JP5383140B2 - Method for producing multilayer elastic belt for electrophotographic apparatus - Google Patents

Description

  The present invention relates to a method for producing a multilayer elastic belt used in an image forming apparatus using an electrophotographic system such as a copying machine, a printer, and a facsimile, and a method for evaluating the belt. Specifically, a method for producing an electrophotographic belt such as an intermediate transfer belt or a transfer conveyance belt used for transferring a toner image on an electrostatic latent image formed on a photoreceptor to a recording material such as paper; The present invention relates to a method for evaluating the belt.

  In order to cope with the high image quality of the intermediate transfer belt, as described in Patent Document 1, an intermediate transfer belt having a two-layer or three-layer structure having an elastic material layer has been proposed.

  Further, Patent Document 2 and the like have devised one using urethane rubber for the elastic layer. These belts are usually formed by a method in which an elastic layer and a surface layer are sequentially coated on the surface of a resin belt such as polyimide as a base material layer, a method in which an elastic layer and a base material layer are sequentially molded on the inner surface of a mold, a calendar roll, etc. Manufactured by laminating sheeted sheets.

  An intermediate transfer belt made of such a rubber elastic body or provided with a rubber elastic body layer is excellent in flexibility, so that a transfer area with a photoconductor or the like that contacts the intermediate transfer belt during primary transfer can be easily and stably formed. At the same time, it is considered that the compressive stress applied to the toner between the photosensitive member and the like is reduced, and it is considered useful for countermeasures against image dropout defects and for improving the sharpness of fine line printing.

  Further, Patent Document 3 deals with a problem that an image is lost in a concave portion at the time of secondary transfer in an intermediate transfer belt that does not have elasticity when a recording medium having a large surface irregularity is used. It is said to be effective.

  Further, Patent Document 4 takes up the problem of cracks in the surface layer caused by the difference in stretchability when the intermediate transfer belt having the structure of the hard surface layer and the elastic layer is curved and describes a solution. .

  That is, Patent Document 3 proposes an intermediate transfer belt having an IRHD micro hardness of 60 degrees or less and Patent Document 4 having a dynamic ultra-micro hardness of 0.25 or less.

  However, the IRHD micro hardness tester is not suitable as a method for measuring thin objects with a total thickness of 0.5 mm or less because of the structure in which the needle is inserted deeply. Therefore, it must be said that the method of measuring the hardness of a multi-layer intermediate transfer belt of usually about 0.3 mm is not reliable.

  In order to make the IRHD micro hardness 60 degrees or less, it is indispensable to use a rubber material such as fluoro rubber for the surface layer itself. However, when the surface layer of the intermediate transfer belt is formed of a rubber elastic body formed of fluororubber, the release property of the toner is not always sufficient due to the adhesiveness (tackiness) of fluororubber, and it is formed on the surface of the intermediate transfer belt. This causes a problem that the toner in the lowermost layer of the toner image is not transferred to a medium such as paper and remains on the surface of the intermediate transfer belt. That is, the efficiency of secondary transfer is reduced.

  In addition, when a cleaning blade made of silicone rubber or urethane rubber is used in the cleaning process to remove the toner remaining on the surface of the intermediate transfer belt, the surface of the intermediate transfer belt is sticky, which In the worst case, the blade will be damaged.

  In such a case, in order to obtain releasability from the toner, a large amount of fluororesin was added to the original fluororubber material, or a fluororesin was added based on urethane resin or acrylic resin instead of fluororubber. In this case, the IRHD micro hardness of the intermediate transfer belt is much higher than 60 degrees.

  Next, when measuring the dynamic ultra-fine hardness with a constant applied load, the measurement indenter is pushed in from the surface to some extent, so it is more strongly affected by the hardness of the intermediate layer rubber than the surface layer. There is a tendency. For example, in the example of Patent Document 4, the calculated indentation depth is 2.7 μm or more. However, when the thickness of the surface layer is desired to be 5 μm or less, since the indenter is pushed to half or more of the thickness in this method, the influence of the hardness of the intermediate layer is almost dominant over the hardness of the surface layer. Therefore, even if the surface layer is hard, if the hardness of the rubber constituting the intermediate layer is made soft, the dynamic ultra-small hardness can be reduced numerically.

