JP2006227119A - Endless belt for electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt for an electrophotographic apparatus with which biasing and meandering of the belt are prevented, the aggregation of foreign matter to an inner peripheral surface of the belt is averted and durability is excellent. <P>SOLUTION: The endless belt for the electrophotographic apparatus has at least a substrate 1. The substrate 1 is formed by using a denatured polyamide-imide resin prepared by copolymerizing the following (A) to (C). The coefficient of static friction on the inner peripheral surface of the substrate 1 is set in a range from 0.2 to 0.5 and the inner peripheral surface of the substrate 1 is provided with a guide 3 for meandering prevention made of a urethane-based elastomer of 70 to 90° in JIS-A hardness over the entire periphery of the opening edges at both right and left ends of the belt. (A) An aromatic isocyanate compound. (B) Anhydride of aromatic polyvalent carboxylic acid. (C) A silicone polymer having a polydimethyl siloxane structure in the molecule and having a reaction group with the isocyanate group of (A) at one terminal or both terminals. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an endless belt for an electrophotographic apparatus, and more specifically, an electrophotographic technology employing an electrophotographic technology such as a full color LBP (laser beam printer), a full color MFP (multifunction printer), a full color PPC (plain paper copier), or the like. In photographic equipment, the present invention relates to an endless belt for electrophotographic equipment used for an intermediate transfer belt, a paper transfer conveyance belt, and the like.

  In general, endless belts (seamless belts) are used for electrophotographic equipment employing electrophotographic technology such as full-color LBP, full-color MFP, full-color PPC, etc. It is used a lot. As such an endless belt, for example, a material in which a conductive carbon black is blended with a fluorine-based resin such as PVDF (polyvinylidene fluoride) and formed into a cylindrical film by a molding method such as a dipping method is used. It has been.

  However, although the fluororesin belt is excellent in electrical characteristics, it has the disadvantages that the physical properties of the belt such as the elastic modulus are lowered and the cost is increased.

  On the other hand, it has been proposed to use a semiconductive tubular polyamideimide in which carbon black is contained in a polyamideimide resin for a transfer belt for an image forming apparatus (see Patent Document 1). However, since the polyamide-imide resin described in Patent Document 1 has a rigid molecular structure, it has high rigidity. Therefore, a transfer belt for an image forming apparatus using such a polyamideimide resin has poor flex resistance and poor durability.

Conventionally, endless belts for electrophotographic equipment such as transfer belts have been positioned as consumables. However, endless belts for next-generation electrophotographic equipment have been demanded in order to reduce maintenance costs and reduce running costs of electrophotographic equipment. In particular, high durability is required. As means that have been taken to solve such problems, for example, a meandering prevention guide (tape) having a predetermined width is pasted over the entire periphery of the inner peripheral surface (back surface) of both ends of the endless belt. The technique which performs is proposed (refer patent document 2 and 3). In this way, the belt can be prevented from slipping or meandering, and the mechanical properties of the belt can be improved.
JP 2003-261768 A JP-A-10-198179 JP-A-7-187435

  However, while the endless belt is being used in the electrophotographic apparatus, the scattered toner, the wobbling guides such as the meandering prevention guide and the elastomer roller, and the sticking of the meandering prevention guide and the belt. Foreign substances such as those in which the pressure-sensitive adhesive used is dissolved may adhere to the inner peripheral surface of the belt and aggregate. When such agglomerates are sandwiched between the inner peripheral surface of the belt and a roller that stretches the belt, the belt is pushed up at that location, and cracks are likely to occur from the pushed-up belt location. Become.

  The present invention has been made in view of such circumstances, and prevents endless or meandering of the belt, and does not cause aggregation of foreign matters on the inner peripheral surface of the belt, and is endless for electrophotographic equipment having excellent durability. The purpose is to provide a belt.

In order to achieve the above object, an endless belt for electrophotographic equipment of the present invention is an endless belt for electrophotographic equipment comprising at least a base layer, and the base layer is a copolymer of the following (A) to (C): And the static friction coefficient of the inner peripheral surface of the base layer is set in the range of 0.2 to 0.5, and the openings on the left and right ends of the belt on the inner peripheral surface of the base layer are formed. The configuration is such that a meandering prevention guide made of urethane elastomer having a JIS-A hardness of 70 to 90 ° is provided over the entire periphery of the edge.
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.

  The inventors of the present invention have made extensive studies to solve the above problems. In the course of that research, we made a modified polyamideimide resin by copolymerizing an aromatic isocyanate compound, an aromatic polycarboxylic acid anhydride, and a specific silicone polymer, and using this modified polyamideimide resin If the base layer (base layer) of an endless belt for electrophotographic equipment is formed and the static friction coefficient of the inner peripheral surface of the base layer is set within a specific range, the durability will be improved and the drive performance of the belt will be improved. It has been found that the agglomeration of foreign matter on the inner peripheral surface of the belt can be suppressed without impairing the belt. Furthermore, as a result of repeated research on the meandering prevention guide formed over the entire circumference of the opening at both ends of the inner peripheral surface of the endless belt (base inner peripheral surface), a guide made of urethane elastomer having a specific hardness is obtained. As a result, it was found that the intended purpose can be achieved because of excellent wear resistance and the like, and generation of wear debris can be suppressed, and the present invention has been achieved.

