JP2009223134A - Endless belt and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt that is small in resistance even if the environment changes and that can prevent contamination of abutting members, and to provide an image forming apparatus that can form a high quality image. <P>SOLUTION: The endless belt 1 includes an endless belt substrate 2, and an elastic layer 3 formed on the endless belt substrate 2. The elastic layer 3 contains at least one kind of an ion conductive agent selected from a group consisting of an organic boron complex salt, ionic liquid, and perchlorate of alkali metal. The image forming apparatus has this endless belt. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an endless belt and an image forming apparatus. More specifically, even if the environment changes, an endless belt capable of preventing the contamination of a contacting member with a small variation in resistivity, and a high-quality image. It is related with the image forming apparatus which can form.

  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 is, for example, a direct transfer system that directly transfers a developer image developed on an image carrier to a recording body according to the function of an endless belt, and a developer image that is once endless. There is an intermediate transfer method in which the image is transferred to a belt and transferred from an endless belt to a recording medium.

  In the direct transfer method, an electrostatic latent image formed on an image carrier such as a photosensitive drum is developed with a developer supplied from a developer carrier provided in the developing unit, and a voltage is applied to the transfer unit. The developer image electrostatically attracted to the endless belt (also referred to as a transfer conveyance belt) and transferred to the recording medium conveyed between the image carrier and the transfer unit is transferred, and the developer image is transferred. In this system, the recorded body is pressed or heat-pressed by a pressure roller and a fixing roller, and the transferred developer image is fixed on the recording body as an image or a character.

  In the intermediate transfer system, for example, an electrostatic latent image formed on an image carrier is developed with a developer, and the developed developer image is contacted or pressed against the image carrier (also referred to as an intermediate transfer belt). ) (Primary transfer), the developer image transferred to the endless belt is transferred to the recording body (secondary transfer), and the recording body onto which the developer image has been transferred is pressure-bonded or pressed by a pressure roller and a fixing roller. This is a system in which the developer image transferred by thermocompression bonding is fixed as an image or text on the recording medium. Such an intermediate transfer type image forming apparatus is widely used because it has a good developer transfer property, and it is relatively easy to realize colorization and high definition of an image and high image forming speed. ing.

  As described above, the endless belt attached to the intermediate transfer type image forming apparatus receives the developer as a developer image from the image carrier, and then supplies the developer as a developer image to the recording body. Therefore, in order to receive the developer as desired and supply it as desired, the endless belt has an electrical characteristic such as a common logarithm value of conductivity (volume resistivity (unit: Ω · cm)) of 6 to 13) is required. Examples of the endless belt having such electrical characteristics include an endless belt containing an ionic conductive agent. Specifically, Patent Document 1 (Claim 1) describes “intermediate transfer member characterized by using a conductive material containing a specific quaternary ammonium salt as an ionic conductive agent”.

  Further, the endless belt may have a multilayer structure for the purpose of improving the transferability and releasability of the developer and improving the durability. As an endless belt having such a multilayer structure, for example, “an electronic conductive semiconductive layer formed using an electronic conductive semiconductive synthetic resin material whose volume resistivity is adjusted by blending an electronic conductive filler; A conductive plastic belt characterized in that it is formed by laminating an ion conductive semiconductive layer formed using an ion conductive semiconductive material whose volume resistivity is adjusted by blending an ion conductive agent. It is described in Patent Document 2 (Claim 1). As an ionic conductive agent used for this conductive plastic belt, “quaternary ammonium salt, phosphate ester, aliphatic alcohol sulfate salt, amine perchlorate” and specific compounds thereof are described in Patent Document 2. It is described in the column.

  By the way, since the internal environment of any image forming apparatus changes when it is operated, the endless belt is electrically connected to the above-mentioned electrical characteristics even if the surrounding environment where the endless belt is attached changes. It is required that the characteristics do not vary greatly. However, in the conventional endless belt, the electrical characteristics, particularly the resistivity, may fluctuate when the surrounding environment in which the endless belt is mounted changes. If the electrical characteristics of the endless belt fluctuate due to changes in the surrounding environment, for example, if the resistivity decreases, the developer cannot be received and supplied as desired, i.e., the transferability of the developer is reduced. As a result, the quality of the formed image is greatly reduced. As described above, when the electric characteristics of the endless belt fluctuate, the performance of “higher image definition” and / or “higher image formation speed” in the intermediate transfer type image forming apparatus cannot be sufficiently exhibited. .

  On the other hand, the ionic conductive agent contained in the endless belt may move to the surface of the endless belt, for example, when the surrounding environment changes, particularly in a high temperature and high humidity environment. When the ionic conductive agent moves to the surface of the endless belt, the member, for example, the image carrier, in contact with the endless belt mounted on the image forming apparatus is contaminated. As a result, the contaminated member, for example, the image carrier cannot carry the developer as desired, and the quality of the formed image is deteriorated. Therefore, even if the surrounding environment to which the endless belt is attached changes, particularly when the surrounding environment changes to a high-temperature and high-humidity environment due to the operation of the image forming apparatus, contamination of the member with which the endless belt is in contact is prevented. It is desired to prevent it.

Japanese Patent No. 3750568 JP-A-8-110711

  The present invention provides an endless belt capable of preventing the contamination of a contact member with a small variation in resistivity even when the environment changes, and can form a high-quality image. An object of the present invention is to provide an image forming apparatus.

As means for solving the problems,
Claim 1 comprises an endless belt base and an elastic layer formed on the endless belt base, wherein the elastic layer is composed of an organic boron complex salt, an ionic liquid, and an alkali metal perchlorate. It is an endless belt characterized by containing at least one ionic conductive agent selected from
A second aspect of the present invention is an image forming apparatus including the endless belt according to the first aspect.

  Since the endless belt according to the present invention includes an elastic layer containing at least one ionic conductive agent selected from the group consisting of an organic boron complex salt, an ionic liquid, and an alkali metal perchlorate, the endless belt Even if the surrounding environment where the is attached is changed to a high-temperature and high-humidity environment, it has substantially constant electrical characteristics, particularly resistivity, and can prevent the ion conductive agent from transferring to the elastic layer surface. Therefore, according to the present invention, it is possible to provide an endless belt in which the variation in resistivity is small and the contamination of the contacting member can be prevented even when the environment changes, and the endless belt according to the present invention And an image forming apparatus capable of forming a high-quality image.

  An endless belt which is an embodiment of an endless belt according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the endless belt 1 includes an endless belt base 2 and an elastic layer 3 formed on the outer peripheral surface of the endless belt base 2.

  As shown in FIG. 1, the endless belt base 2 is formed by curing a resin composition described later, and has a single layer structure. The endless belt base 2 has a desired width and inner peripheral diameter depending on the use of the endless belt 1, that is, the position (component) disposed in the image forming apparatus, the interval between a plurality of stretched rollers, and the like. Is set. Although the thickness of the endless belt base | substrate 2 is not specifically limited, Usually, it is preferable that it is 50-200 micrometers, for example, it is more preferable that it is 60-170 micrometers, and it is especially preferable that it is 70-160 micrometers. When the thickness of the endless belt substrate 2 is within the above range, the mechanical strength and flexibility when the endless belt 1 is obtained can be secured, and the durability of the endless belt 1 is excellent. The thickness of the endless belt base 2 can be measured by a contact-type film thickness meter or a non-contact-type film thickness meter, for example, an overcurrent film thickness meter (trade name “CTR-1500E”, Sanko Electronics Co., Ltd.). Can be used.

