually used for 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. The urethane coat layer 4 does not substantially contain “binder resin and conductive resin particles dispersed in the binder resin” described in Patent Document 5. Here, “substantially does not contain” means not only the case where the conductive resin particles are not contained in the urethane coat layer 4 at all, but also a trace amount, for example, 100 mass of urethane resin. The case where it is contained at 5 parts by mass or less with respect to parts is also included. 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. This DBP adsorption amount can be measured according to JIS K6217-4.

  If the ionic liquid is not a hydroxyl group-containing ionic liquid, the urethane resin contained in the urethane coat layer 4, ie, the base resin that forms the urethane coat layer 4, may be a known urethane resin. , Obtained from polyol and polyisocyanate. The polyol is preferably a polyester polyol or a polyether polyol. Examples of the polyisocyanate include aliphatic polyisocyanates and aromatic polyisocyanates. Details of the polyol and polyisocyanate 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 hydroxyl group-containing ionic liquid, the polyol, and the polyisocyanate. The hydroxyl group-containing ionic liquid, specifically, the cation portion thereof is bonded to a chain or a 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 an anion, and A excludes the hydroxyl group of the hydroxyl group-containing ionic liquid. Residue. The repeating unit (II) is a polyol residue, _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 each independently _Rol . Are connected. Repeating unit (III) is a residue of a _{polyisocyanate, R IS} is a residue excluding isocyanate group of the polyisocyanate, m is an integer of 2 or more, m or more (-NHCO-) are each independently Bound to _Ris .

  The repeating units (I) to (III) are derived from the hydroxyl group-containing ionic liquid, polyol and 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 preferably 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 polyisocyanate forming the urethane resin in the ionic liquid not containing a hydroxyl group, and details thereof will be described in the urethane resin composition.

  The urethane resin is a repeating unit such that the mass of the repeating unit (I) is 1 to 25 parts by mass when the total mass of the repeating unit (II) and the repeating unit (III) is 100 parts by mass. (I) to (III). Here, the mass of the repeating unit (I) is a mass when converted to a hydroxyl group-containing ionic liquid (including an anion) before the reaction, and the mass of the repeating unit (II) is converted to a 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 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 least at a temperature near room temperature, and is also referred to as an “ionic liquid”. In the present invention, 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, it is possible to substantially suppress the occurrence of fogging in a low humidity environment and contribute to forming an image without fogging in the low humidity environment. Accordingly, the ionic liquid may be one type or a plurality as long as it is selected from the above group. This ionic liquid is an organic compound having pyridinium ions or ammonium ions as cations.

  A pyridinium-based ionic liquid is an ionic liquid having a basic skeleton of a pyridinium ion in which an alkyl group or the like is bonded to a nitrogen atom constituting a pyridine ring as a cation, 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. The alkyl group replacing the hydrogen atom and the alkyl group bonded to the nitrogen atom may be the same or different. 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, pyridine and γ-picoline are 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) and the like. 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.

  As a 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, specifically, 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.

  Further, as a pyridinium-based ionic liquid having a pyridinium ion substituted with the alkyl group as a cation and a bis (trifluoromethanesulfonyl) imide ion as 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 (trifluoro) Lomethanesulfonyl) imide, N-heptyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-octyl-2-methylpyridinium bis (trifluoromethanesulfonyl) imide 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-methyl Pyridinium 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 (trifluoro) Lomethanesulfonyl) imide, N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, N-nonyl-4-methylpyridinium bis ( Trifluoromethane sulfonyl) imide, N- decyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide, and the like. Further, as a 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 hexafluorophos Examples thereof include 1-nonyl-4-methylpyridinium hexafluorophosphate and 1-decyl-4-methylpyridinium hexafluorophosphate.

  An amine ionic liquid is an aliphatic amine 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, and has two hydroxyl groups in the molecule. Does not have. 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. One or more hydroxyl group-containing ionic liquids may be contained in the urethane resin composition. 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 fog in a low humidity environment. In addition, even if the standby or stop of the image forming apparatus is continued for a long period of time, it is preferable in that white streaks can be substantially prevented from occurring in an image formed thereafter.