  Thus, the endless belt for electrophotographic equipment of the present invention is an endless belt consisting of a single layer consisting of only a base layer or two or more layers including a base layer, at least the base layer of which is a specific modified polyamideimide resin Furthermore, the static friction coefficient of the inner peripheral surface of the base layer is set to a specific range, and the urethane system having a specific hardness is provided over the entire periphery of the opening edge at the left and right ends of the belt on the inner peripheral surface of the base layer. An elastomer meandering prevention guide is provided. Therefore, the endless belt of the present invention is excellent in durability, can prevent the belt from slipping and meandering, and is also free of foreign matter (abrasion debris such as a meandering prevention guide, scattered toner, etc.) on the inner peripheral surface of the belt. Since aggregation is difficult to occur, various problems caused by these aggregates (such as occurrence of cracks in the belt) are solved.

  In particular, when the adhesion between the base layer and the guide for preventing meandering is made with a reaction curable adhesive belonging to any of epoxy resin, urethane resin, and modified silicone resin, elution after the adhesion occurs. It does not occur, and various problems caused by the aggregate of the eluate (such as generation of cracks in the belt) are solved.

  Next, an embodiment of the present invention will be described.

  The endless belt for an electrophotographic apparatus of the present invention is configured, for example, by directly forming the surface layer 2 on the outer peripheral surface of the base layer 1 as shown in FIG. 1, and the left and right sides of the endless belt on the inner peripheral surface of the base layer 1. A meandering prevention guide 3 is provided over the entire circumference of the opening edge at both ends. FIG. 2 is a partial cross-sectional view of the endless belt when cut in the vicinity of the center thereof.

In the present invention, the base layer 1 is formed using a modified polyamideimide (PAI) resin obtained by copolymerizing (reacting) the following (A) to (C): The static friction coefficient is set in a range of 0.2 to 0.5, and the meandering prevention guide 3 is formed of a urethane elastomer having a JIS-A hardness of 70 to 90 °.
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.

  The aromatic isocyanate compound (A) used for forming the modified polyamideimide (PAI) resin is not particularly limited as long as it is a compound having an aromatic ring in the molecule. For example, diphenylmethane diisocyanate (MDI) , Toluene diisocyanate (TDI), tolidine diisocyanate (TODI), xylylene diisocyanate (XDI), lysine diisocyanate (LDI), naphthalene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tetramethylxylene diisocyanate (TMXDI) and the like. . These may be used alone or in combination of two or more. Among these, MDI and TODI are preferably used in terms of reactivity, cost, and solubility.

  The anhydride of the aromatic polycarboxylic acid (B) is not particularly limited as long as it has an aromatic ring in the molecule and undergoes a condensation reaction with the aromatic isocyanate compound (A). Examples thereof include aromatic polyvalent carboxylic acid anhydride (B1) and aromatic polyvalent carboxylic acid dianhydride (B2). These may be used alone or in combination of two or more. In the present invention, an aromatic polyvalent carboxylic acid may be used in combination with the anhydride (B) of the aromatic polyvalent carboxylic acid.

  Examples of the aromatic polycarboxylic anhydride (B1) include trimellitic anhydride (trimellitic anhydride), naphthalene-1,2,4-tricarboxylic anhydride, and the like. These may be used alone or in combination of two or more. Among these, trimellitic anhydride (trimellitic anhydride) is preferably used in terms of reactivity, cost, solubility, and the like.

  Examples of the aromatic polycarboxylic dianhydride (B2) include benzene-1,2,4,5-tetracarboxylic dianhydride (pyromellitic dianhydride), benzophenone-3, 3 ', 4,4'-tetracarboxylic dianhydride, diphenyl ether-3,3', 4,4'-tetracarboxylic dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride , Biphenyl-3,3 ', 4,4'-tetracarboxylic dianhydride, biphenyl-2,2', 3,3'-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetra Carboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5 8-tetracarboxylic dianhydride, , 8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8 -Tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8- Tetracarboxylic dianhydride, phenanthrene-1,3,9,10-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) ) Methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4- Dicarboxyphenyl) ethane dianhydride 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,3-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydrides, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylene glycol bis (anhydro trimellitate), propylene glycol bis (anhydro trimellitate) and the like can be mentioned. These may be used alone or in combination of two or more. Among these, ethylene glycol bis (anhydrotrimellitate) is preferably used in terms of reactivity, cost, solubility, and the like.

  As the aromatic polycarboxylic acid anhydride (B) in the present invention, the aromatic polycarboxylic acid anhydride (B1) and the aromatic polycarboxylic acid dianhydride (B2) are used in combination. And preferably used. Thus, when B1 and B2 are used in combination, the ratio of the imide group in the modified PAI resin is increased, so that the water absorption is reduced and the bending of the endless belt can be improved.