  The endless belt base 2 preferably has a common logarithmic value of volume resistivity (unit: Ω · cm) within a range of 6 to 13 under conditions of a temperature of 23 ° C. and a relative humidity of 50%. It is particularly preferable to be within the range. When the endless belt base 2 has a common logarithmic value of the volume resistivity in the above range, the volume resistivity when the endless belt 1 is used can be adjusted to a desired range, and as a result, the electrostatic adsorption force Since the developer is received and carried as desired and can be supplied as desired, a high-quality image can be formed. The common logarithm of the volume resistivity of the endless belt base 2 is the volume resistivity measured by a volume resistance measuring device (Mitsubishi Chemical Corporation, trade name: Hiresta-UP, probe used: URS). It can be obtained by converting to a numerical value.

  The endless belt base 2 preferably has a common logarithmic value of the surface resistivity (unit: Ω / □) in the range of 7 to 14 under the conditions of a temperature of 23 ° C. and a relative humidity of 50%. It is particularly preferable to be within the range. When the endless belt substrate 2 has a common logarithmic value of the surface resistivity in the above range, the surface resistivity when the endless belt 1 is used can be adjusted to a desired range, and as a result, the electrostatic attraction force Since the developer is received and carried as desired and can be supplied as desired, a high-quality image can be formed. The common logarithmic value of the surface resistivity of the endless belt substrate 2 is a circular electrode (for example, trade name: Hirosta-UP, used probe: URS probe) manufactured by Mitsubishi Chemical Corporation, and the surface resistivity is measured according to JIS K6911. And it can obtain | require by converting a measured value into a common logarithm value.

  The common logarithmic value of the volume resistivity and the common logarithm of the surface resistivity of the endless belt substrate 2 are, for example, the type, content, and / or the conductivity imparting agent contained in the resin composition described later that forms the endless belt substrate 2. Or it can adjust with molding conditions etc.

  The endless belt base 2 is formed by curing a composition containing a resin. The resin composition is preferably a resin composition having a certain level of strength and containing a single resin or a plurality of types of resins that are resistant to repeated deformation and is highly flexible, and is contained in such a resin composition. Examples of the resin include a thermoplastic resin and a thermosetting resin. Examples of the thermoplastic resin and thermosetting resin include acrylic resin, acrylic / styrene copolymer, polystyrene, acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer (ABS resin), acetyl cellulose, and polyamideimide. Resin (PAI), polyimide resin (PI), polyamide resin (PA), aramid resin, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyester resins such as cross-linked polyester resin, Fluorine resin, polysulfone resin, polyethersulfone resin (PESF), polycarbonate (PC), polyphenylene oxide (PPO), polyphenylene oxide / polystyrene copolymer, polyphenylene resin Fido (PPS), tetrafluoride resin (PTFE), polymethyl pentene (TPX), polyarylate (PAR), polyacetal (POM), polyetheretherketone (PEEK), epoxy resins, melamine resins, and the like. Among these, thermosetting resins such as polyamideimide resin, polyimide resin, and polyamide resin are preferable, and polyamideimide resin is more preferable. In particular, aromatic polyamideimide resin has strength, flexibility, dimensional stability, and heat resistance. It is preferable in terms of excellent mechanical properties such as a good balance.

  The aromatic polyamideimide resin can be produced by a diisocyanate method in which a tricarboxylic acid anhydride and a diisocyanate compound are reacted, and the diisocyanate method is excellent in terms of availability of raw materials, reactivity and less by-products. . In addition to the aromatic polyamideimide resin produced by the diisocyanate method, an aromatic polyamideimide resin produced using a diamine compound instead of the diisocyanate compound can be used as long as the polycondensation reaction can be suitably advanced. preferable. An aromatic polyamideimide resin obtained using a diamine compound has a high Young's modulus and is suitable as a resin contained in a resin composition forming an endless belt. Moreover, the aromatic polyamide-imide resin in which part of the tricarboxylic acid anhydride is replaced with tetracarboxylic dianhydride to increase the imide bond is excellent in moisture resistance. The aromatic polyamideimide resin can be easily synthesized by reacting in an appropriate solvent under normal pressure and at normal temperature or under heating.

  The tricarboxylic acid anhydride is preferably an aromatic tricarboxylic acid anhydride, such as trimellitic acid anhydride, 3,4,4′-diphenyl ether tricarboxylic acid anhydride, 3,4,4′-benzophenone tricarboxylic acid anhydride. 2,3,5-pyridinetricarboxylic acid anhydride, naphthalenetricarboxylic acid anhydride, and derivatives thereof. These acid anhydrides can be used alone or in combination of two or more.

  Examples of the tetracarboxylic dianhydride used in place of a part of the tricarboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3, 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2, 2'-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride Bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, and derivatives thereof. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

  Preferred examples of the diisocyanate compound include aromatic diisocyanate compounds. In addition, as the diisocyanate compound, an aliphatic diisocyanate compound and / or an alicyclic diisocyanate compound, or amines that are derivatives thereof can be used together with or in place of the aromatic diisocyanate compound.

  Examples of the aromatic diisocyanate compound include m-phenylene diisocyanate, p-phenylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 4,4′-diisocyanate diphenyl ether, 4,4′-diisocyanate diphenyl sulfone, and 4,4′-diisocyanate. Biphenyl, 3,3′-dimethyl-4,4′-diisocyanate biphenyl, 2,4-toluene diisocyanate, xylylene diisocyanate and the like can be mentioned. Diamines that are derivatives of these aromatic diisocyanate compounds can also be used as raw materials. Examples of the aliphatic diisocyanate compound include ethylene diisocyanate, propylene diisocyanate, and hexamethylene diisocyanate. Examples of the alicyclic diisocyanate compound include 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like. Among these diisocyanate compounds, considering the heat resistance, mechanical properties and solubility of the endless belt, 60% by mass or more, preferably 70% by mass or more of all diisocyanate compounds used is diphenylmethane-4,4 ′. -Diisocyanate, 2,4-toluene diisocyanate, 3,3'-dimethyl-4,4'-diisocyanate biphenyl, isophorone diisocyanate or a diamine which is a derivative thereof is preferable. Furthermore, considering the dimensional stability of the endless belt 1, 70% by mass or more of all diisocyanate compounds used may be diphenylmethane-4,4′-diisocyanate or its derivative 4,4′-diaminodiphenylmethane. preferable.

  As the solvent used in the polycondensation reaction for synthesizing the aromatic polyamideimide resin, a polar solvent is preferable in terms of solubility, and an aprotic polar solvent is particularly preferable in consideration of reactivity. Examples of aprotic polar solvents include N, N-dialkylamides, and examples of N, N-dialkylamides include N, N-dimethylformamide, N, N-dimethylacetamide, N, N- Examples include diethylformamide, N, N-diethylacetamide, and N, N-dimethylmethoxyacetamide. Further, as a polar solvent, N-methyl-2-pyrrolidone, pyridine, dimethyl sulfoxide, tetramethylene sulfone, dimethyltetramethylene sulfone, and the like are also preferable. These solvents can be used alone or in combination of two or more.

The resin composition may contain a conductivity imparting agent. Examples of the conductivity-imparting agent include conductive powder. As the conductive powder, for example, in addition to conductive carbon such as ketjen black and acetylene black, rubber carbons such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, titanium oxide, and oxidation Examples thereof include metals such as zinc, nickel, copper, silver, germanium, metal oxides, conductive polymers such as polyaniline, polypyrrole, and polyacetylene, and nanoparticles. Moreover, the said ion conductive agent can also be used as an electroconductivity imparting agent. Among these, conductive carbon and carbon for rubber are preferable, and carbon black is particularly preferable. As the conductivity-imparting agent, one of these various substances can be used alone, or two or more of them can be used in combination. A preferable shape of the conductivity-imparting agent is spherical or irregular. The size of the particles of the conductivity-imparting agent having a spherical or irregular shape is preferably about 0.01 to 10 μm as the primary particle diameter. If conductive agent is carbon black, the BET specific surface area, strong correlation between the primary particle diameter is preferably ^{50~300m 2 / g, 100~200m 2 /} g is more preferable.