  An aliphatic amine-based ionic liquid having two hydroxyl groups is an aliphatic cation having a basic skeleton of ammonium ions having two hydroxyl groups in which four substituents are bonded to nitrogen atoms of an aliphatic amine compound. It is an amine-based ionic liquid. Examples of the aliphatic amine compound include alicyclic amine compounds and aliphatic amine compounds.

Examples of the ammonium ion include (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, and have one hydroxyl group. It is a linear, branched or cyclic aliphatic organic group having 1 to 20 carbon atoms, and the remaining two of R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different. A linear, branched or cyclic alkyl group or alkenyl group of ˜20, and R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may form a ring). .

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 can substantially suppress the occurrence of fog in a low-humidity environment without greatly reducing the effects of the carboxylic acid metal compound described below. If it is particularly important to suppress the occurrence of fog in a low humidity environment, it is preferable to employ at least one ionic liquid selected from pyridinium-based ionic liquids. If it is particularly important to suppress the occurrence of the white streak after waiting or stopping, it is preferable to employ a hydroxyl group-containing ionic liquid, particularly an amine-based ionic liquid having two hydroxyl groups.

  This ionic liquid is contained in the urethane coat layer 4 at a ratio of 1 to 25 parts by mass with respect to 100 parts by mass of the urethane resin. In the present invention, since the urethane coat layer 4 contains a carboxylic acid metal compound in addition to the ionic liquid, it is possible to prevent fogging in a high humidity environment that may occur due to the presence of the ionic liquid. Therefore, the ionic liquid can be contained in a relatively large amount as compared with the conventional case, and in the present invention, the content of the ionic liquid can be 20 parts by mass or more and 25 parts by mass or less. 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 25 parts by mass, the ionic liquid bleeds out on the surface of the urethane coat layer 4 in a low humidity environment or a high humidity environment, so that a desired amount of developer is not fixed. Image quality may deteriorate due to the occurrence of white streaks that are blank portions. In addition, when the content of the ionic liquid exceeds 25 parts by mass, fogging in a high humidity environment may easily occur even if a carboxylic acid metal compound described later coexists. When the ionic liquid is a hydroxyl group-containing ionic liquid and its content exceeds 25 parts by mass, white streaks may occur in the image formed after the standby of the image forming apparatus, and the image quality may deteriorate. In the present invention, the occurrence of fogging in a low humidity environment can be substantially suppressed, and if desired, white streaks occur in an image formed thereafter even if the standby or stop of the image forming apparatus continues for a long period of time. It is preferable that content of an ionic liquid is 9-24 mass parts with respect to 100 mass parts of urethane resins at the point which can suppress doing effectively. Usually, the content of the ionic liquid in the urethane coat layer 4 is substantially the same as 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 urethane coat layer 4 contains a carboxylic acid metal compound in addition to the ionic liquid. When the metal carboxylate is contained in the urethane coat layer 4 together with the ionic liquid, the occurrence of fog in a high humidity environment can be substantially suppressed without causing fog in the low humidity environment. In particular, even when the content of the ionic liquid is increased in order to effectively suppress the occurrence of fog in a low humidity environment, the occurrence of fog in a high humidity environment can be effectively suppressed without impairing the effect. As described above, when the carboxylic acid metal compound is contained in the urethane coat layer 4, the occurrence of fogging can be prevented over a wide humidity range. One or more carboxylic acid metal compounds may be used.

  The carboxylic acid in the carboxylic acid metal compound may be a carboxylic acid that forms a metal compound such as a metal salt or a metal complex by an ionic bond, a covalent bond, or a coordinate bond with the metal, and various carboxylic acids may be mentioned. Examples of such carboxylic acids include aromatic carboxylic acids, aliphatic carboxylic acids, and alicyclic carboxylic acids. Examples of aromatic carboxylic acids include salicylic acid, benzoic acid, anthranilic acid, phenylacetic acid, naphthoic acid and their derivatives, and polyvalent carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, and trimellitic acid. And derivatives thereof. Examples of the aliphatic carboxylic acid include acetic acid, EDTA, propionic acid, butyric acid, and the like. Examples of the alicyclic carboxylic acid include naphthenic acid and cyclohexanecarboxylic acid. Among these, aromatic carboxylic acids are preferable because they can generally form stable metal compounds.