  The molar mixing ratio of B1 and B2 is preferably within a range of B1 / B2 = 90/10 to 50/50, and particularly preferably within a range of B1 / B2 = 80/20 to 60/40. It is preferable to use B1 and B2 in such a ratio because the bending wrinkles can be improved without deteriorating the bending resistance.

  Next, the specific silicone polymer (C) used together with the above (A) and (B) is a silicone polymer having a polydimethylsiloxane structure in the molecule, and at one end or both ends, the above-mentioned (A) There is no particular limitation as long as it has a reactive group for the isocyanate group, and examples thereof include one having one reactive group at both ends, or one having two reactive groups at one end.

  The polydimethylsiloxane structure is a structure in which a structural unit represented by the following general formula (1) is a repeating unit.

  The reactive group is not particularly limited as long as it is a functional group that reacts with the isocyanate group of the aromatic isocyanate compound (A), and examples thereof include a hydroxyl group, a carboxyl group, and an amino group.

  As the silicone polymer having a reactive group at both ends, specifically, a carboxylic acid both-end silicone polymer having one carboxyl group at both ends (Toray Dow Corning Silicone, BY16-750), Examples thereof include a silicone polymer having hydroxyl groups at both ends (SF8427, manufactured by Toray Dow Corning Silicone).

  The silicone polymer having two reactive groups at one end is specifically a one-end bifunctional silicone polymer having two hydroxyl groups at one end (Shin-Etsu Chemical Co., Ltd., X-22-176DX). Etc.

  The acid value of the specific silicone polymer (C) is preferably in the range of 1 to 1000 mgKOH / g, particularly preferably in the range of 4 to 150 mgKOH / g.

  The number average molecular weight (Mn) of the specific silicone polymer (C) is preferably in the range of 200 to 40,000, particularly preferably in the range of 1,000 to 20,000.

  The blending ratio of the specific silicone polymer (C) is the total amount of the above (A) to (C) [In addition, as described later, when the carboxylic acid both-end polymer (D) is used, (A) to The total amount of (D) is preferably in the range of 1 to 20% by weight, particularly preferably in the range of 2 to 15% by weight. That is, if the blending ratio of the specific silicone polymer (C) is less than 1% by weight, the friction coefficient does not decrease, so that foreign matter agglomeration cannot be suppressed. This is because the belt is lowered too much and the belt is idle with respect to the driving roller.

  In addition, the modified polyamideimide resin used in the present invention may be a copolymer obtained by copolymerizing the carboxylic acid terminal polymer (D) together with the above (A) to (C). The carboxylic acid both-end polymer (D) is not particularly limited as long as it has one carboxylic acid at each end of the polymer. Examples thereof include carboxylic acid both-end polybutadiene, carboxylic acid both-end hydrogenated polybutadiene, and carboxylic acid. Examples thereof include polyesters at both ends, polyamides at both ends of carboxylic acid, and polyacrylonitrile-butadiene copolymers at both ends of carboxylic acid. These may be used alone or in combination of two or more.

  The carboxylic acid used for introducing the carboxylic acid into both ends of the polymer is not particularly limited, and examples thereof include aliphatic carboxylic acids and aromatic carboxylic acids. These may be used alone or in combination of two or more.

  Examples of the aliphatic carboxylic acid include adipic acid, sebacic acid, suberic acid, oxalic acid, succinic acid, corkic acid, azelaic acid, dodecanedicarboxylic acid, undecanedicarboxylic acid, maleic acid, fumaric acid, itaconic acid and the like. It is done. Examples of the aromatic carboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, chlorophthalic acid, and nitrophthalic acid.

  The said carboxylic acid both terminal polymer (D) can be obtained by introduce | transducing the above carboxylic acid into the both terminal of polymers, such as polybutadiene, hydrogenated polybutadiene, polyester, and polyamide which were synthesize | combined according to the normal manufacturing method. The method for synthesizing the polymer such as polybutadiene, hydrogenated polybutadiene, polyester, and polyamide is not particularly limited. For example, polyesters and polyamides are described in pages 208 to 231 and pages 252 to 287 of 4th edition Experimental Chemistry Course 28 Polymer Synthesis (edited by the Chemical Society of Japan, 1992, published by Maruzen Co., Ltd.). It can be produced according to the method.

  Of the carboxylic acid both-end polymer (D), the carboxylic acid both-end polyester can be prepared, for example, as follows. That is, in a reaction vessel equipped with a heating device, a stirring device, a reflux device, a water separator, a distillation column and a thermometer, a dicarboxylic acid such as adipic acid or sebacic acid, methylpentanediol, nonanediol, methyloctanediol, etc. A diol is charged, and the temperature is raised to a predetermined temperature (for example, 220 ° C.) over a predetermined time (for example, 1 hour). Furthermore, after continuing the polycondensation reaction at a predetermined temperature (for example, 220 ° C.), the desired carboxylic acid-terminated polyester can be obtained by cooling to a predetermined temperature (for example, room temperature).