  On the other hand, in the intermediate transfer belt, the hardness of the surface layer plays an important role in countermeasures against the above-described image dropout defect and improvement in the fineness of fine line printing. That is, in the primary transfer, even if the intermediate layer is made soft, an excessive pressure is easily applied to the toner in the hard surface layer, and a sufficient compressive stress relaxation effect cannot be obtained.

  From the above, what is required for the surface layer of the multilayer intermediate transfer belt is that the surface is not sticky, is a relatively soft material, and has a thin film thickness. In addition, there is a need for a method for measuring the hardness of the multilayer intermediate transfer belt associated with these matters, that is, a method for measuring the difference in hardness of the surface layer even when an intermediate layer made of a soft rubber material is used. .

However, so far, it is possible to more appropriately manage and evaluate the transfer characteristics of the multi-layer intermediate transfer belt, such as the reduction of voids in primary transfer and the improvement of follow-up to uneven paper in secondary transfer. There was no report about the measurement method. For this reason, development of an epoch-making management method related to the hardness of the belt more in line with actual use has been awaited.
Japanese Patent No. 3248455 Japanese Patent Laid-Open No. 2001-282009 JP 2006-178232 JP JP 2006-276302 A

  As described above, with an intermediate transfer belt having a multilayer structure used in an image forming apparatus, primary transfer characteristics with clear image printing and fine line printing, as well as releasability and cleaning, paper unevenness followability, etc. Is required to have good secondary transfer characteristics. However, in the prior art, it was difficult to grasp the evaluation of the primary and secondary transfer characteristics in relation to the physical values of the belt.

  Accordingly, an object of the present invention is to provide a method for measuring physical values of a multi-layer intermediate transfer belt that can evaluate the primary and secondary transfer characteristics with good reproducibility.

  Another object of the present invention is to provide a method for evaluating the primary and secondary transfer characteristics of a multilayer intermediate transfer belt indirectly and with good reproducibility by measuring physical values of the belt.

  It is another object of the present invention to provide a method for producing a multilayer intermediate transfer belt having excellent primary and secondary transfer characteristics, which incorporates a step of measuring physical values of the belt.

  As a result of intensive studies to solve the above problems, the present inventor has used a dynamic ultra-micro hardness meter and the thickness of the surface layer is 5 μm or less only when the indentation depth is constant. It was found that the difference in the hardness of the material constituting the surface layer can be quantified even with an extremely thin multilayer belt.

  Optimal secondary transfer characteristics required for intermediate transfer belts, such as primary transfer characteristics with clear image printing and fine line printing, follow-up to irregularities on the surface of the medium, and good releasability and cleanability In order to achieve a proper balance, it has been found that it is important to appropriately control the Martens hardness measured from the surface of the intermediate transfer belt.

  Based on this knowledge, further studies have been made and the present invention has been completed. That is, the present invention provides the following elastic belt.

Item 1 A method for producing a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side Because
(1) A first belt consisting of at least two layers, a surface layer containing a releasable material and an elastic layer containing an elastic rubber material, and a second belt consisting of a base material layer containing a high-strength resin material are manufactured separately. The process of
(2) a step of producing a multilayer elastic belt for an electrophotographic apparatus by bonding the elastic layer side of the first belt and the second belt; and (3) the electrophotographic apparatus using a dynamic ultra-micro hardness meter. Confirming that the value of Martens hardness (HMT115) measured by fixing the indentation depth from the surface layer of the multilayer elastic belt is 5 N / mm ² or less,
The manufacturing method characterized by including.

  Item 2 The method according to Item 1, wherein in (3), the indentation depth is fixed in the range of 0.2 to 2 μm from the surface layer.

  Item 3 The method according to Item 1, wherein the surface layer has a thickness of 4 µm or less.

  Item 4 The method according to Item 1, wherein the surface layer is a layer containing a fluororesin.

  Item 5. The method according to Item 1, wherein the elastic layer is a layer containing a polyurethane elastomer.

  Item 6 The method according to Item 1, wherein the material of the base material layer is at least one selected from the group consisting of polyimide, polyamideimide, polycarbonate, PVDF, polyamide, and an ethylene-tetrafluoroethylene copolymer.

  Item 7 The method according to Item 1, wherein the belt has an endless tubular shape.