  The carboxylic acid may have various substituents, for example, preferably has a hydroxyl group or an alkoxy group that easily forms a metal salt or a metal complex, and a hydroxyl group or alkoxy at the β-position with respect to the carboxy group. Having a group is more preferable in that a stable six-membered ring metal salt or metal complex can be formed with a metal, and it is particularly preferable to have a hydroxyl group. Examples of the carboxylic acid having a hydroxyl group include aromatic hydroxycarboxylic acids such as salicylic acid, hydroxynaphthoic acid and derivatives thereof, aliphatic hydroxycarboxylic acids such as 2-hydroxyethanoic acid and 2-hydroxypropanoic acid, and hydroxymethylcyclohexanecarboxylic acid. And alicyclic hydroxycarboxylic acids such as hydroxymethylnorbornenecarboxylic acid and hydroxymethyltricyclodecanecarboxylic acid.

  This carboxylic acid may have another substituent, for example, an aliphatic substituent or an aromatic group, instead of or in addition to the hydroxyl group or the alkoxy group. Examples of the aliphatic substituent include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, n- Examples include pentyl group, i-pentyl group, s-pentyl group, n-hexyl group, i-hexyl group, s-hexyl group and the like. Examples of the aromatic group include a phenyl group, a methylphenyl group, and an ethylphenyl group. The carboxylic acid may have one or more kinds of such other substituents, and preferably has an aliphatic substituent, particularly preferably a plurality of the same aliphatic substituent. Examples of such carboxylic acids having other substituents include alkyl salicylic acid and dialkyl salicylic acid. Examples of the alkyl salicylic acid include 3-methyl salicylic acid, 3-ethyl salicylic acid, 3-t-butyl salicylic acid, 5-methyl salicylic acid, 5-ethyl salicylic acid, 5-t-butyl salicylic acid and the like. Examples of the dialkyl salicylic acid include 3,5-dimethylsalicylic acid, 3,5-diethylsalicylic acid, 3,5-di (t-butyl) salicylic acid, and the like.

  The metal in a carboxylic acid metal compound should just be a metal which forms metal compounds, such as a metal salt and a metal complex, by ionic bond, a covalent bond, or a coordinate bond with carboxylic acid, and various metals are mentioned. Examples of such a metal include zinc, iron, aluminum, chromium, gallium, magnesium, titanium, zirconium, hafnium, copper, nickel, and cobalt. Among these, metals such as zinc and chromium are preferable, and zinc is particularly preferable in that the effect of imparting charge to the developer is high.

  A carboxylic acid metal compound composed of a carboxylic acid and a metal is represented by the following chemical formula (wherein R is the aliphatic substituent or the aromatic group) in that the object of the present invention can be satisfactorily achieved. A zinc compound composed of dialkyl salicylic acid and zinc, or a chromium compound composed of dialkyl salicylic acid and chromium in which Zn of the following chemical formula is replaced with Cr is preferred, and a zinc compound composed of dialkyl salicylic acid and zinc is particularly preferred. preferable. Examples of such a zinc compound include zinc 3,5-dimethylsalicylate, zinc 3,5-diethylsalicylate, zinc 3,5-di (t-butyl) salicylate, and the like, and 3,5-di (t -Butyl) zinc salicylate is preferred. Examples of such a chromium compound include chromium 3,5-dimethylsalicylate, chromium 3,5-diethylsalicylate, chromium 3,5-di (t-butyl) salicylate, and the like, and 3,5-di (t -Butyl) chromic salicylate is preferred.

