JP4832935B2 - Endless belt for electrophotographic equipment - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt for an electrophotographic apparatus, and more particularly, to an electrophotographic apparatus employing an electrophotographic technique such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). The present invention relates to an endless belt for electrophotographic equipment used for a transfer conveyance belt or the like.

  In general, endless belts (seamless belts) are widely used for electrophotographic equipment employing electrophotographic technology such as full color LBP and full color PPC for applications such as toner image transfer, paper transfer conveyance, and photoreceptor substrate. Yes. 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.

Then, the endless belt which formed the base layer (base layer) using the polyamide-imide resin or the polyimide resin is proposed by the point which is excellent in rigidity (for example, refer patent document 1, 2).
JP 2001-152013 A JP 2001-354854 A

  However, an endless belt in which a base layer (base layer) is formed using the above polyamideimide resin or polyimide resin has excellent rigidity, but has poor toughness and poor durability (particularly bending durability).

  Conventionally, the revolver layout has been widely used because the position can be detected and corrected for each rotation of the belt, and the toner of each color can be easily superimposed. However, this revolver layout has a slow print speed because it prints out one sheet per four belt rotations. Recently, a tandem layout that can print out one sheet per one belt rotation is fast and can be used for high-speed printing. It is becoming mainstream. As shown in FIG. 2, the tandem layout includes toner cartridges 4a to 4d for each color, and corresponding photoreceptors 5a to 5d, charging members 6a to 6d, primary transfer rolls 7a to 7d, and photoreceptor cleaners 8a to 8d. Are arranged horizontally at substantially equal intervals. The toner images formed on the respective photoreceptors 5a to 5d are transferred onto the endless belt 3 to form one multiple image, which is a primary transfer roll 7a to 7d, a roll 10, a secondary transfer roll 11, and a secondary transfer roll. It is transferred to the copy paper 14 via the facing roll 12. This tandem layout tends to reduce the thickness of the belt unit 9 for compactness. Therefore, the rolls 10 and the like used in the belt unit 9 tend to be reduced in diameter, and the endless belt 3 and each roll (particularly, , The contact portion with the roll 10) also has a sharpened layout. In such a tandem layout, the endless belt 3 (particularly, the sharpened portion) is likely to be broken, so that higher durability (particularly bending durability) is required. When the endless belt 3 having insufficient durability is used, the endless belt 3 (particularly, the base layer portion) is cracked, and the endless belt 3 may be broken in some cases. Further, the endless belt 3 used for the tandem layout tends to have a long circumferential length because the toner cartridges 4a to 4d are laterally arranged. Further, since position detection and correction are not performed during the superposition of the four toner colors, the tension between the endless bell 3 and the roller (especially the roll 10) when the endless belt 3 is driven has a high tension, In particular, it is necessary to suppress the extension of the endless belt 3 in the initial stage of driving as much as possible, and the endless belt 3 is required to have a certain level of rigidity.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an endless belt for electrophotographic equipment that can achieve both high rigidity and high durability.

In order to achieve the above object, the endless belt for electrophotographic equipment of the present invention is a single layer consisting of only a base layer or a multi-layered endless belt consisting of two or more layers including a base layer, At least the base layer is configured to be formed using a polyamideimide resin having the following (A) to (C) as essential components.
(A) Aromatic diamine or aromatic diisocyanate.
(B) Aliphatic diamine or aliphatic diisocyanate.
(C) An aromatic polycarboxylic acid anhydride.

  In order to obtain an endless belt for an electrophotographic apparatus capable of achieving both high rigidity and high durability, the present inventors have conducted extensive research focusing on a base layer (base layer). Then, recalling that an aromatic material (aromatic diamine or aromatic diisocyanate) and an aliphatic material (aliphatic diamine or aliphatic diisocyanate) are used in combination, together with the aromatic material and aliphatic material described above The present inventors have found that the intended purpose can be achieved by forming at least the base layer of an endless belt for electrophotographic equipment using a polyamide-imide resin containing an aromatic polycarboxylic acid anhydride as an essential component. did. That is, it is considered that when an aromatic material is used, the rigidity is excellent, and when an aliphatic material is used, the durability is excellent, so that both high rigidity and high durability can be achieved.

  As described above, the endless belt for an electrophotographic apparatus of the present invention uses a polyamide-imide resin having an aromatic material, an aliphatic material, and an aromatic polyvalent carboxylic acid anhydride as essential components, and is electrophotographic. Since at least the base layer of the endless belt for equipment is formed, it is possible to achieve both high rigidity and high durability, and there is an effect that “color misregistration” does not occur.