  The content of the conductivity-imparting agent in the resin composition may be appropriately adjusted depending on the conductivity and particle size of the conductivity-imparting agent and the conductive properties required for the endless belt. It is preferably 1 to 25% by mass, more preferably 5 to 20% by mass, and particularly preferably 10 to 20% by mass with respect to 100% of the total mass with the conductivity-imparting agent. If the addition amount of the conductivity-imparting agent is less than 1% by mass, the distance between the conductive materials may be too far apart, and the expression of conductivity in the endless belt may deteriorate, while the addition amount of the conductivity-imparting agent is 25. When it exceeds mass%, the mechanical strength of the endless belt substrate may be lowered. In order to disperse the conductivity-imparting agent in the resin, a known method can be appropriately selected. Examples of known methods include mixing rolls, pressure kneaders, extruders, three rolls, homogenizers, ball mills, pot mills, and the like. The mixing method using bead mill etc. is mentioned.

  Unless the objective of this invention is inhibited, the resin composition may contain other components in addition to the resin and the conductivity imparting agent. Examples of other components include silicone compounds, fluorine organic compounds, coupling agents, lubricants, antioxidants, plasticizers, colorants, antistatic agents, anti-aging agents, reinforcing fillers, reaction aids, Examples include various additives such as reaction inhibitors. The resin composition may contain other resins as long as the object of the present invention is not impaired. The content of these other components in the resin composition can be appropriately determined according to the characteristics developed in the resin composition by the addition of these other components.

  As shown in FIG. 1, the elastic layer 3 is formed by curing a rubber composition, which will be described later, on the outer peripheral surface of the endless belt base 2 and has a single layer structure. Therefore, the elastic layer 3 has the same inner peripheral diameter as the outer peripheral diameter of the endless belt base 2 and has the same width as the width of the endless belt base 2. The thickness of the elastic layer 3 should just be adjusted to the thickness which has elasticity with the rubber composition mentioned later, Usually, it is preferable that it is 50-400 micrometers, it is more preferable that it is 70-300 micrometers, and 100-250 micrometers. Is particularly preferred. When the thickness of the elastic layer 2 is within the above range, when the endless belt 1 is mounted on the image forming apparatus, a contact width between the endless belt 1 and a member with which the endless belt 1 contacts is secured, and development is performed. Good transferability of the agent can be realized. The thickness of the elastic layer 3 can be measured in the same manner as the thickness of the endless belt base 2.

  The elastic layer 3 preferably has a common logarithmic value of volume resistivity (unit: Ω · cm) within a range of 7 to 13 under conditions of a temperature of 23 ° C. and a relative humidity of 50%. It is particularly preferred that it is within the range. When the elastic layer 3 has a common logarithmic value of the volume resistivity in the above range, the volume resistivity when the endless belt 1 is used can be adjusted to a desired range, and as a result, the electrostatic attraction force is Strongly, the developer can be received and carried as desired and fed as desired, so that a high quality image can be formed.

  The elastic layer 3 preferably has a common logarithmic value of the surface resistivity (unit: Ω / □) within a range of 7 to 13 under conditions of a temperature of 23 ° C. and a relative humidity of 50%. It is particularly preferred that it is within the range. When the elastic layer 3 has a common logarithm value of the surface resistivity in the above range, the surface resistivity when the endless belt 1 is used can be adjusted to a desired range, and as a result, the electrostatic attraction force is Strongly, the developer can be received and carried as desired and fed as desired, so that a high quality image can be formed.

  The common logarithm of the volume resistivity and the common logarithm of the surface resistivity of the elastic layer 3 can be obtained in the same manner as the common logarithm of the volume resistivity and the common logarithm of the surface resistivity of the endless belt substrate 2. The common logarithm of the volume resistivity and the common logarithm of the surface resistivity of the elastic layer 3 are, for example, depending on the type and / or content of the ionic conductive agent contained in the rubber composition to be described later that forms the elastic layer 3. Can be adjusted.

  The elastic layer 3 preferably has elasticity. For example, the elastic layer 3 generally has a JIS A hardness of 10 to 80, more preferably 20 to 60. Particularly preferred. When the elastic layer 3 has a JIS A hardness within the above range, a large contact width between the endless belt 1 and the member with which the endless belt 1 contacts can be secured, and as a result, the elastic layer 3 is supported by the member. While almost all of the developer can be received and carried, almost all of the developer carried by the endless belt 1 can be supplied to other members. Therefore, when the elastic layer 3 has a JIS A hardness within the above range, when the endless belt 1 is used, high transferability of the developer can be realized. The JIS A hardness of the elastic layer 3 can be measured according to JIS K6301.

  The elastic layer 3 contains at least one ionic conductive agent selected from the group consisting of organic boron complex salts, ionic liquids, and alkali metal perchlorates. If the elastic layer 3 contains the ionic conductive agent, even if the surrounding environment where the endless belt 1 is mounted changes to a high temperature and high humidity environment, the elastic layer 3 has substantially constant electrical characteristics, particularly resistivity. In addition, the ionic conductive agent contained therein is less likely to migrate to the elastic layer surface.

  The organic boron complex salt may be a salt having an ion of an organic boron complex as an anion and an ion of an alkali metal element as a cation. The organoboron complex can be used without any particular limitation, and examples thereof include borobis (1,1-diphenyl-1-oxo-acetyl ion). Examples of the alkali metal element include lithium, sodium, potassium, and the like. As the organic boron complex salt, a complex salt obtained by arbitrarily combining ions of the organic boron complex and ions of the alkali metal element can be used without any particular limitation. Examples of the organic boron complex salt include borobis (1,1-diphenyl-1-oxo-acetyl) potassium salt (for example, trade name “LR-147”, manufactured by Nippon Carlit Co., Ltd.).

  The organic boron complex salt is borobis (1,1-diphenyl-1-oxo-acetyl) potassium salt, which is uniformly dispersed in a rubber composition to be described later that forms the elastic layer 3, whereby the surface of the elastic layer 3 It is preferable in that the volume resistivity and the surface resistivity of the elastic layer 3 can be adjusted within the above ranges.

  The ionic liquid can be used without particular limitation as long as it is an ionic compound in a liquid state (for example, the viscosity is in the range of 20 to 500 mPa · s) at room temperature (25 ° C.). Examples of such ionic liquids include N-alkyl-3-alkylpyridinium bistrifluoromethanesulfonylimide, 1-alkyl-3-alkylimidazolium trifluoromethanesulfonylimide, 1-alkyl-3-alkylpyridine- Examples thereof include 1-ium trifluoromethanesulfonate. These alkyl groups are preferably each independently an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group.

Examples of the N-alkyl-3-alkylpyridinium bistrifluoromethanesulfonylimide include, for example, N-butyl-3-methylpyridinium bistrifluoromethanesulfonylimide (chemical formula C ₁₂ H ₁₆ F ₆ N ₂ O ₄ S ₂ , product name “CIL-312” manufactured by Nippon Carlit Co., Ltd.). Examples of the 1-alkyl-3-alkylimidazolium trifluoromethanesulfonylimide include 1-ethyl-3-methylimidazolium trifluoromethanesulfonylimide (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 1-butyl-3- And methyl imidazolium trifluoromethanesulfonylimide (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). Examples of the 1-alkyl-3-alkylpyridine-1-ium trifluoromethanesulfonate include 1-butyl-3-methylpyridine-1-iumtrifluoromethanesulfonate (chemical formula C ₁₁ H ₁₆ F ₃ NO ₃ S Product name “CIL-313”, manufactured by Nippon Carlit Co., Ltd.) and the like.