  In addition, carboxylic acid both terminal polymer (D), such as carboxylic acid both terminal polybutadiene, can also be produced according to the said manufacturing method.

  The acid value of the carboxylic acid both-end polymer (D) is preferably in the range of 15 to 150 mgKOH / g, particularly preferably in the range of 45 to 110 mgKOH / g.

  Moreover, the number average molecular weight (Mn) of the said carboxylic acid both terminal polymer (D) has the preferable inside of the range of 750-7500, Most preferably, it exists in the range of 1000-2500.

  The blending ratio of the carboxylic acid both terminal polymer (D) is preferably in the range of 5 to 50% by weight, particularly preferably in the range of 10 to 30% by weight of the total amount of the above (A) to (D). is there. That is, when the blending ratio of the carboxylic acid both terminal polymers (D) is less than 5% by weight, the durability tends to be deteriorated, whereas when it exceeds 50% by weight, the creep rate tends to be deteriorated. Because.

  Here, the total number of moles of the isocyanate group of the aromatic isocyanate compound (A) (a) and the total number of moles of the acid anhydride group and the carboxyl group of the anhydride of the aromatic polyvalent carboxylic acid (B) ( The molar mixing ratio of b) and the total number of moles (d) of the carboxyl groups of the carboxylic acid both-end polymer (D) with the total number of moles [(b) + (d)] is (a) / [(b ) + (D)] = 90/100 to 130/100 is preferable, and (a) / [(b) + (d)] = 100/100 to 120/100 is particularly preferable. That is, when the value of (a) / [(b) + (d)] is out of the upper limit or lower limit, it is difficult to increase the molecular weight of the PAI resin, and the durability tends to deteriorate. Because.

  Next, the modified PAI resin can be prepared, for example, as follows. That is, a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube was prepared, and the aromatic isocyanate compound (A) and an anhydride of an aromatic polycarboxylic acid such as trimellitic anhydride ( B), a specific silicone polymer (C), and, if necessary, a carboxylic acid both terminal polymer (D) are blended in a predetermined amount, and N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide ( DMF), N, N-dimethylacetamide (DMAC), γ-butyrolactone, and other polar solvents are charged and stirred for a predetermined time (preferably 1 to 3 hours) under a nitrogen stream with a predetermined temperature (preferably 130). To 150 ° C). Next, the modified PAI resin can be prepared by reacting at a predetermined temperature (preferably 130 to 150 ° C.) for a predetermined time (preferably about 3 to 5 hours) and then stopping the reaction.

  The modified PAI resin thus obtained preferably has a number average molecular weight (Mn) in the range of 5,000 to 100,000, particularly preferably Mn in the range of 10,000 to 50,000. That is, if the Mn of the PAI resin is less than 5,000, the tear strength is lowered and the durability is deteriorated. Conversely, if the Mn of the PAI resin exceeds 100,000, the solution viscosity is increased and the workability is deteriorated. This is because the tendency to do is seen. The number average molecular weight (Mn) can be measured by a gel permeation chromatograph (GPC) method.

  In addition, as a material (material for base layers) used for formation of the said base layer 1, a conductive filler, a phosphorus containing polyester resin, etc. may be used with the said modified PAI resin. The base layer material may contain an organic solvent such as DMF, DMAC, toluene, acetone, and NMP, and a normal filler such as calcium carbonate, if necessary. .

The conductive filler is not particularly limited. For example, conductive powder such as carbon black and graphite, metal powder such as aluminum powder and stainless powder, conductive zinc oxide (c-ZnO), and conductive titanium oxide. (c-TiO _2), conductive iron oxide _{(c-Fe 3 O 4)} , conductive tin oxide (c-SnO ₂₎ conductive metal oxides such as, quaternary ammonium salts, phosphoric acid esters, sulfonic acid Examples thereof include ionic conductive agents such as salts, aliphatic polyhydric alcohols, and aliphatic alcohol sulfate salts. These may be used alone or in combination of two or more.

  The phosphorus-containing polyester resin preferably has a phosphorus content in the range of 3 to 15% by weight of the entire phosphorus-containing polyester resin, and particularly preferably has a phosphorus content in the range of 5 to 10% by weight. It is what is inside. It is preferable for the phosphorus content to be in such a range because flame retardancy is improved.

  The base layer material may be, for example, the modified PAI resin, a conductive filler, an organic solvent, and a filler appropriately blended as necessary, mixed with a stirring blade, and then a ring mill, ball mill, sand mill, etc. It can be prepared by dispersing using.

  Next, the material (surface layer material) used for forming the surface layer 2 is not particularly limited, and examples thereof include silicone resins, fluorine resins, urethane resins, acrylic resins, polyamide resins, and the like. These may be used alone or in combination of two or more. Among these, in consideration of workability, a liquid or solvent-soluble type is preferably used. In addition, for the purpose of preventing dirt, improving the strength of the coating film, or improving the adhesion, a modified resin material may be used, for example, a modified acrylic resin. The modified acrylic resin is not particularly limited as long as it is based on the molecular structure of the acrylic resin and is modified with another resin or resin component, but a silicone-modified acrylic resin is preferably used.