  In addition, when the aromatic material (A) is highly filled, the rigidity is excellent, but the toughness is poor, and the durability (particularly bending durability) tends to be inferior. Conversely, the aliphatic material (B) is highly filled. Then, since the belt has insufficient rigidity, the belt tends to stretch when the belt is driven, and a “color shift” defect tends to occur. However, the mole of the aromatic material (A) and the aliphatic material (B) When a polyamideimide resin having a mixing ratio of (A) / (B) = 99/1 to 30/70 is used, both high rigidity and high durability can be achieved at a high level.

  In addition, when a conductive filler is used together with the polyamideimide resin in the base layer of the endless belt, the molecule of the polyamideimide resin is larger than when a polyamideimide resin obtained from a conventional polycondensation of only an aromatic material is used. Since the skeleton is flexible, the conductive filler can easily move when the coating is baked, and it is easy to assemble an appropriate structure, a small amount of conductive filler is required to achieve the same resistance level. The effect of further improving the durability can be obtained.

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

  For example, as shown in FIG. 1, the endless belt for an electrophotographic apparatus of the present invention is configured by directly forming a surface layer 2 on the outer peripheral surface of a base layer 1.

In the present invention, at least the base layer 1 of the endless belt is formed using a polyamideimide resin having the following components (A) to (C) as essential components, which is the greatest feature.
(A) Aromatic diamine or aromatic diisocyanate.
(B) Aliphatic diamine or aliphatic diisocyanate.
(C) An aromatic polycarboxylic acid anhydride.

  The aromatic diamine or aromatic diisocyanate (hereinafter referred to as “aromatic material” as appropriate) (component A) is not particularly limited, and an aromatic diamine and its diisocyanate are used.

  Examples of the aromatic diamine include m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether (ODA), 4,4′-diaminodiphenylsulfone, benzidine, o -Tolidine, 2,4-tolylenediamine, 2,6-tolylenediamine, xylylenediamine and the like. These may be used alone or in combination of two or more.

  Examples of the aromatic diisocyanate include 4,4′-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), tolidine diisocyanate (TODI), xylylene diisocyanate (XDI), lysine diisocyanate (LDI), and naphthalene diisocyanate (NDI). ), Paraphenylene diisocyanate (PPDI), tetramethylxylene diisocyanate (TMXDI) and the like. These may be used alone or in combination of two or more.

  The aliphatic diamine or aliphatic diisocyanate (hereinafter referred to as “aliphatic material” as appropriate) (component B) is not particularly limited, and aliphatic diamines and diisocyanates thereof are used.

  Examples of the aliphatic diamine include ethylene diamine, propylene diamine, hexamethylene diamine, isophorone diamine, and metaxylene diamine. These may be used alone or in combination of two or more.

  Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, and norbornene diisocyanate. These may be used alone or in combination of two or more.

  Next, the anhydride of the aromatic polyvalent carboxylic acid (component C) has an aromatic ring in the molecular structure, and the aromatic material (component A) or aliphatic material (component B). The aromatic polyhydric carboxylic acid monoanhydride, aromatic polyhydric carboxylic acid dianhydride, and the like can be used. 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 above aromatic polyvalent carboxylic acid anhydride (component C).

  Examples of the aromatic polyvalent carboxylic acid monoanhydride 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 polyvalent carboxylic dianhydride 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-tetracarboxylic dianhydride Anhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, decahydronaphthalene-1,4,5,8-tetra Carboxylic dianhydride, 4,8- Methyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic Acid dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic acid Dianhydride, phenanthrene-1,3,9,10-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis (2,3-dicarboxyphenyl) methane Anhydride, 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 dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylene glycol bis (anhydro trimellitate), propylene glycol bis (anhydro trimellitate) and the like. These may be used alone or in combination of two or more.

  Examples of the PAI resin include a mixture of an aromatic diamine or aromatic diisocyanate (component A) and an aliphatic diamine or aliphatic diisocyanate (component B), and an aromatic polycarboxylic acid anhydride (C Component) in a polar solvent such as N, N′-dimethylacetamide or N-methyl-2-pyrrolidone (NMP) while being heated to a predetermined temperature (usually about 60 to 200 ° C.). be able to.

  Here, in the present invention, the molar mixing ratio of the aromatic diisocyanate and the like (component A) and the aliphatic diisocyanate and the like (component B) is A component / B component = 99/1 to 30/70. Is preferable, and A component / B component = 90/10 to 30/70 is particularly preferable. That is, when the molar ratio of the component A exceeds 99 (the molar ratio of the component B is less than 1), the rigidity is excellent but the toughness is poor, and the durability (particularly the bending durability) tends to be inferior, Conversely, if the molar ratio of the A component is less than 30 (the molar ratio of the B component exceeds 70), the rigidity of the belt is insufficient, so that the belt is stretched when the belt is driven, and there is a tendency for a “color shift” defect to occur. Because it is.

  The number average molecular weight (Mn) of the PAI resin is preferably from 5,000 to 100,000, particularly preferably from 10,000 to 50,000. The number average molecular weight (Mn) can be measured by a gel permeation chromatograph (GPC) method.