  Among these, ionic liquids include 1-ethyl-3-methylimidazolium trifluoromethanesulfonylimide, 1-butyl-3-methylimidazolium trifluoromethanesulfonylimide, N-butyl-3-methylpyridinium bistrifluoro Methanesulfonylimide, 1-butyl-3-methylpyridine-1-ium trifluoromethanesulfonate, is uniformly dispersed in a rubber composition to be described later which forms the elastic layer 3, thereby forming a surface on the elastic layer 3. This is preferable in that it is difficult to shift to a high degree and the volume resistivity and surface resistivity of the elastic layer 3 can be adjusted within the above ranges.

  The alkali metal perchlorate may be a salt of an alkali metal ion and a perchlorate ion. Preferred examples of the alkali metal element include lithium, sodium, and potassium, and particularly preferred is lithium. As the alkali metal perchlorate, a salt formed by arbitrarily combining ions of the alkali metal element and perchlorate ions can be used without any particular limitation. Examples of the alkali metal perchlorate include lithium perchlorate, sodium perchlorate, and potassium perchlorate.

  Among these, the alkali metal perchlorate, lithium perchlorate, is highly dispersed on the surface of the elastic layer 3 by being uniformly dispersed in a rubber composition to be described later that forms the elastic layer 3. This is preferable because the volume resistivity and the surface resistivity of the elastic layer 3 can be adjusted within the above ranges.

  At least one of these organic boron complex salts, ionic liquids, and alkali metal perchlorates is selected and contained in the elastic layer 3 as an ionic conductive agent. In general, the content of the ionic conductive agent in the elastic layer 3 is preferably 0.05 to 30 parts by mass and 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber forming the elastic layer 3. Is more preferable, and 0.15 to 7 parts by mass is particularly preferable. When the content of the ionic conductive agent is within the above range, the electrical properties such as volume resistivity and surface resistivity of the elastic layer 3 can be adjusted to a desired range that is not affected by environmental changes. In addition, the ionic conductive agent is more difficult to migrate to the surface of the elastic layer 3, and the physical properties of the elastic layer 3 and the endless belt 1 due to the large amount of ionic conductive agent contained are not greatly reduced.

  Conventional ionic conductive agents such as quaternary ammonium salts, phosphate esters, aliphatic alcohol sulfate salts and amine perchlorates, which have been often used as an ionic conductive agent in the elastic layer of an endless belt, If it is contained in the elastic layer, these ionic conductive agents may move to the surface of the elastic layer due to changes in the surrounding environment of the endless belt, and may contaminate the contact body of the endless belt. In some cases, the electrical characteristics are not uniform and fluctuate greatly to receive and carry the developer and / or supply the carried developer to other members as desired. However, the inventors use, among ionic conductive agents, novel organoboron complex salts, ionic liquids, and alkali metal perchlorates that have not been used for elastic layers of endless belts until now. An endless belt 1 in which an elastic layer 3 containing at least one ionic conductive agent selected from the group consisting of organic boron complex salts, ionic liquids and alkali metal perchlorates is formed on an image forming apparatus. In this case, even if the surrounding environment of the endless belt 1 is changed, the organic boron complex salt, the ionic liquid, and the perchlorate of the alkali metal hardly move to the surface of the elastic layer 3, and the elastic layer 3 is stabilized. The present invention was completed by newly discovering that electrical characteristics such as resistivity are exhibited.

  Therefore, the present invention provides the elastic layer 3 with at least one selected from the group consisting of these organic boron complex salts, ionic liquids, and alkali metal perchlorates as an ionic conductive agent for adjusting electrical characteristics. One of the characteristics is to contain them. When the elastic layer 3 contains at least one ionic conductive agent selected from the group consisting of these organoboron complex salts, ionic liquids, and alkali metal perchlorates, the volume resistivity and surface resistance of the elastic layer 3 The rate can be adjusted to a stable value within a desired range, and the organic boron complex salt, ionic liquid, and alkali metal perchlorate hardly migrate to the surface of the elastic layer 3.

  The elastic layer 3 is formed by curing rubber and a rubber composition containing the ionic conductive agent. The rubber contained in the rubber composition is silicone rubber 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. Examples thereof include rubber, butyl rubber, epichlorohydrin rubber, urethane rubber, and fluorine rubber. The ionic conductive agent contained in the rubber composition is the same as the ionic conductive agent. The content of the ionic conductive agent in the rubber composition is adjusted so as to be the content of the ionic conductive agent in the elastic layer 3 with respect to 100 parts by mass of the rubber contained in the rubber composition. It is adjusted to the same range as the content of the ionic conductive agent in the layer 3.

  The rubber composition may contain various additives usually contained in the rubber composition as long as the object of the present invention is not impaired. Examples of the various additives include vulcanizing agents and vulcanization accelerators. , Vulcanization accelerator, Vulcanization retarder, Dispersant, Foaming agent, Anti-aging agent, Antioxidant, Filler, Pigment, Colorant, Processing aid, Softener, Plasticizer, Emulsifier, Curing agent, Heat resistance Examples thereof include a property improver, a flame retardant improver, an acid acceptor, a thermal conductivity improver, a release agent, and a solvent. These various additives may be commonly used additives or may be specially used additives depending on applications.

  The rubber composition is prepared by mixing an ionic conductive agent and rubber and optionally various additives by a known method. Known methods include, for example, a mixing method using a mixing roll, a pressure kneader, an extruder, a triple roll, a homogenizer, a ball mill, a pot mill, a bead mill, and the like. For example, in the rubber composition, the rubber and / or rubber forming components such as monomers or prepolymers forming the rubber are dissolved in a solvent such as ethyl acetate, and an ionic conductive agent and various desired additives are added to the solution. Can be prepared by mixing uniformly at room temperature or under heating.

  The endless belt 1 having a two-layer structure including the endless belt base 2 and the elastic layer 3 is set to a desired width and inner peripheral diameter according to the use of the endless belt 1 and the like. For example, the endless belt 1 has a width of 200 to 350 mm and an inner peripheral diameter of 200 to 2,500 mm. Moreover, although the whole thickness of the endless belt 1 is not specifically limited, Usually, it is preferable that it is 0.03-1 mm, for example, it is more preferable that it is 0.05-0.2 mm, and 0.07-0. It is particularly preferably about 14 mm. When the thickness of the endless belt 1 is within the above range, mechanical strength and flexibility can be ensured, and the durability is excellent. The thickness of the endless belt 1 is measured in the same manner as the endless belt substrate 2.

  The endless belt 1 usually has a common logarithmic value of volume resistivity (unit: Ω · cm) preferably in the range of 6 to 14, and particularly preferably in the range of 8 to 12. When the endless belt 1 has a common logarithmic value of the volume resistivity in the above range, the electrostatic adsorption force is strong, and the developer can be supported and supplied as desired. Can be formed.

  The endless belt 1 usually has a common logarithmic value of surface resistivity (unit: Ω / □) preferably in the range of 8 to 15, more preferably in the range of 9 to 14, and 9 to 13 It is particularly preferable to be within the range. When the endless belt 1 has a common logarithmic value of the surface resistivity in the above range, the electrostatic adsorption force is strong, and the developer can be carried and supplied as desired. Can be formed.