  The carboxylic acid metal compound is contained in the urethane coat layer 4 at a ratio of 1 to 25 parts by mass with respect to 100 parts by mass of the urethane resin. When the content of the carboxylic acid metal compound is less than 1 part by mass, the effect of the carboxylic acid metal compound may not be sufficiently obtained, and the occurrence of fogging in a high humidity environment may not be suppressed. On the other hand, when the content of the carboxylic acid metal compound exceeds 25 parts by mass, the carboxylic acid metal compound may bleed out on the surface of the urethane coat layer 4 to generate white streaks, which may reduce the image quality. In this invention, the content of the carboxylic acid metal compound is 2 with respect to 100 parts by mass of the urethane resin in that the generation of the fog in the high humidity environment can be suppressed while effectively suppressing the generation of the fog in the low humidity environment. It is preferably ˜15 parts by mass, particularly preferably 6 to 14 parts by mass. Usually, the content of the carboxylic acid metal compound in the urethane coat layer 4 substantially matches the content of the carboxylic acid metal compound 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 urethane resin composition for forming the urethane coat layer 4 includes a urethane adjusting component that is a precursor for forming a urethane resin, 1 to 25 parts by mass of an ionic liquid with respect to a predetermined amount, that is, 100 parts by mass of the urethane adjusting component, It contains 1 to 25 parts by mass of a carboxylic acid metal compound and optionally various additives with respect to 100 parts by mass of the urethane adjustment component. Therefore, the urethane coat layer 4 has a urethane resin composition containing a urethane adjusting component, a predetermined amount of ionic liquid, a predetermined amount of carboxylic acid metal compound, and various additives as required on the outer peripheral surface of the elastic layer 3. It is formed by coating and curing. The ionic liquid, the carboxylic acid metal compound, 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. And the like. Examples of the polyester polyol include condensation-type polyester polyols, lactone-type polyester polyols, polycarbonate polyols, and mixtures thereof obtained by condensation of dicarboxylic acids such as adipic acid and polyols such as ethylene glycol and hexanediol. It is done. The polyether polyol and the polyester polyol may be used alone 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. When the ionic liquid is a hydroxyl group-containing ionic liquid, the polyisocyanate is preferably a diisocyanate, and a high-quality image can be obtained even after the image forming apparatus has been on standby or stopped for a long period of time or in a low humidity environment. Aliphatic polyisocyanates are preferred in that they can be formed, and therefore aliphatic diisocyanates are particularly preferred.

  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. Polyisocyanate can be used alone or in combination of two or more. The polyisocyanate preferably has a molecular weight of 500 to 2000, more preferably 700 to 1500.

  Although the mixing ratio of the hydroxyl group-containing ionic liquid and the polyisocyanate is not particularly limited when the polyol is contained, 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. The ratio [NCO / OH] between the total number of moles and the number of moles of isocyanate groups (NCO) contained in the polyisocyanate is preferably 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 25 parts by mass when the total content of polyol and 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 25 parts by mass, the ionic liquid is formed as described above. Image quality may be degraded. The occurrence of fogging in a low humidity environment can be substantially suppressed, and if desired, even if the standby or stop of the image forming apparatus continues for a long period of time, white streaks occur in the image formed thereafter. In terms of effective suppression, the content of the ionic liquid is preferably 9 to 24 parts by mass when the total content of polyol and polyisocyanate is 100 parts by mass.

  The carboxylic acid metal compound in the urethane resin composition is 1 to 25 parts by mass when the total content of polyol and polyisocyanate is 100 parts by mass. When the content of the carboxylic acid metal compound is less than 1 part by mass, as described above, the effect of the carboxylic acid metal compound may not be sufficiently obtained. On the other hand, when the content exceeds 25 parts by mass, as described above. In some cases, the quality of the image formed on the screen may deteriorate. The content of the carboxylic acid metal compound is 2 to 15 parts by mass when the total content of the polyol and the polyisocyanate is 100 parts by mass in that the fog in the low humidity environment and the fog in the high humidity environment can be suppressed. It is preferable that it is 6-14 mass parts.

  In the urethane resin composition, in addition to the urethane adjusting component, the ionic liquid and the carboxylic acid metal compound, an auxiliary agent usually used for the reaction between the polyol and the polyisocyanate, for example, a chain extender, a crosslinking agent and the like are used in combination. Also good. Examples of chain extenders and crosslinking agents include glycols, hexanetriol, trimethylolpropane, and amines.