Item 8 Primary transfer of a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side A method for evaluating the property and secondary transfer property,
(1) a step of measuring the Martens hardness (HMT115) value by fixing the indentation depth from the surface layer of the multilayer elastic belt for an electrophotographic apparatus using a dynamic ultra-micro hardness meter; and (2) A step of checking whether the Martens hardness value is 5 N / mm ² or less,
Evaluation method including

  Item 9 A surface layer of a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side Method of measuring hardness in thickness direction from the side, using a dynamic ultra-micro hardness meter to fix the indentation depth from the surface layer of the multilayer elastic belt for an electrophotographic apparatus, Martens hardness (HMT115) A measurement method characterized by measuring the value of.

Item 10 A multilayer elastic belt for an electrophotographic apparatus, comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side. The value of Martens hardness (HMT115) measured by fixing the indentation depth in the range of 0.2 to 2 μm from the surface layer of the multilayer elastic belt for an electrophotographic apparatus using a dynamic ultra-small hardness meter is 5N A multilayer elastic belt for an electrophotographic apparatus, characterized in that it is / mm ² or less.

  The method for measuring the hardness of the multilayer intermediate transfer belt of the present invention uses a dynamic ultra-micro hardness meter to fix the indentation depth from the surface layer of the multilayer elastic belt for an electrophotographic apparatus, and to determine the Martens hardness (HMT115). taking measurement. Thereby, the primary and secondary transfer characteristics of the multilayer intermediate transfer belt can be indirectly evaluated. By controlling the measured value of Martens hardness within a predetermined range, a multilayer intermediate transfer belt having excellent primary transfer characteristics and secondary transfer characteristics can be obtained.

As a specific example, by controlling the Martens hardness (HMT115) measured at a depth of 1 μm from the surface layer with a dynamic micro hardness tester to 5 N / mm ² or less, there is no image void and fine line printing. It is possible to produce a multilayer intermediate transfer belt having clear primary transfer characteristics, followability to unevenness on the surface of the medium, and secondary transfer characteristics with good releasability and cleaning properties.

  In the present invention, an intermediate layer made of a soft rubber material is used by measuring the value of Martens hardness (HMT115) while fixing the indentation depth from the surface layer with a dynamic ultra-micro hardness meter. Even in this case, the difference in hardness of the surface layer can be numerically differentiated even after the finished belt is formed. As a result, a highly reliable management method can be obtained in the development and production process of the multilayer intermediate transfer belt.

The present invention relates to a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side. A manufacturing method comprising:
(1) A first belt consisting of at least two layers, a surface layer containing a releasable material and an elastic layer containing an elastic rubber material, and a second belt consisting of a base material layer containing a high-strength resin material are manufactured separately. The process of
(2) a step of producing a multilayer elastic belt for an electrophotographic apparatus by bonding the elastic layer side of the first belt and the second belt; and (3) the electrophotographic apparatus using a dynamic ultra-micro hardness meter. Confirming that the Martens hardness (HMT115) measured by fixing the indentation depth from the surface layer of the multilayer elastic belt for use is 5 N / mm ² or less,
It is related with the manufacturing method characterized by including.

Hereinafter, each step will be described.
Process (1)
In the step (1), a first belt composed of at least two layers of a surface layer containing a releasable material and an elastic layer containing an elastic rubber material is separated from a second belt consisting of a base material layer containing a high-strength resin material. Manufacture with the body.

Formation of surface layer The surface layer in the multilayer elastic belt is a layer for directly placing toner and transferring and releasing the superimposed four color toners onto paper.

  As the material for the surface layer, a releasable material is usually used from the viewpoint of facilitating release of the toner. A fluororesin is suitable as the material. Examples of such fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether (PFA), tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride copolymer (THV), and polyvinylidene fluoride. Ride (PVDF), a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) (VDF-HFP copolymer), or a mixture thereof. The copolymer of VDF and HFP preferably has a HFP ratio of about 1 to 15 mol%. Of these, PVDF and VDF-HFP copolymers are preferred.

  Many fluororesin materials alone are difficult to adhere to the rubber constituting the elastic layer. In this case, urethane resin or acrylic resin may be used as the binder. Specifically, paints in which PTFE is dispersed in these binders are used.

  Also, copolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride (THV), polyvinylidene fluoride (PVDF), copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) (VDF-HFP) When a copolymer) or a mixture thereof is selected, since the inherent surface energy is relatively large, adhesion to rubber is relatively easy by using a primer or the like, and can be used without a binder.