  The common logarithmic value of the volume resistivity and the common logarithm of the surface resistivity of the endless belt 1 can be obtained in the same manner as the common logarithm of the volume resistivity and the common logarithm of the surface resistivity of the endless belt substrate 2. The common logarithmic value of the volume resistivity of the endless belt 1 and the common logarithm of the surface resistivity are the common logarithm of the volume resistivity and the common logarithm of the surface resistivity of the endless belt substrate 2 and the volume resistance of the elastic layer 3. By appropriately adjusting the common logarithm value of the rate and the common logarithm value of the surface resistivity, it can be appropriately adjusted by a combination of the endless belt base 2 and the elastic layer 3 or the like.

Endless belt 1 having the above configuration, the temperature 10 ° C., the volume resistivity at a relative humidity of 20% of the low-temperature and low-humidity environment and the common logarithm of _{(ρv LL) (logρv LL)} , temperature 28 ° C., 80% relative humidity high temperature and high the difference between the volume resistivity at humidity environment common logarithm of _{(ρv HH) (logρv HH)} (logρv LL -logρv HH, hereinafter sometimes referred to as a volume resistivity difference.) is set to 0.9 or less . If this volume resistivity difference is 0.9 or less, the variation in volume resistivity due to changes in the surrounding environment is extremely small, and when the endless belt 1 is attached to the image forming apparatus, a high quality image is formed. To contribute. In particular, an endless belt for an image forming apparatus capable of forming a high-definition image that becomes a high-temperature and high-humidity environment by operation, and an image forming apparatus capable of forming a high-definition image at high speed. Even if 1 is used, an image having a desired quality can be formed. The volume resistivity difference is preferably 0.5 or less in that it can be particularly suitably used for such an image forming apparatus. The lower limit value of the volume resistivity difference is ideally 0, but is usually about 0.05.

Endless belt 1 having the above configuration, the temperature 10 ° C., the surface resistivity at a relative humidity of 20% of the low-temperature and low-humidity environment and the common logarithm of _{(ρs LL) (logρs LL)} , temperature 28 ° C., 80% relative humidity high temperature and high the difference between the surface resistivity at humidity environment common logarithm of _{(ρs HH) (logρs HH)} (logρs LL -logρs HH, hereinafter sometimes referred to as a surface resistivity difference.) is set to 0.8 or less . If the difference in surface resistivity is 0.8 or less, the variation in surface resistivity due to environmental changes in the surroundings is extremely small, and a high-quality image is formed when the endless belt 1 is attached to the image forming apparatus. To contribute. In particular, an endless belt for an image forming apparatus capable of forming a high-definition image that becomes a high-temperature and high-humidity environment by operation, and an image forming apparatus capable of forming a high-definition image at high speed. Even if 1 is used, an image having a desired quality can be formed. The surface resistivity difference is preferably 0.5 or less because it can be used particularly favorably in such an image forming apparatus. The lower limit value of the surface resistivity difference is ideally 0, but is usually about 0.05.

  Next, a method for manufacturing an endless belt according to the present invention will be described. In order to manufacture the endless belt according to the present invention, the resin composition for forming the endless belt base 2 and the rubber composition for forming the elastic layer 3 are respectively prepared as described above.

  Next, the prepared resin composition is formed into a ring shape by a known forming method to obtain an endless belt substrate 2. For example, when a thermoplastic resin is selected as the resin contained in the resin composition forming the endless belt 1, when a thermosetting resin is selected as the resin by centrifugal molding, extrusion molding, injection molding, or the like For example, the endless belt base 2 can be formed by centrifugal molding, RIM molding, or the like. Among these molding methods, centrifugal molding is preferable in that it can be applied regardless of the material and is excellent in thickness accuracy.

  When the endless belt base 2 is molded by centrifugal molding, the resin composition preferably has a viscosity at the molding adjusted to 50,000 mPa · s or less. When the viscosity exceeds 50,000 mPa · s, it may be difficult to produce the endless belt base 2 having a uniform thickness. The lower limit of the viscosity of the resin composition is not particularly limited, but is preferably 10 mPa · s or more. When the viscosity of the resin composition is out of the above range, the viscosity of the resin composition can be adjusted within the above range by adjusting the amount of the solvent added. As a solvent, the solvent used for the polycondensation reaction which synthesize | combines the said aromatic polyamideimide resin is mentioned.

  According to centrifugal molding, a resin composition that exhibits fluidity by containing a solvent is poured into a cylindrical mold, and the mold is rotated to form a resin composition layer on the inner peripheral surface of the mold by centrifugal force. The endless molded substrate is produced by uniformly spreading and drying and removing the solvent from the resin composition layer. Various metal pipes can be used for the mold. As a suitable mold, the inner peripheral surface of the mold is mirror-polished, and the inner peripheral surface that has become the mirror surface is subjected to a release treatment with a release agent such as a fluororesin or a silicone resin, and the formed endless base is formed. Examples thereof include a metal tube that can be easily removed from the inner peripheral surface.

  When a polyamideimide resin is selected as the resin contained in the resin composition, in addition to the above-described centrifugal molding, a polyamic acid obtained by partially polymerizing a tricarboxylic acid anhydride and a diisocyanate compound, which are raw materials of the polyamideimide resin, is used. Is applied to the inner and outer peripheral surfaces of the mold by a dipping method, a centrifugal method, a coating method, etc., or is developed into a cylindrical shape by an appropriate method such as filling the casting mold with the polyamic acid solution. The developed layer is dried to form a belt shape, and the molded product is heat-treated to convert the polyamic acid to an imide and recover from the mold (Japanese Patent Laid-Open No. 61-95361, The endless belt base 2 can also be manufactured according to Japanese Patent Application Laid-Open No. 64-22514 and Japanese Patent Application Laid-Open No. 3-180309.

  The solvent is removed from the layer of the resin composition developed on the inner peripheral surface of the mold to produce an endless molded substrate. Here, the solvent to be removed is a solvent contained in the layer of the resin composition developed on the inner peripheral surface of the mold. For example, in addition to the solvent used when adjusting the viscosity of the resin composition And a solvent used when synthesizing the aromatic polyamideimide resin. Examples of the treatment for removing the solvent from the resin composition layer developed on the inner peripheral surface of the mold include a heat treatment. To remove the solvent, the following primary solvent removal step and secondary solvent removal step are used. It is preferable to perform a solvent removal treatment consisting of

  In the primary solvent removing step, molding is performed while removing the solvent from the resin composition layer developed on the inner peripheral surface of the mold by rotating the mold, and the resin composition layer is used as a film-shaped molded body. In the primary solvent removal step, the solvent is removed by passing hot air of 40 to 150 ° C. through the mold for 5 to 60 minutes while rotating the mold. When the hot air temperature exceeds 150 ° C. and / or when the heating time exceeds 60 minutes, the molded film-like molded body may be oxidized.

  In the secondary solvent removing step, the film-like molded body formed in the primary solvent removing step is taken out from the centrifugal molding machine together with the mold, heated together with the mold to remove the solvent from the film-shaped molded body, To do. For example, when using a heater such as a hot air dryer or oven, the film-like molded body may be heated together with the mold at 200 to 300 ° C. for 1 to 3 hours, and when a superheated steam furnace is used. What is necessary is just to heat a film-like molded object for 0.5 to 3 hours with 200-260 degreeC superheated steam with a metal mold | die. In addition, if a deformation | transformation etc. of a film molded object can be prevented, a film molded object can be demolded from a metal mold | die, and a film molded object can also be heated on the said conditions.