  Examples of the silicone-modified acrylic resin include a silicone graft acrylic resin. The silicone graft acrylic resin is not particularly limited as long as the silicone resin is graft polymerized with the acrylic resin (main chain). Specific examples of this silicone graft acrylic resin include Saimak US-350 manufactured by Toagosei Co., Ltd.

  In addition, as the material for the surface layer, the resin material is subjected to resin crosslinking using a resin crosslinking agent such as isocyanate resin, amino resin, phenol resin, xylene resin, or a photosensitive monomer or polymer. An ultraviolet curable material mixed with a photopolymerization initiator may be used.

  The surface layer material can be prepared, for example, by appropriately blending a modified acrylic resin and an organic solvent such as DMF, toluene, and acetone and mixing with a stirring blade. In order to form each layer with high accuracy, it is preferable to use different types of organic solvents as materials for forming adjacent layers. That is, it is preferable to use different types of organic solvents used for the surface layer material and organic solvents used for the base layer material.

  Here, the endless belt for an electrophotographic apparatus of the present invention shown in FIG. 1 can be produced, for example, as follows.

  That is, in the same manner as described above, a base layer material is prepared, and this is dispenser-coated on the outer peripheral surface of a predetermined mold (cylindrical substrate). Subsequently, this is dried at 150 to 300 ° C. for 3 to 6 hours to form the base layer 1 on the outer peripheral surface of the mold. Next, the surface layer material prepared in the same manner as described above is coated on the outer peripheral surface of the base layer 1 by a dipping method and dried, and then air is blown between the base layer 1 and the cylindrical substrate to form a cylinder. An endless belt having a two-layer structure in which the surface layer 2 is formed on the outer peripheral surface of the base layer 1 can be produced by extracting the shaped substrate.

  On the inner peripheral surface of the base layer 1, it is necessary to set the static friction coefficient to be in the range of 0.2 to 0.5. Preferably, the static friction coefficient is in the range of 0.2 to 0.4. That is, if the static friction coefficient is less than 0.2, slip occurs between the belt and the stretching roller, and the drive performance of the belt is impaired. Conversely, the static friction coefficient is 0.5. If this is exceeded, the occurrence of agglomeration of foreign matter on the inner peripheral surface of the belt becomes remarkable, resulting in adverse effects (such as a belt crack caused by the agglomerate being sandwiched between the belt and the stretching roller). The static friction coefficient can be measured by, for example, HEIDON Tribogear Muse TYPE: 94iII manufactured by Shinto Kagaku Co., Ltd.

  The base layer 1 of the endless belt for an electrophotographic apparatus of the present invention can be produced by an extrusion molding method, an inflation method, a blow molding method, a dipping method, a centrifugal molding method, a spray method, or the like, in addition to the above production method. is there. Further, the formation method of the surface layer 2 is not limited to the above dipping method, and may be the same formation method as the formation method of the base layer 1. And it is good also as an endless belt of the single layer structure which consists only of the base layer 1 by abbreviate | omitting formation of the said surface layer 2. FIG.

  In the present invention, meandering prevention formed by a urethane-based elastomer having a JIS-A hardness of 70 to 90 ° over the entire circumference of both end openings of the belt inner peripheral surface (base layer 1 inner peripheral surface) of the endless belt as described above. It is necessary to provide an operation guide 3 (see FIG. 1). Preferably, the JIS-A hardness of the meandering prevention guide 3 is in the range of 70 to 80 °. That is, when the JIS-A hardness of the meandering prevention guide is less than 70 °, the wear resistance becomes inferior, and adverse effects caused by the generation of the wear debris (the wear debris between the belt and the stretching roller). This is because a belt crack or the like due to the pinching of the belt or the like occurs. On the contrary, when the JIS-A hardness of the meandering prevention guide exceeds 90 °, the flexibility of the meandering prevention guide deteriorates, and the guide end portion (particularly, the edge portion of the adhesive portion with the belt inner peripheral surface). This is because the stress is concentrated on the belt, and as a result, a belt crack is generated.

  The urethane elastomer that is a material for forming the meander-preventing guide 3 is not particularly limited as long as the JIS-A hardness of the meander-preventing guide 3 falls within the above specific range. Urethane, ester urethane, carbonate urethane and the like are used. These may be used alone or in combination of two or more.

  In addition, a conventionally known adhesive or the like is usually used for adhesion between the meandering prevention guide 3 and the entire circumference of both end openings of the belt inner circumferential surface (base layer 1 inner circumferential surface). , Epoxy resin, urethane resin, and modified silicone resin are bonded with a reactive curable adhesive, and no elution occurs after the bonding, and various problems caused by the aggregates (belts Belt cracks and the like due to the agglomerates being sandwiched between the tension roller and the tension roller, which is preferable.