  In the present invention, as a material for forming the base layer 1 (base layer material), a conductive filler, a release agent, an antifoaming agent, a leveling agent, a heat stabilizer, a flame retardant, etc. may be used together with the PAI resin. There is no problem. 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 metal oxides such as conductive tin oxide (c-SnO ₂ ), quaternary ammonium salts, phosphate esters, sulfonic acids 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 blending amount of the conductive filler is preferably 5 to 50 parts with respect to 100 parts by weight (hereinafter abbreviated as “part”) of the total amount of the component (A), the component (B) and the component (C), Particularly preferred is 5 to 20 parts. That is, if the blending amount of the conductive filler is less than 5 parts, uniformity and controllability of resistance tend to be deteriorated, and conversely if it exceeds 50 parts, durability tends to be deteriorated. It is.

  Moreover, as said phosphorus containing polyester-type resin, what has a phosphorus content in the range of 3-15 weight% of the whole phosphorus containing polyester-type resin is preferable, Most preferably, phosphorus content is 5-10 weight%. . It is preferable for the phosphorus content to be in such a range because flame retardancy is improved.

  The base layer material can be produced, for example, as follows. That is, the base layer material can be prepared by preparing a PAI resin solution by the same method as described above, adding carbon black or the like to the PAI resin solution, mixing with a stirring blade, and then dispersing by ball milling.

  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, a base layer material is prepared in the same manner as described above, and this is spray-coated on the surface of a mold (cylindrical substrate). Next, this is dried at 150 to 300 ° C. for 3 to 6 hours to form the base layer 1 on the surface of the mold. Next, the surface layer material prepared in the same manner as described above is coated on the 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 cylindrical shape. An endless belt (see FIG. 1) having a two-layer structure in which the substrate is extracted and the surface layer 2 is formed on the surface of the base layer 1 can be produced. In addition, the formation method of the surface layer 2 is not limited to the said dipping method, You may form by spray coating similarly to the formation method of the base layer 1.

  In addition, the base layer 1 of the endless belt for electrophotographic equipment 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, or the like, in addition to the above production method.

  The thickness of each layer of 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 30 to 300 μm, preferably 50 to 200 μm. Moreover, 0.1-10 micrometers is preferable and, as for the thickness of the surface layer 2, Most preferably, it is 0.5-5 micrometers. The endless belt for electrophotographic equipment of the present invention preferably has an inner peripheral length of 90 to 1500 mm and a width of about 100 to 500 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.

  The endless belt for electrophotographic equipment 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 as shown in FIG. The endless belt for electrophotographic equipment of the present invention has, for example, a single-layer structure composed of only the base layer 1, 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 the base layer 1 A four-layer structure in which both a thermoplastic resin layer and a rubber elastic layer are interposed between the surface layer 2 and the surface layer 2 may be used. However, in these cases, the base layer 1 needs to be formed using a special PAI resin having the aforementioned components A to C as essential components.

  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. However, the present invention is not limited to these examples.

[Anhydrous aromatic polycarboxylic acid (component C)]
Trimellitic anhydride (TMA) (Mn: 192.12)

[Aromatic diisocyanate (MDI) (component A)]
Millionate MT (Mn: 250.06), manufactured by Nippon Polyurethane Industry

[Aromatic diisocyanate (TODI) (component A)]
Nippon Soda Co., Ltd., TODI / R203 (Mn: 264.29)

[Aliphatic diisocyanate (HDI) (component B)]
Takenate 700 (Mn: 169) manufactured by Mitsui Takeda Chemical Co., Ltd.

[Aromatic diamine (component A)]
4,4'-diaminodiphenyl ether (ODA) [Wakayama Seika Kogyo Co., Ltd., DPE (ODA), Mn: 200.2]

[Aliphatic diamine (IPDA) (component B)]
VESTAMINIPD (Mn: 170) manufactured by Degussa

[Anhydrous aromatic polycarboxylic acid (component C)]
Pyromellitic dianhydride (PMDA) (manufactured by Daicel Chemical Industries, Mn: 218)

〔Carbon black〕
Cabot Japan, Show Black N220

  Next, an endless belt was produced using the above materials as follows.

[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, trimellitic anhydride, aromatic diisocyanate, aliphatic diisocyanate, and NMP solvent were each in the proportions shown in Table 1 below. The temperature was raised to 130 ° C. over 1 hour with stirring in a nitrogen stream, and the reaction was stopped at 130 ° C. for about 5 hours. The reaction was stopped, and a PAI-NMP solution (solid content concentration: 30% by weight) was added. Prepared. Next, carbon black was blended into the PAI-NMP solution in the proportions shown in Table 1 below, mixed with a stirring blade, and then dispersed in a ball mill to prepare a base layer material.