  The urethane resin composition is obtained by mixing a urethane adjusting component, an ionic liquid, a carboxylic acid metal compound, and, if desired, a solvent, an auxiliary agent and the like by an appropriate method.

  A method for manufacturing a conductive roller according to the present invention will be described below by taking the conductive roller 1 as an example.

  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, The resin similar to the material which forms the primer layer which adhere | attaches or closely_contact | adheres the elastic layer 3 and the urethane coat layer 4, and a crosslinking agent 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, 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, 120 Secondary vulcanization may be carried out at about 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 is, for example, a coating method of coating a urethane resin composition coating solution, a dipping method of immersing the elastic layer 3 or the like in the coating solution, or spraying the coating solution onto the elastic layer 3 or the like. It is performed by a known coating method such as a spray coating method. 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. Instead of the coating, the urethane resin composition is 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, or after the lamination. A method of curing the laminated urethane resin composition or the like can be employed.

  The conductive roller 1 is at least selected from the group consisting of urethane resin and 1 to 25 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 urethane resin. Since the urethane coating layer 4 containing 1 type of ionic liquid and 1 to 25 parts by mass of a carboxylic acid metal compound with respect to 100 parts by mass of the urethane resin is provided, as described above, in the image forming apparatus. When mounted, the developer can be given a uniform and desired charge amount in both low and high humidity environments, and high-quality images without fogging can be obtained even if the surrounding environment is extensive. Can contribute to the formation. That is, the conductive roller 1 can contribute to forming a high-quality image without fogging even when the surrounding humidity changes to low humidity or to high humidity.

  In the case where the conductive roller 1 includes the urethane coat layer 4 containing the hydroxyl group-containing ionic liquid, in addition to preventing the occurrence of the fog, the conductive roller 1 mounted on the image forming apparatus includes the image carrier. Even if the image forming apparatus is in contact with or pressed against a contacted body such as the image forming apparatus for a long period of time, for example, for 5 days or more, the image forming apparatus is subsequently operated to form an image. The occurrence of white stripes can be substantially suppressed. 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 abutted body with which the conductive roller 1 abuts, so that the uniformity of the urethane coat layer 4 is not impaired or the abutted 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, the low humidity can be maintained even after the image forming apparatus is on standby or stopped for a long period of time or in a low humidity environment. Even under the environment, the image forming apparatus can contribute to forming a high-quality image. Moreover, even if the conductive roller 1 contains 1 to 25 parts by mass of the ionic liquid in the urethane coat layer 4, and particularly 20 parts by mass or more, the ionic liquid is difficult to bleed out from the urethane coat layer 4. . 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 contacts.

  As described above, the conductive roller 1 can substantially suppress the occurrence of fogging even when the surroundings are at low humidity or high humidity, and if desired, the image forming apparatus can be on standby or stopped for a long period of time. Since the generation of white streaks can be substantially suppressed later, for example, the developer charged to a desired charge amount on the surface of the developer is uniformly supported and supplied to the image carrier. -It is suitably used as a developing roller and a developer supply roller that need to perform its function, and particularly as a developing roller and a developer supply roller that are mounted in contact with or pressed against a contacted body such as an image carrier. Preferably used.

  In addition, even when the conductive roller 1 is attached to a monochrome image forming apparatus that easily generates fog in a high humidity environment, the occurrence of fog in the high humidity environment can be effectively prevented. Therefore, the conductive roller 1 is suitably mounted not only on a color image forming apparatus but also on a monochrome image forming apparatus.

  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 provided in the developing units B, C, M, and Y of the respective colors in series on the 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 the casing 21B that accommodates the one-component non-magnetic developer 22B, the developer carrier 23B that supplies the developer 22B to the image carrier 11B, for example, the developing roller, and the thickness of the developer 22B. Developer amount adjusting means 24B, for example, a blade is provided. 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 may be, for example, a dry developer or a wet developer, and nonmagnetic development. An agent or a magnetic developer may be used. One component non-magnetic black developer 22B, cyan developer 22C, magenta developer 22M and yellow developer 22Y are accommodated in the housings 21B, 21C, 21M and 21Y of the developing units.