  The thickness of each layer in the endless belt for electrophotographic equipment of the present invention is appropriately set according to the use of the belt, but the thickness of the base layer 1 is usually in the range of 30 to 300 μm, preferably 50 to 200 μm. Is within the range. The thickness of the surface layer 2 is preferably in the range of 0.1 to 10 μm, particularly preferably in the range of 0.5 to 5 μm. Further, the base layer 1 preferably has an inner peripheral length of 90 to 1500 mm and a belt width of about 100 to 500 mm. The thickness of the meandering prevention guide 3 provided on the inner peripheral surface of the base layer 1 is preferably in the range of 0.5 to 2.0 mm, particularly preferably in the range of 0.5 to 1.5 mm. The width is preferably in the range of 3 to 10 mm, particularly preferably in the range of 4 to 7 mm. That is, if the size is set within the above range, the size is suitable for use in an electrophotographic copying machine or the like.

  As described above, the endless belt for an electrophotographic apparatus of the present invention is not limited to the two-layer structure in which the surface layer 2 is directly formed on the outer peripheral surface of the base layer 1, for example, a single layer composed of only the base layer 1. It may be a structure. Further, a three-layer structure in which a thermoplastic resin layer or a rubber elastic layer is interposed between the base layer 1 and the surface layer 2, and both a thermoplastic resin layer and a rubber elastic layer are interposed between the base layer 1 and the surface layer 2. A four-layer structure or the like may be used. However, in these cases, the base layer 1 needs to be formed using the above-mentioned modified PAI resin.

  In this case, the material for the thermoplastic resin layer interposed between the base layer 1 and the surface layer 2 is not particularly limited, but may be a solvent such as methyl ethyl ketone (MEK), toluene, etc., if necessary, together with the thermoplastic resin. Is used. In addition, the conductive filler as described above may be blended in the thermoplastic resin layer material.

  The thermoplastic resin is not particularly limited, and examples thereof include polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene-tetrafluoroethylene copolymer (ETFE). Fluorine resin, polyethylene resin, polystyrene resin, acrylic resin, polycarbonate (PC) resin, polyamide resin, EVA (ethylene-vinyl acetate copolymer) resin, EEA (ethylene-ethyl acrylate copolymer) Coalesced) resin and the like. These may be used alone or in combination of two or more. Among these, it is preferable to use a fluorine-based resin such as PVDF from the viewpoint of excellent flame retardancy.

  The rubber elastic layer material interposed between the base layer 1 and the surface layer 2 may be a vulcanization accelerator, a solvent, a processing aid, an anti-aging agent, etc. Is used. Note that the conductive elastic filler as described above may be blended in the rubber elastic layer material.

  The rubber material is not particularly limited, and chlorinated polyethylene rubber (CPE), chloroprene rubber (CR) and the like are used from the viewpoint of flame retardancy. Among these, the optimum material is selected according to the electrical characteristics, elasticity, and durability required for the endless belt for electrophotographic equipment.

  The endless belt for electrophotographic equipment of the present invention is suitable for use in electrophotographic equipment employing electrophotographic technology such as full-color LBP and full-color PPC, such as toner image transfer, paper transfer conveyance, and photoreceptor substrate. However, the present invention is not limited to this. For example, it can be used for a transfer belt of a monochrome electrophotographic copying machine which is not full color.

  Next, examples will be described together with comparative examples.

[Example 1]
(Preparation of base layer material)
In a reaction vessel equipped with a stirrer, a nitrogen introduction tube, a thermometer, and a cooling tube, 22 parts by weight of MDI (manufactured by Nippon Polyurethane, Millionate MT, Mn: 250.26) (hereinafter abbreviated as “part”) and TODI ( Nippon Soda Co., Ltd., TODI / R203, Mn: 264.29) 29 parts, aromatic polycarboxylic acid anhydride (B1) 37 parts of trimellitic anhydride (Mn: 192.12), specific As silicone polymer (C), 15 parts of carboxylic acid-terminated silicone polymer having one carboxyl group at both ends (manufactured by Toray Dow Corning Silicone, BY16-750, acid value: 75 mgKOH / g, Mn: 1496) And 280 parts of NMP solvent, heated to 130 ° C. over 1 hour with stirring under a nitrogen stream, and allowed to react at 130 ° C. for about 5 hours. Stop response, PAI-NMP solution (solid concentration: 29 wt%) was prepared. Next, 4 parts of carbon black (Show Black Ca220, Show Black N220) was added to the PAI-NMP solution, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Preparation of surface layer material)
100 parts of a silicone graft acrylic resin (Saimak US-350, manufactured by Toagosei Co., Ltd.) and 500 parts of a toluene solvent were blended and mixed with a stirring blade to prepare a surface layer material.