  After producing an endless molded substrate from which the solvent has been removed in this manner, the endless molded substrate is taken out of the mold and allowed to cool. When the endless molded substrate is allowed to cool together with the mold, the endless molded substrate can be removed due to the difference in thermal expansion coefficient between the mold and the endless molded substrate.

  In this way, the endless molded substrate is removed from the mold, both end portions of the annular endless molded substrate are removed, and the endless belt substrate 2 is manufactured by cutting to a predetermined width. The cutting machine that cuts the endless molded substrate may be an apparatus that can cut the endless molded substrate so that the cutting start point and the cutting end point substantially coincide with each other.

  The elastic layer 3 is formed on the outer peripheral surface of the endless belt base 2 manufactured in this way. That is, the elastic layer 3 is formed by curing a rubber composition containing at least one ionic conductive agent selected from the group consisting of an organic boron complex salt, an ionic liquid, and an alkali metal perchlorate. In order to form the elastic layer 3, for example, the following method is employed. First, the rubber composition is applied to the outer peripheral surface of the endless belt base 2. The rubber composition is applied by a normal application method, for example, a dipping method, a spray method, a roll coater method, a doctor blade coating method, etc., with a coating amount such that the thickness of the elastic layer 3 after curing falls within the above range, Applied. Next, the rubber composition applied to the outer peripheral surface of the endless belt base 2 is cured. As heating conditions, for example, heating conditions of 110 to 200 ° C. for 0.5 to 3 hours can be selected. The elastic layer 3 thus formed may have its surface polished or ground as desired.

  The endless belt 1 manufactured in this manner includes an elastic layer 3 containing at least one ionic conductive agent selected from the group consisting of an organic boron complex salt, an ionic liquid, and an alkali metal perchlorate. Therefore, it has electrical characteristics of the semiconductive region, and has, for example, a volume resistivity difference of 0.9 or less and / or a surface resistivity difference of 0.8 or less. That is, the endless belt 1 has substantially constant electrical characteristics, particularly resistivity, even if the surrounding environment where the endless belt 1 is attached changes to a high temperature and high humidity environment. Further, since the endless belt 1 contains a specific ionic conductive agent, the ionic conductive agent hardly transfers to the surface of the elastic layer 3. Therefore, the endless belt 1 has small variations in volume resistivity and surface resistivity even when the environment changes, and can prevent contamination of the abutting member.

  Since the endless belt 1 has such characteristics, when it is attached to the image forming apparatus, it can contribute to forming a high-quality image. In particular, an image forming apparatus capable of forming a high-definition image that becomes a high-temperature and high-humidity environment by operation, an image forming apparatus capable of forming an image at high speed, and a high-definition image at high speed When the image forming apparatus is mounted on an image forming apparatus that can form the image, it can sufficiently contribute to forming an image having a desired high quality.

  The endless belt according to the present invention is suitably used as an intermediate transfer belt mounted on an intermediate transfer type image forming apparatus. Since the endless belt according to the present invention has the above-described configuration, its use is not limited to the intermediate transfer belt, but is attached to a direct transfer type image forming apparatus and an intermediate transfer type image forming apparatus. Various endless belts, for example, a conveyance belt that conveys the recording medium, a transfer belt that contributes to the transfer of the developer to the recording medium, a transfer conveyance belt that conveys the recording medium and contributes to the transfer of the developer to the recording medium, and development It can also be used for a developing belt that supplies the developer to the image carrier, a transfer belt that fixes the developer transferred to the recording member, a photosensitive belt that carries the developer image, and the like.

  The endless belt according to the present invention is not limited to the above-described embodiments, and various modifications can be made within a range in which the object of the present invention can be achieved. For example, the endless belt base 2 and the elastic layer 3 of the endless belt 1 both have a single layer structure. In the present invention, the endless belt base and / or the elastic layer of the endless belt is a multilayer in which two or more layers are laminated. It may be a structure.

  In the endless belt 1, the elastic layer 3 is formed on the outer peripheral surface of the endless belt base 2. In the present invention, the adhesive layer or the primer layer is formed on the outer peripheral surface of the endless belt base 2. The elastic layer 3 may be formed on the outer peripheral surface of the adhesive layer or the primer layer. Further, the endless belt 1 includes an endless belt base 2 and an elastic layer 3. In this invention, the endless belt has a surface layer or the like formed of a fluororesin or the like on the outer peripheral surface of the elastic layer as desired. You may have, and fine particles, such as a fluororesin, may adhere to the outer peripheral surface of an elastic layer.

  Further, the endless belt 1 includes an endless belt base 2 and an elastic layer 3. In the present invention, the endless belt is an inner peripheral surface of the endless belt base and, in the axial direction of the endless belt base, as desired. At least one end may be provided with a string-like or belt-like elongated guide member formed of an elastic material. This guide member functions as a guide for preventing side shake while the endless belt is running. Examples of the material for the guide member include elastic materials having appropriate rubber elasticity and wear resistance, such as urethane elastomers, silicone elastomers, fluororesin elastomers, and styrene elastomers. Among these, urethane-based elastomers having an A hardness of 30 or more and 95 or less according to JIS K 6253-1997, which is excellent in wear resistance, are preferable. Preferably, the guide member is provided so as to go around the inner peripheral surface of the endless belt base at both ends in the axial direction of the endless belt base.

  Next, an example of an image forming apparatus provided with the endless belt 1 according to the present invention (hereinafter sometimes referred to as an image forming apparatus according to the present invention) will be described with reference to FIG. The image forming apparatus 10 is an intermediate transfer type tandem color image forming apparatus. An intermediate transfer tandem color image forming apparatus 10 is basically configured in the same manner as a conventionally known image forming apparatus, but an endless belt 1 according to the present invention is mounted as an intermediate transfer belt 1.

  As shown in FIG. 2, the endless belt 1 is stretched around two support rollers 42, a tension roller 43 and a counter roller 44 as the intermediate transfer belt 1. In the vicinity of the position where the counter roller 44 is installed, a secondary transfer unit 40 including a counter roller 44, a secondary transfer roller 45, and an electrode roller 46 is disposed.

  As shown in FIG. 2, in the image forming apparatus 10, four types of developing units B, C, M, and Y are arranged in series on the intermediate transfer belt 1. The developing unit B includes an image carrier 11B such as a photoconductor, a charging roller 12B, an exposure unit 13B, a developing roller 23B, a developing unit 20B including a housing 21B, a transfer roller 14B, and a cleaning blade 15B. The developing unit B contains a black developer. The developing units C, M, and Y are configured in the same manner as the developing unit B, and contain a cyan developer 22C, a magenta developer 22M, and a yellow developer 22Y.

  As shown in FIG. 2, a fixing unit 30 having an endless belt 35 as a fixing belt is disposed downstream in the conveyance direction of the recording medium 16 in the image forming apparatus 10. The fixing device 30 is a pressure heat fixing device including a fixing roller 31, a support roller 33, a fixing belt 35, and a pressure roller 32 in a housing 34 having an opening. The fixing unit 30 may be a heat roller fixing device, a heat fixing device, a pressure fixing device, or the like.

  The image forming apparatus 10 forms an image as follows. First, the developing unit B visualizes the electrostatic latent image on the surface of the image carrier 11B as a developer image with the black developer 22B, and the developer image is transferred onto the intermediate transfer belt 1 (primary transfer). Subsequently, the developer images are transferred to the intermediate transfer belt 1 by the developing units C, M, and Y, and a color image is formed. The color image reaches the secondary transfer unit 40 by the rotation of the intermediate transfer belt 1 and is transferred onto the recording medium 16 conveyed to the secondary transfer unit 40 (secondary transfer). Next, the recording medium 16 in which the color image is visualized is conveyed to the fixing unit 30 and the color image is fixed as a permanent image. In this way, a color image is formed on the recording medium 16. Although the case where a color image is formed using the image forming apparatus 10 has been described, in the case of forming a monochrome image, the developer image primary-transferred to the intermediate transfer belt 1 is immediately secondary-transferred to the recording medium 16. Then, it may be conveyed to the fixing means 30.