  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 medium 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 each of the developing devices 20B, 20C, 20M, and 20Y includes the conductive roller 1 as the developer carrier 23B, 23C, 23M, and 23Y, the humidity inside the developing device, for example, the humidity around the developer carrier 23 The image forming apparatus 10 can contribute to forming a high-quality image without fogging even if the humidity changes to low humidity or high humidity.

  In the tandem type image forming apparatus 10, the conductive roller 1 is mounted as the developer carrying member 23, so that the fog is substantially not only in a normal humidity but also in a low humidity environment and in a high humidity environment. High quality images can be formed. Further, when the conductive roller 1 is mounted as the developer carrier 23, the tandem type image forming apparatus 10 does not contaminate the image carrier 11 due to bleeding out of the ionic liquid or the metal carboxylate. High quality images can be formed. Further, even if the tandem type image forming apparatus 10 is on standby or stopped for a long period of time, the uniformity of the urethane coat layer 4 of the conductive roller 1 is not impaired. Even if it continues for a long time, a high quality image substantially free of white streaks can be formed.

  The image forming apparatus 10 is an image forming apparatus such as a copying machine, a facsimile machine, or a printer. The image forming apparatus 10 has been described with reference to an example in which the conductive roller according to the present invention is used as a developing roller as an example of the developer carrier 23. However, the conductive roller according to the present invention is used as a developer supply roller. Even if a roller 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 examples, and various modifications can be made within a range in which 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 the electrophotographic system, and may be, for example, an electrostatic image forming apparatus. . 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, the content (parts by mass) of the ionic liquid and the carboxylic acid metal compound when the total content of the following polyols and polyisocyanates is 100 parts by mass is expressed as “converted content (parts by mass)”. And shown in Table 1.

-14 parts by mass of polyisocyanate (hexamethylene diisocyanate)-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.)" 4 parts by mass- "Zinc 3,5-di (t-butyl) salicylate (trade name" BONTRON E-84 ", manufactured by Orient Chemical Co., Ltd.)" 4 parts 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 ", manufactured by 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 to 5)
The conductive rollers were each basically the same as Example 1 except that the content of the carboxylic acid metal compound in the urethane composition was changed to 1 part by weight, 2 parts by weight, 8 parts by weight and 10 parts by weight. Manufactured.

(Examples 6 to 9)
A conductive roller was produced in the same manner as in Example 1 except that the content of the ionic liquid in the urethane composition was changed to 2 parts by mass, 6 parts by mass, 8 parts by mass, and 10 parts by mass. .

(Examples 11 to 19)
Instead of the above-mentioned “C ₅ H ₅ N ⁺ —C ₆ H ₁₃ [(CF ₃ SO ₂ ) ₂ N] ⁻ ” as the ionic liquid, “(CH ₃ ) ₃ N ⁺ C ₃ H ₆ [ ^{_{(CF 3 SO 2) 2 N}} ] - (N, N, N- trimethyl -N- propyl ammonium bis (trifluoromethanesulfonyl) imide), except for using Kanto Chemical Co., Ltd. "" examples 1-9 In the same manner, conductive rollers were respectively manufactured.

(Example 21)
Instead of “zinc 3,5-di (t-butyl) salicylate” as a metal carboxylate compound, “3,5-di-t-butylsalicylate chromium” (trade name “BONTRON S-34”, Orient Chemical Industries, Ltd. A conductive roller was produced basically in the same manner as in Example 1 except that the above-mentioned product was used.

(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 in the urethane composition was changed to 6 parts by mass. did.
(Comparative Examples 3 and 4)
Conductive rollers were produced in substantially the same manner as in Example 1 except that the content of the pyridinium-based ionic liquid in the urethane composition was changed to 0.2 parts by mass and 12 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 carboxylic acid metal compound was not contained.
(Reference Examples 2 and 3)
A conductive roller was produced in substantially the same manner as in Example 1 except that the content of the carboxylic acid metal compound in the urethane composition was changed to 0.2 parts by mass and 12 parts by mass.