(Production of endless belt)
A cylindrical mold was prepared, and the base layer material was dispenser-coated on the outer peripheral surface to form a base layer on the outer peripheral surface of the mold, followed by heat treatment at 250 ° C. for 2 hours. Next, the surface layer material is coated on the outer peripheral surface of the base layer by dipping, dried, and then blown with air between the base layer and the cylindrical base to extract the cylindrical mold, and the base layer ( An endless belt having a two-layer structure in which a surface layer (thickness: 1 μm) was formed on an outer peripheral surface having a thickness of 80 μm, an inner peripheral length: 780 mm, and a belt width: 250 mm was produced. Subsequently, a belt-shaped meandering prevention guide (thickness: 1 mm, width: 4 mm) made of urethane elastomer (Nippon Valqua, Tafrene R5580) having a JIS-A hardness of 80 ° is used as an epoxy resin-based reaction-curing type. Using an adhesive (EP170, manufactured by Cemedine Co., Ltd.), the entire surface of both end openings on the back surface of the endless belt (base layer inner peripheral surface) was bonded (see FIG. 1). In this way, an intended endless belt for electrophotographic equipment was produced.

[Example 2]
The amount of the specific silicone polymer (C) used for the base layer material of Example 1 was changed to 3 parts and used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same), and the same meandering prevention guide as in Example 1 was used in the same manner. The desired endless belt for electrophotographic equipment was obtained.

Example 3
Instead of the specific silicone polymer (C) used for the base layer material of Example 1, 9 parts of X-22-176DX (acid value: 30 mgKOH / g, Mn: 3740) manufactured by Shin-Etsu Chemical Co., Ltd. were used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, instead of the meandering prevention guide of Example 1, a belt-like meandering prevention guide (thickness: 1 mm, width) made of a urethane elastomer (Tigers Polymer, TR100-70) having a JIS-A hardness of 70 ° : 4 mm), and this was adhered using the same adhesive as in Example 1 to obtain the desired endless belt for electrophotographic equipment.

Example 4
Instead of the specific silicone polymer (C) used for the base layer material of Example 1, 9 parts of X-22-176DX (acid value: 30 mgKOH / g, Mn: 3740) manufactured by Shin-Etsu Chemical Co., Ltd. were used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, instead of the meandering prevention guide of Example 1, a belt-like meandering prevention guide (thickness: 1 mm, width) made of urethane elastomer (Tigers Polymer, TR100-90) having a JIS-A hardness of 90 ° : 4 mm), and this was adhered using the same adhesive as in Example 1 to obtain the desired endless belt for electrophotographic equipment.

Example 5
Instead of the specific silicone polymer (C) used for the base layer material of Example 1, 10 parts of SF8427 (acid value: 47 mgKOH / g, Mn: 2400) manufactured by Toray Dow Corning Silicone Co., Ltd. was used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, the meandering prevention guide similar to that in Example 1 was bonded using a urethane resin-based reaction-curing adhesive (Takelac W-2501, manufactured by Mitsui Takeda Chemical Co., Ltd.), and the endless for the intended electrophotographic apparatus was used. I got a belt.

Example 6
Instead of the specific silicone polymer (C) used for the base layer material of Example 1, 10 parts of SF8427 (acid value: 47 mgKOH / g, Mn: 2400) manufactured by Toray Dow Corning Silicone Co., Ltd. was used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, the meandering prevention guide similar to that in Example 1 was adhered using a modified silicone resin-based reactive curable adhesive (S292, manufactured by Chemtech) to obtain a target endless belt for electrophotographic equipment. .

[Comparative Example 1]
The amount of the specific silicone polymer (C) used for the base layer material of Example 1 was changed to 22 parts and used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same), and the same meandering prevention guide as in Example 1 was used in the same manner. The desired endless belt for electrophotographic equipment was obtained.

[Comparative Example 2]
In place of the specific silicone polymer (C) used for the base layer material of Example 1, X-22-176DX (acid value: 30 mgKOH / g, Mn: 3740) manufactured by Shin-Etsu Chemical Co., Ltd. is used for 0.1 part. It was. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same), and the same meandering prevention guide as in Example 1 was used in the same manner. The desired endless belt for electrophotographic equipment was obtained.

[Comparative Example 3]
The amount of the specific silicone polymer (C) used in the base layer material of Example 1 was changed to 8 parts and used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, instead of the meandering prevention guide of Example 1, a belt-like meandering prevention guide (thickness: 1 mm, width: 4 mm) made of urethane-based elastomer having a JIS-A hardness of 65 ° (manufactured by Seadam Co., DUS614) This was adhered using the same adhesive as in Example 1 to obtain the intended endless belt for electrophotographic equipment.

[Comparative Example 4]
Instead of the specific silicone polymer (C) used for the base layer material of Example 1, 10 parts of SF8427 (acid value: 47 mgKOH / g, Mn: 2400) manufactured by Toray Dow Corning Silicone Co., Ltd. was used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, instead of the meandering prevention guide of Example 1, a belt-like meandering prevention guide (thickness: 1 mm, width: made of urethane elastomer (Nippon VALQUA, Tafrene R5795) having a JIS-A hardness of 95 °. 4 mm), and this was adhered using the same adhesive as in Example 1 to obtain the desired endless belt for electrophotographic equipment.