  Further, a fine powder of polytetrafluoroethylene (PTFE) may be added to these materials. In this case, the powder may be directly dispersed in a raw material solution to be described later, or a dispersion previously diluted with a solvent or the like may be used, and the polytetrafluoroethylene fine particle powder relative to the weight of the fluororesin raw material in the raw material solution Can be added in an amount of not more than 20% by weight, preferably not more than 10% by weight.

The volume resistivity of the surface layer is usually 10 ¹³ Ω · cm or more, more preferably 10 ¹³ to 10 ¹⁵ Ω · cm. In addition, it is possible to control the semiconductivity by adding a conductive agent such as carbon black, but since the effect is limited and uniform dispersion is difficult, the surface layer does not contain a conductive agent. May be. Since the surface layer is not affected by the change in the environment (temperature, humidity, etc.), stable primary and secondary transfer of the toner is possible, and high image quality can be realized.

  The thickness of the surface layer is usually 4 μm or less, preferably 0.5 to 3.5 μm, more preferably 1 to 3 μm. If the thickness is too large, the rubber elasticity of the elastic layer is impaired, which is not preferable, and if the thickness is too thin, there is a problem in durability such that a hole is easily formed in the surface layer.

  The static friction coefficient of the surface layer is preferably low in view of secondary transfer properties, but it is preferable to provide a lower limit value from the viewpoint of ensuring cleaning properties and preventing blade noise. From this, the static friction coefficient is preferably 0.1 to 0.8, more preferably 0.15 to 0.35, and particularly preferably 0.2 to 0.3.

  Further, it is preferable that the surface layer has flexibility to improve the transfer efficiency of the primary transfer image, such as prevention of voids, since the effect of enveloping the toner can be expected. Specifically, the Rockwell hardness on the JIS K 7202 compliant R scale is 100 degrees or less, more preferably 80 degrees or less, particularly 40 to 80 degrees. If it is less than 40 degrees, the static friction coefficient increases due to the influence of the elastic layer that is the base, and the secondary transferability may decrease. Specifically, a surface layer made of fluororubber is an example. In order to improve secondary transferability, it is preferable to add a fluororesin to improve the toner releasability.

The aim of the hardness of the material constituting the surface layer and the thickness of the surface layer is not one by the combination, but the final multilayer elastic belt is pushed from above the surface layer by a dynamic micro hardness tester. It is important to prepare such that the value of Martens hardness (HMT115) measured at a constant (for example, 0.2 to 2 μm, particularly 1 μm) is 5 N / mm ² or less. If this value exceeds 5N / mm ^2, either the stiffness-thickness of the surface layer, which means that it inhibits the flexibility of the elastic layer of the base, the effect of such anti-dropout in the fine line It will disappear. Conversely, in order to make maximum use of the softening effect of the elastic layer, this value should be low, preferably 3 N / mm ² or less, more preferably 2.7 N / mm ² or less, especially 0.5 to 2.7 N / mm ² . is there.

  The film formation of the surface layer will be described below by taking as an example the case of centrifugal molding of a fluororesin.

  First, it is preferable to adjust the weight of the material so that the finished surface layer has a target thickness of 1 to 4 μm. The weighed surface layer material is dissolved in a solvent to obtain a liquid raw material, which is cast on the inner surface of a cylindrical mold and centrifuged. Solvents used include water; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester solvents such as ethyl acetate and butyl acetate; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; Alternatively, a mixed solvent thereof or the like is used. The liquid raw material may have a solid content concentration of about 2 to 30% by weight.

  Centrifugal molding of the surface layer can be performed as follows using, for example, a cylindrical mold. After injecting the liquid raw material in an amount equivalent to obtaining the final thickness into the stopped cylindrical mold, the rotational speed is gradually increased to the speed at which the centrifugal force works, and the centrifugal force uniformly flows over the entire inner surface. Extend.

  The cylindrical mold has a mirror inner surface, specifically a surface roughness (JIS B0601-1994 10-point average roughness) of 1 μmRz or less. The inner surface of this mold is the outer surface of the endless multilayer elastic belt. Transcribed. In addition, the inner surface of the mold can be blasted for the purpose of adjusting the belt surface layer to have desired irregularities.

  Further, a release agent is applied to the inner surface of the cylindrical mold so that the film after the raw material is cured can be released from the inner surface of the mold. As the release agent, a fluorine release agent or a silicone release agent is used.