(Evaluation of fogging in a low humidity environment)
Each manufactured conductive roller is mounted on a non-magnetic one-component electrophotographic printer (trade name “HL-4040CN”, manufactured by Brother Industries, Ltd.) as a developing roller, and in a low humidity environment of 23 ° C. (relative humidity 10%). ) For 24 hours. This printer is one of “contact type image forming apparatuses”, and the developing device mounted is a so-called “contact type developing device”, which contains a positively charged developer. Thereafter, the printer was set to “plain paper thick”, the print quality was set to “standard”, and the color setting was set to “standard”, and 100 white images were continuously printed in the monochrome mode. Immediately thereafter, the setting was changed to the color mode, and a single solid image was printed. The degree of contamination of the white solid image printed in this color mode was visually evaluated as a fog. The evaluation is “◎” when there is no dirt on the entire white solid image, “○” when the white solid image is slightly dirty to the extent that there is no practical problem, and practical for white solid images. The case where some stains were recognized to the extent that there was no problem was indicated as “Δ”, and the case where stains were found to be unacceptably practical for white solid images was indicated as “x”. These evaluation results are shown in Table 1 as “low moisture fog”.

(Evaluation of fogging in high humidity environment)
Except for the evaluation under a high humidity environment of 32.5 ° C. (80% relative humidity), the evaluation of the fog under a high humidity environment was performed basically in the same manner as the “fogging evaluation under a low humidity environment”. These evaluation results are shown in Table 1 as “high humidity fog”.

(Image quality evaluation 1)
As image quality evaluation 1, the presence or absence of white streak by preventing bleed-out in a high humidity environment was evaluated. Specifically, each manufactured conductive roller is mounted as a developing roller on a non-magnetic one-component electrophotographic printer (trade name “HL-4040CN”, manufactured by Brother Industries, Ltd.), and the surrounding environment is 32.5. It was set in a high-humidity environment at 80 ° C. (relative humidity 80%) and allowed to stand without operating for 5 days. Thereafter, the image bearing member was taken out from the printer and visually confirmed. As a result, contamination of the image bearing member could not be confirmed. This image carrier was re-installed in the printer, and a single color image was printed with the paper setting of the printer set to “plain paper thick”, the print quality set to “standard”, and the color setting set to “color mode”. . The presence or absence of white streaks in this color image was visually evaluated. The evaluation is “◎” when there is no white streak in the color image, “○” when there is a slight white streak to the extent that there is no practical problem in the color image, and there is a practical problem in the color image. The case where some white streaks were recognized to the extent that they were not “Δ”, and the case where white streaks were found to be unacceptable for practical use in color images was marked “x”.

(Image quality evaluation 2)
As image quality evaluation 2, the presence or absence of white streak by preventing bleed out in a low humidity environment was evaluated. Specifically, white streaks were evaluated in a low-humidity environment in the same manner as “Image Quality Evaluation 1” except that the evaluation was performed in a low-humidity environment of 23.0 ° C. (relative humidity 10%). .

(Comprehensive evaluation)
Comprehensive evaluation of the presence or absence of white streak by preventing bleed-out in high-humidity environment or low-humidity environment (indicated as “image quality evaluation” in Table 1), the evaluation results of image quality evaluation 1 and image quality evaluation 2 are “◎ and ◎ ”Or“ ◎ and ○ ”is“ ◎ ”, and when the evaluation results of the image quality evaluation 1 and the image quality evaluation 2 are“ ○ and ○ ”or“ ○ and △ ”, the image quality evaluation 1 And the evaluation result of the image quality evaluation 2 is “Δ” and “Δ”, and the evaluation result of the image quality evaluation 1 and the image quality evaluation 2 is “× and ×” or “Δ and X”. × ”. The results are shown in Table 1.

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 Recording body 20 Developing devices 21B, 21C, 21M, 21Y, 34 Housings 22B, 22C, 22M, 22Y Developers 23B, 23C, 23M, 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 (3)

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 25 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 1 to 25 parts by mass of a carboxylic acid metal compound with respect to 100 parts by mass of the urethane resin.   A developing device comprising the conductive roller according to claim 1.   An image forming apparatus comprising the developing device according to claim 2.

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