[Comparative Example 5]
The amount of the specific silicone polymer (C) used in the base layer material of Example 1 was changed to 8 parts and used. Other than that was carried out similarly to Example 1, and prepared the material for base layers. Then, using this base layer material, an endless belt having a two-layer structure was produced in the same manner as in Example 1 (all the surface layer materials and the like were also the same). Subsequently, instead of the meander-preventing guide of Example 1, a strip-shaped ethylene-propylene-diene terpolymer (EPDM) having a JIS-A hardness of 70 ° (manufactured by Nitto Kako, EPT-710Z) is used. A meandering-preventing guide (thickness: 1 mm, width: 4 mm) was used and adhered using the same adhesive as in Example 1 to obtain the intended endless belt for electrophotographic equipment.

  Using the endless belts of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 and 2 below.

[Backside friction coefficient]
The static friction coefficient of the belt back surface (base layer inner peripheral surface) was measured by HEIDON Tribogear Muse TYPE: 94iII manufactured by Shinto Kagaku.

[Bench durability test]
Two metal rollers having a diameter of 13 mm were prepared, and one metal roller was fixed on the table in a state where a seamless belt (width 150 mm) was stretched between the two metal rollers. Next, the other metal roller not fixed to the table is placed so as to be at the end of the table (on the table), and 2 kg of weight is suspended from both ends of the metal roller (total load of 4 kg. Was suspended from the end of the table), the seamless belt was in tension, and the seamless belt was rotated in a laboratory environment (25 ° C. × 40%). Then, the cumulative number of revolutions until cracks could be confirmed in the seamless belt was measured. In the table, "300K <" was displayed for those that could endure 300,000 revolutions or more. The presence / absence of this display is taken as one of the criteria of the present invention.

[Foreign matter adhesiveness]
An endless belt was incorporated into a full-color PPC as a transfer belt, and 30,000 copies were made. Thereafter, wear debris (foreign matter) adhering to the back of the belt was collected, and the presence or absence of tackiness was evaluated by tactile sensation.

[Wear debris convex image defect]
The image after copying 30,000 sheets was visually evaluated according to the following criteria. That is, an image defect (spot density unevenness, etc.) due to convex deformation on the belt surface side, caused by agglomeration of wear debris between the belt back surface and the roller that stretches the belt, has been confirmed. Is displayed as x, and those in which such image defects are not confirmed are displayed as ◯.

[Image shift]
As a result of visual evaluation of the image during copying 30,000 sheets, the image where the image shift due to the belt slip is confirmed is displayed as “Yes”, and the image where such a defect is not confirmed is displayed as “No”. did.

  From the above results, since the back friction coefficient is set within a specific range and the meandering prevention guide is made of a urethane-based elastomer having a specific hardness, any of the products of the examples is worn on the back surface of the belt. There was almost no adhesion of debris or the like, and even if there was adhesion of wear debris, the particle size thereof was fine, there was no image defect caused by sandwiching of wear debris, and cracking of the belt was difficult to occur.

  On the other hand, the product of Comparative Example 1 was excellent in durability and the like, but image displacement due to slip occurred. In Comparative Examples 2 to 5 products, cracks were observed in the durability test, and in particular, other than Comparative Example 4 products, image defects occurred due to sandwiching of wear debris. Moreover, in the comparative example 5 product, the sticky wear debris considered to be due to the wear of the EPDM guide was confirmed by durable use.

  The endless belt for an electrophotographic apparatus of the present invention is suitable for an intermediate transfer belt, a paper transfer conveyance belt, etc. in an electrophotographic apparatus employing an electrophotographic technique such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). Used for.

It is a perspective view which shows an example of the endless belt for electrophotographic apparatuses of this invention. It is a fragmentary sectional view of the endless belt for electrophotographic equipment.

Explanation of symbols

1 base layer 2 surface layer 3 guide for preventing meandering

Claims (3)

An endless belt for an electrophotographic apparatus having at least a base layer, wherein the base layer is formed using a modified polyamideimide resin obtained by copolymerizing the following (A) to (C), and the static friction of the inner peripheral surface of the base layer The coefficient is set in the range of 0.2 to 0.5, and the urethane base elastomer having a JIS-A hardness of 70 to 90 ° is provided over the entire circumference of the opening edge at the left and right ends of the belt on the inner peripheral surface of the base layer. An endless belt for an electrophotographic apparatus, characterized in that a meandering prevention guide is provided.
(A) An aromatic isocyanate compound.
(B) An aromatic polycarboxylic acid anhydride.
(C) A silicone polymer having a polydimethylsiloxane structure in the molecule and having a reactive group for the isocyanate group of (A) at one or both ends.   2. The endless electrophotographic apparatus according to claim 1, wherein the adhesion between the base layer and the meander-preventing guide is made with a reaction-curable adhesive belonging to any of an epoxy resin system, a urethane resin system, and a modified silicone resin system. belt.   The blending ratio of the silicone polymer (C) is set within the range of 1 to 20% by weight of the total amount of the (A) to (C), and is endless for an electrophotographic apparatus according to claim 1 or 2. belt.

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