  The cylindrical mold is placed on a rotating roller, and indirectly rotated by the rotation of the roller. The size of the mold can be appropriately selected according to the desired size of the surface layer, that is, the outer diameter of the multilayer elastic belt.

  For the heating, a heat source such as a far-infrared heater is disposed around the mold, and indirect heating from the outside is performed. Usually, the temperature may be gradually raised from room temperature to about 120 to 200 ° C. and heated at the temperature after the temperature raising for about 0.5 to 2 hours. Thereby, the liquid raw material injected into the inner surface of the cylindrical mold is cured, and a seamless (seamless) tubular surface layer can be formed on the inner surface of the cylindrical mold.

Production of first belt (formation of elastic layer)
The elastic layer in the multilayer elastic belt is made of an elastic rubber material, specifically, a cured product of liquid urethane rubber. For example, a liquid urethane rubber and, if necessary, an elastic layer material containing a conductive agent (electronic conductive agent, ionic conductive agent, etc.) in the liquid urethane rubber is applied and cured on the inner surface of the surface layer obtained above. Manufactured.

  Examples of the liquid urethane rubber include polyurethane elastomers, and those having a hardened urethane rubber type A hardness (JIS K6253) of 25 to 70 degrees, more preferably 35 to 55 degrees are preferred. Specific examples include Pandex and Urehyper manufactured by DIC Corporation, Takenate manufactured by Mitsui Chemicals Polyurethane Corporation, and the like.

Usually, some of these urethane rubbers have a volume resistivity of about 10 ⁹ Ω · cm to 10 ¹¹ Ω · cm without adjusting the resistance. In many cases, the environmental variation is large when the temperature and humidity environment is shaken. Accordingly, it is desirable to select a urethane rubber having a volume resistivity of 10 ¹³ Ω · cm or more that is not originally adjusted for resistance. The resistance of this urethane rubber is adjusted with a conductive agent whose electrical characteristics are less dependent on the environment, that is, carbon black or lithium salt.

  Examples of the electronic conductive agent include carbon black such as acetylene black and ketjen black. The compounding amount of the electronic conductive agent (particularly, carbon black) is 5 to 40 parts by weight, preferably 10 to 30 parts by weight, and more preferably 10 to 25 parts by weight with respect to 100 parts by weight of the liquid urethane rubber.

Thus, by adding an electronic conductive agent (particularly, carbon black) to the insulating urethane rubber, the elastic layer has a volume resistivity of about 10 ⁷ to 10 ¹³ Ω · cm (preferably about 10 ⁹ to 10 ¹² Ω · cm. Semi-conductivity) is provided, and accurate semiconductivity suitable for the purpose can be obtained for various resistance value requirements. Further, since the obtained belt is electronically conductive by carbon black, it exhibits stable semiconductivity that is hardly affected by the external environment such as temperature and humidity.

The ion conductive agent is not particularly limited, and examples thereof include lithium salts such as lithium bisimide (CF ₃ SO ₂ ) ₂ NLi and lithium trismethide (CF ₃ SO ₂ ) ₃ CLi. Specific examples include Sanconol manufactured by Sanko Chemical Co., Ltd. This lithium salt is considered not to exhibit conductivity due to moisture absorption which is dependent on the environment, but to exhibit conductivity when lithium ions move due to molecular motion of oxygen. Therefore, the environment dependency is reduced, and the elastic layer constituting rubber of the transfer belt is preferably used. When an ionic conductive agent is added, the addition amount is about 0.1 to 3.0 parts by weight with respect to 100 parts by weight of the liquid urethane rubber.

  The liquid urethane material whose resistance is adjusted by any of the methods in this way is put into the inner surface of the surface layer formed on the inner side of the mold and is centrifugally molded. If the viscosity of the liquid urethane material is too high during centrifugal molding, it may be appropriately diluted with an ester solvent such as ethyl acetate or butyl acetate, or a solvent such as toluene or xylene. As the centrifugal molding method, for example, the same one as the above-mentioned surface layer molding equipment is used. The molding temperature is gradually heated from room temperature, raised to about 110 to 160 ° C., which is lower than the heat resistance limit of urethane rubber, and kept in this state for about 0.5 to 2 hours to complete the curing.