  Another example of an image forming apparatus provided with the endless belt 1 according to the present invention (hereinafter sometimes referred to as an image forming apparatus according to the present invention) will be described with reference to FIG. The image forming apparatus 50 is an intermediate transfer type multi-pass color image forming apparatus. The intermediate transfer type multi-pass color image forming apparatus 50 is basically configured in the same manner as a conventionally known image forming apparatus, but an endless belt 1 according to the present invention is mounted as the intermediate transfer belt 1.

  As shown in FIG. 3, the endless belt 1 is stretched around two support rollers 42, a tension roller 43 and a counter roller 44 as the intermediate transfer belt 1. In the vicinity of the position where the counter roller 44 is installed, a secondary transfer unit 40 including a counter roller 44, a secondary transfer roller 45, and an electrode roller 46 is disposed.

  As shown in FIG. 3, the image forming apparatus 50 includes a developing unit 20 including four types of developing units B, C, M, and Y. The developing units B, C, M, and Y built in the developing unit 20 include a charging unit, an exposure unit, and the like, and store a black developer, a cyan developer, a magenta developer, and a yellow developer, respectively. The developing unit 20 may include a charging unit, an exposing unit, and the like outside the developing unit 20 and in the vicinity of the image carrier 11.

  As shown in FIG. 3, a fixing unit 30 is disposed downstream in the conveyance direction of the recording body 16 in the image forming apparatus 50. The fixing device 30 is configured in the same manner as the fixing device 30 of the image forming apparatus 10.

  The image forming apparatus 50 forms an image as follows. First, an electrostatic latent image is visualized as a developer image with the black developer 22B on the surface of the image carrier 11 by the developing unit B of the developing means 20, and transferred onto the intermediate transfer belt 1 (primary transfer). Subsequently, the image carrier 11 and the intermediate transfer belt 1 rotate once, and each developer image is superimposed and transferred to the intermediate transfer belt 1 by the developing units C, M, and Y, thereby forming a color image. The color image reaches the secondary transfer unit 40 by the rotation of the intermediate transfer belt 1 and is transferred onto the recording medium 16 conveyed to the secondary transfer unit 40 (secondary transfer). Next, the recording medium 16 in which the color image is visualized is conveyed to the fixing unit 30 and the color image is fixed as a permanent image. In this way, a color image is formed on the recording medium 16. Although the case where a color image is formed using the image forming apparatus 50 has been described, in the case of forming a monochrome image, the developer image primarily transferred to the intermediate transfer belt 1 is immediately secondary transferred to the recording medium 16. Then, it may be conveyed to the fixing means 30.

  According to these image forming apparatuses 10 and 50, since the endless belt 1 is used as the intermediate transfer belt 1, even if the environment around the endless belt 1 changes, the endless belt 1 has a small variation in resistivity. , The contact member is hardly contaminated. Therefore, these image forming apparatuses 10 and 50 can form a high-quality image even if the image is highly defined and / or the image forming speed is increased.

  The image forming apparatus according to the present invention is not limited to the above-described example, and various modifications can be made within a range in which the object of the present invention can be achieved. For example, the image forming apparatuses 10 and 50 are electrophotographic image forming apparatuses. However, in the present invention, the image forming apparatus is not limited to the electrophotographic system. For example, the electrostatic image forming apparatus. It may be. The image forming apparatuses 10 and 50 are intermediate transfer type image forming apparatuses. However, in the present invention, the image forming apparatus may be a direct transfer type image forming apparatus. It may be a tandem type image forming apparatus in which a plurality of image carriers having units are arranged in series on a transfer conveyance belt, or a monochrome type image forming apparatus having a single developing unit. The image forming apparatus according to the present invention is suitably used as an image forming apparatus such as a copying machine, a facsimile, or a printer.

Example 1
First, the endless belt base 2 was produced. That is, N-methyl-2-pyrrolidone, trimellitic anhydride, an equivalent amount of diphenylmethane-4,4′-diisocyanate, and reaction raw materials (trimellitic anhydride and diphenylmethane-4,4) 2 mol% of potassium fluoride (catalyst) is added to the total number of moles of '-diisocyanate), the temperature is raised from room temperature to 150 ° C. over 30 minutes with stirring, and the temperature is maintained for 5 hours. An aromatic polyamideimide solution having an object concentration (substantially fully ring-closed polyamideimide resin) of 20% by mass was obtained. N-methyl-2-pyrrolidone was further added to this solution to prepare a polyamideimide solution having a reactant concentration of 15% by mass. To the obtained polyamideimide solution, an oxidation-treated carbon black (trade name “Printex 150T”, manufactured by Degussa, pH 4.0, volatile content 10.0%) is added to a total of 100 masses of the polyamideimide resin and the oxidation-treated carbon black. The resin composition was prepared by adding 18% by mass with respect to% and mixing and dispersing in a pot mill for 24 hours. The mold used for molding has an inner diameter of 226 mm, an outer diameter of 246 mm, and a length of 400 mm, and the inner surface of the mold is mirror-polished by polishing. Next, ring-shaped lids (inner diameter: 170 mm, outer diameter: 250 mm) are fitted into the openings at both ends of the mold, the mold is closed, and the resin composition is rotated at a speed of 1,000 rpm. 190 g was injected around the circumference. Next, the mold was rotated at the same speed for 30 minutes to uniformly develop the resin composition layer on the inner peripheral surface of the mold. Next, while rotating the mold at the same speed, the temperature around the mold was maintained at 80 ° C. with a hot air dryer, and this state was maintained for 30 minutes to form a film-shaped molded body. Thereafter, the rotation of the mold was stopped, the film-shaped molded body was taken out from the centrifugal molding machine together with the mold, subjected to superheated steam treatment in a superheated steam furnace adjusted to 250 ° C. for 2 hours, allowed to cool at room temperature, and endless. A molded substrate was obtained. The endless molded substrate was cooled together with the mold, the endless molded substrate was peeled off due to the difference in thermal expansion coefficient between the mold and the endless molded substrate, and the endless molded substrate was removed from the mold. Both end portions of the removed endless molded substrate were cut and cut into a size having a circumference of about 226 mm, a width of 240 mm, and a thickness of 100 μm to produce an endless belt substrate 2.

  A urethane solution having a solid content of 30% by mass (trade name “Nipporan 5120”, manufactured by Nippon Polyurethane Industry Co., Ltd.) was prepared. An organic boron complex salt “borobis (1,1-diphenyl-1-oxo-acetyl) potassium salt” (trade name “LR-147”, manufactured by Nippon Carlit Co., Ltd.) as an ionic conductive agent is added to the urethane solution. 1 part by mass (100 parts by mass with respect to 100 parts by mass of urethane) and 100 parts by mass of the curing agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) On the other hand, 10 parts by mass was added and stirred at room temperature for 10 minutes to prepare a rubber composition.

  Subsequently, this rubber composition was uniformly applied to the outer peripheral surface of the endless belt substrate 2 by a doctor blade coating method. The amount of the rubber composition applied was such that the thickness of the elastic layer 3 was 600 μm (in a non-dry state). The applied rubber composition was heated at 150 ° C. for 1 hour to form an elastic layer 3 having a thickness of 200 μm on the outer peripheral surface of the endless belt substrate 2. Thus, the endless belt of Example 1 was manufactured.