(Production of endless belt)
A mold (cylindrical substrate) was prepared, the surface layer material was spray-coated on this surface, and the temperature was raised from room temperature to 250 ° C. over 2 hours, followed by heat treatment at 250 ° C. for 1 hour. Next, by blowing air between the base layer and the cylindrical base body, the cylindrical base body was extracted, and an endless belt having a single layer structure consisting of only the base layer (thickness: 80 μm) was produced.

[Examples 2-6, 8, 9, Comparative Examples 1-4]
(Preparation of base layer material)
As shown in Table 1 and Table 2 above, a base layer material was prepared in the same manner as in Example 1 except that the type and amount of each component were changed.

(Production of endless belt)
An endless belt having a single-layer structure consisting only of a base layer (thickness: 80 μm) was produced in the same manner as in Example 1 except that the base layer material was used.

Example 7
(Preparation of base layer material)
A base layer material was prepared in the same manner as in Example 2 shown in Table 1.

(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 mold (cylindrical substrate) was prepared, the surface layer material was spray-coated on this surface, and the temperature was raised from room temperature to 250 ° C. over 2 hours, followed by heat treatment at 250 ° C. for 1 hour. Next, the surface layer material is coated on the surface of the base layer by a dipping method and dried, and then the air is blown between the base layer and the cylindrical base body, whereby the cylindrical base body is extracted and the base layer (thickness: An endless belt having a two-layer structure in which a surface layer (thickness: 1 μm) was formed on the surface of 80 μm was produced.

  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 above.

[Tensile modulus]
The tensile elastic modulus was measured according to JIS K7127. The tensile speed was 10 ± 2.0 mm per minute.

[Actual machine evaluation (color shift)]
Each endless belt was incorporated in the tandem layout shown in FIG. 2, and actual machine evaluation (color shift) was performed. In the evaluation, “◯” indicates that there was no color misregistration, “Δ” indicates that the color misregistration was confirmed with a 50 × microscope, and “x” indicates that the color misregistration was confirmed visually.

[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 an endless belt (width 150 mm) was stretched between the two metal rollers. Next, the other metal roller that is not fixed to the table is placed at the end of the table, and 2 kg of weight is suspended from both ends of this metal roller (total load 4 kg), and the laboratory environment (25 ° C x 40% RH), the endless belt was driven to rotate. Then, the cumulative number of revolutions until a crack was confirmed on the endless belt was measured.

  From the results shown in Tables 1 and 2, all of the examples had high elastic modulus, excellent durability, and no color shift.

  On the other hand, the product of Comparative Example 1 was rigid and easily cracked because the main polymer was not a PAI resin but a polyimide resin, and was inferior in durability. Comparative Examples 2 and 4 use only aromatic diisocyanate and the like (component A) and do not use aliphatic diisocyanate and the like (component B) together, so the amount of carbon black is large and the durability is inferior. On the other hand, the example product uses aromatic diisocyanate and the like (component A) in combination with aliphatic diisocyanate and the like (component B), so that flexibility is imparted to the physical properties of the polymer, and a comparative example Compared with 2,4 products, the amount of carbon black is reduced. For this reason, there are few interfaces between the polymer and the carbon black that are most likely to cause micro cracks that cause the belt to break, and the micro cracks generated therefrom are difficult to connect with each other, so that the durability is excellent. Since the product of Comparative Example 3 did not use any aromatic diisocyanate, the rigidity of the belt was insufficient, and the belt was stretched when the belt was driven, resulting in a “color shift” problem.

  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 technology such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). Used for.

It is a fragmentary sectional view which shows an example of the endless belt for electrophotographic apparatuses of this invention. It is a schematic diagram which shows a tandem layout.

Explanation of symbols

1 base layer 2 surface layer

Claims (4)

An endless belt for an electrophotographic apparatus consisting of a single layer consisting of only a base layer, or a multilayer including two or more layers including a base layer, at least the base layer of which the following (A) to (C) are essential components An endless belt for an electrophotographic apparatus, characterized by being formed using a polyamideimide resin.
(A) Aromatic diamine or aromatic diisocyanate.
(B) Aliphatic diamine or aliphatic diisocyanate.
(C) An aromatic polycarboxylic acid anhydride.   The endless belt for an electrophotographic apparatus according to claim 1, wherein the molar mixing ratio of (A) to (B) is (A) / (B) = 99/1 to 30/70.   The endless belt for an electrophotographic apparatus according to claim 1 or 2, wherein at least the base layer is formed by using a conductive filler together with the polyamideimide resin.   4. The electrophotographic apparatus according to claim 3, wherein the blending amount of the conductive filler is 5 to 50 parts by weight with respect to 100 parts by weight of the total amount of the component (A), the component (B) and the component (C). For endless belt.

Images