(Example 2)
Implementation was carried out in the same manner as in Example 1 except that the organic boron complex salt was changed to the ionic liquid “1-ethyl-3-methylimidazolium trifluoromethanesulfonylimide” (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). The endless belt of Example 2 was produced.
(Example 3)
The organic boron complex salt was changed to an ionic liquid “1-butyl-3-methylimidazolium trifluoromethanesulfonylimide” (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). 3 endless belts were produced.

Example 4
The organoboron complex salt is changed to an ionic liquid “N-butyl-3-methylpyridinium bistrifluoromethanesulfonylimide” (product name “CIL-312”, manufactured by Nippon Carlit Co., Ltd.), and the content of the urethane An endless belt of Example 4 was produced in the same manner as in Example 1, except that the amount was 0.16 parts by mass with respect to 100 parts by mass of the solution (0.53 parts by mass with respect to 100 parts by mass of urethane).
(Example 5)
The organoboron complex salt is changed to an ionic liquid “1-butyl-3-methylpyridine-1-ium trifluoromethanesulfonate” (product name “CIL-313”, manufactured by Nippon Carlit Co., Ltd.) The endless belt of Example 5 was manufactured in the same manner as in Example 1 except that 0.16 parts by mass was added to 100 parts by mass of the urethane solution (0.53 parts by mass with respect to 100 parts by mass of urethane). did.

(Example 6)
Except having changed content of the said organoboron complex salt into 0.7 mass part with respect to 100 mass parts of said urethane solutions (2.33 mass parts with respect to 100 mass parts of urethane), it carried out similarly to Example 1, and. Thus, an endless belt of Example 6 was produced.
(Example 7)
Except having changed content of the said organic boron complex salt into 5.6 mass parts (18.6 mass parts with respect to 100 mass parts of urethane) with respect to 100 mass parts of said urethane solutions, it is the same as that of Example 1. Thus, an endless belt of Example 7 was produced.

(Example 8)
Except for changing the oxidation-treated carbon black (trade name “Printex 150T”) of the endless belt base to (trade name “Special Black 4”, manufactured by Degussa Co., Ltd.) 8 endless belts were produced.

Example 9
The organoboron complex salt is changed to an alkali metal perchlorate “lithium perchlorate” (trade name “PEL100”, manufactured by Nippon Carlit Co., Ltd.), and the content is 9 mass relative to 100 mass parts of the urethane solution. The endless belt of Example 9 was manufactured in the same manner as in Example 1 except that the amount was 30 parts by mass (30 parts by mass with respect to 100 parts by mass of urethane).

(Comparative Example 1)
Except for changing the organoboron complex salt to tetrabutylammonium hydrogen sulfate (TBAHS) (manufactured by Wako Pure Chemical Industries, Ltd.), which is a quaternary ammonium salt described in Patent Document 1, as in Example 1, An endless belt of Comparative Example 1 was produced.
(Comparative Example 2)
An endless belt of Comparative Example 2 was produced in the same manner as in Example 1 except that the organic boron complex salt was changed to a quaternary ammonium salt “benzyltrimethylammonium chloride”.

(Comparative Example 3)
An endless belt of Comparative Example 2 was produced in the same manner as in Example 1 except that the organic boron complex salt was changed to a quaternary ammonium salt “tetramethylammonium chloride” (Fuji Junyaku Co., Ltd.).
(Comparative Example 4)
An endless belt of Comparative Example 2 was produced in the same manner as in Example 1 except that the organic boron complex salt was changed to a quaternary ammonium salt “tetraethylammonium bromide” (Fuji Junyaku Co., Ltd.).

  The common logarithm of the surface resistivity and the volume resistivity of each endless belt manufactured in this way are the low-temperature and low-humidity conditions of 10 ° C. and 20% relative humidity (“LL” in Tables 1 and 2). ), Normal conditions of a temperature of 23 ° C. and a relative humidity of 50% (indicated as “NN” in Tables 1 and 2), and a high temperature and high humidity of a temperature of 28 ° C. and a relative humidity of 80%. Under the conditions (denoted as “HH” in Tables 1 and 2), it was determined according to the above method. Further, in each endless belt, the volume resistivity difference between the common logarithmic value of the volume resistivity in the low temperature and low humidity environment and the common logarithm of the volume resistivity in the high temperature and high humidity environment, and the surface resistivity in the low temperature and low humidity environment The difference in surface resistivity between the common logarithmic value of and the common logarithmic value of the surface resistivity in the high temperature and high humidity environment was calculated. Furthermore, the common logarithmic value of the surface resistivity and the common logarithm of the volume resistivity of the endless belt substrate and the elastic layer of each endless belt conform to the above method under the low temperature and low humidity condition, the normal condition and the high temperature and high humidity condition, respectively. Asked. These measurement results are shown in Tables 1 and 2.

  Subsequently, the elastic layer 3 of each endless belt was cut out into 50 mm length x 50 mm width to prepare a test piece. The test piece was immersed in distilled water heated to 40 ° C. for 8 hours, and then taken out from the distilled water. After cooling the distilled water, the amount of ionic conductive agent or carbon black leached from the elastic layer 3 into the distilled water by liquid chromatography (adsorbent: silica gel, developing solvent: distilled water, flow rate: 1.0 ml / min) The amount was measured. This operation was performed on 10 specimens, and the arithmetic average value of the measured amount of ionic conductive agent or carbon black was used as the elution amount of each endless belt. The results are shown in Table 3.

<Real machine test>
Each endless belt was mounted as an intermediate transfer belt of an intermediate transfer tandem color image forming apparatus (trade name “DocuPrint C830”, manufactured by Fuji Xerox Co., Ltd.), and an image was printed under each environment. As a result, the surface of the recording medium printed with the endless belts of Examples 1 to 10 was not contaminated by the ionic conductive agent, but the recording body printed with the endless belts of Comparative Examples 1 to 4 was printed. Contamination due to the ion conductive agent was confirmed on the surface.

FIG. 1 is a schematic side view showing an endless belt which is an embodiment of an endless belt according to the present invention. FIG. 2 is a schematic view of a tandem type color image forming apparatus which is an example of the image forming apparatus according to the present invention. FIG. 3 is a schematic view of a multi-pass color image forming apparatus which is an example of the image forming apparatus according to the present invention.

Explanation of symbols

1 Endless belt (intermediate transfer belt)
2 Endless belt base 3 Elastic layer 10, 50 Image forming apparatus 11, 11B, 11C, 11M, 11Y Image carrier 12B, 12C, 12M, 12Y Charging means 13B, 13C, 13M, 13Y Exposure means 14, 14B, 14C, 14M , 14Y Transfer means 15B, 15C, 15M, 15Y Cleaning means 16 Recording medium 20, 20B, 20C, 20M, 20Y Developing means 21B, 21C, 21M, 21Y, 34 Housings 22B, 22C, 22M, 22Y Developers 23B, 23C , 23M, 23Y Developer carrier 30 Fixing device 31 Fixing roller 32 Pressure roller 33 Fixing belt support roller 35 Endless belt (fixing belt)
40 Secondary transfer section 42 Support roller 43 Tension roller 44 Opposite roller 45 Secondary transfer roller 46 Electrode rollers B, C, M, Y Development unit

Claims (2)

Comprising an endless belt base and an elastic layer formed on the endless belt base;
The endless belt, wherein the elastic layer contains at least one ionic conductive agent selected from the group consisting of an organic boron complex salt, an ionic liquid, and an alkali metal perchlorate.   An image forming apparatus comprising the endless belt according to claim 1.

Images