  For the purpose of improving adhesion between the surface layer and the elastic layer, a method of applying a primer on the surface layer side by spraying, a method of adding a silane coupling agent to the liquid urethane material, a method of performing both, etc. You may take it.

The volume resistivity of the elastic layer is usually about 10 ⁷ to 10 ¹³ Ω · cm, preferably about 10 ⁹ to 10 ¹² Ω · cm, from the viewpoint of transferring toner as a belt by electrical control.

  The thickness of the elastic layer is usually 50 to 400 μm, preferably 120 to 300 μm, in consideration of the flexibility of the belt surface and prevention of image displacement during use.

Production of second belt (formation of base material layer)
The base material layer in the multilayer elastic belt is a layer for preventing deformation due to stress applied to the belt during driving. Therefore, mechanical property strength is required.

  Examples of the resin material for the base material layer include high-strength resin materials such as polyimide, polyamideimide, polycarbonate, PVDF, polyamide, and ethylene-tetrafluoroethylene copolymer, and polyimide and polyamideimide are particularly preferable. .

  The polyimide which is a typical example is usually produced by polycondensing a tetracarboxylic dianhydride and a diamine or diisocyanate as monomer components by a known method.

  Examples of polyimide tetracarboxylic dianhydrides include pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6. -Biphenyltetracarboxylic acid, 2,2 ', 3,3'-biphenyltetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 3,3 ', 4,4'-diphenyl ether tetracarboxylic acid 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, azobenzene-3,3 ′, 4,4′-tetracarboxylic acid, bis ( 2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3 4-di-carboxyphenyl) dianhydride such as hexafluoropropane, and the like.

  Examples of the diamine include m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine, p-xylylenediamine, 1,4 -Diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4'-diaminobiphenyl, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,4'-diamino Diphenyl ether, 4,4'-diaminodiphenyl ether (ODA), 4,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminoazobenzene, 4,4 '-Diaminodiphenylmethane, β, β-bis (4-aminophen Nyl) propane and the like.

  As said diisocyanate, the compound etc. which the amino group in the above-mentioned diamine component substituted by the isocyanate group are mentioned.

  Another typical example, polyamideimide, is produced by condensation polymerization of trimellitic acid and diamine or diisocyanate by a known method. In this case, the same diamine or diisocyanate as the above-mentioned polyimide raw material can be used.

  The thickness of the base material layer is usually 30 to 120 μm, preferably 50 to 100 μm, considering the stress and flexibility applied to the belt during driving.

  The base material layer may contain a conductive agent as necessary. As the conductive agent, carbon black mentioned in the elastic layer can be used. When the conductive agent is included, the amount used is usually about 5 to 25 parts by weight with respect to 100 parts by weight of the base layer resin. As a result, the base material layer can have a resistivity suitable for the intermediate transfer belt.

  When polyimide is used as the resin for the base material layer, for example, the base material layer can be formed as follows. The tetracarboxylic dianhydride which is the raw material of the polyimide described above is reacted with diamine or diisocyanate in a solvent to make a polyamic acid solution once. This polyamic acid solution should just be about 10 to 40 weight% by solid content concentration.

  Examples of the solvent include N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”), N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphospho An aprotic organic polar solvent such as amide or 1,3-dimethyl-2-imidazolidinone is used. One or two or more of these solvents may be used. In particular, NMP is preferable.

  In order to impart desired semiconductivity to the base material layer, as described above, about 5 to 25 parts by weight of conductive agent such as carbon black is added to the polyamic acid solution with respect to 100 parts by weight of the base material resin as necessary. You may do it. In this case, the carbon black may be uniformly dispersed with a ball mill. Thereby, the material for base material layers containing a polyamic acid and a electrically conductive agent as needed is obtained.

  The obtained material for the base layer is subjected to centrifugal molding using a cylindrical mold or the like in the same manner as the surface layer / elastic layer. However, the inner surface of the mold in this case may be mirror-finished, but may have irregularities such as blasting as a method for increasing the adhesion area with the elastic layer made of a rubber material. In heating, the inner surface of the mold is gradually heated to reach about 100 to 190 ° C., preferably about 110 to 130 ° C. (first stage heating). The temperature raising rate may be about 1 to 2 ° C./min, for example. The belt is maintained at the above temperature for 20 minutes to 3 hours, and approximately half or more of the solvent is volatilized to form a self-supporting belt.

  Next, as the second stage heating, treatment is performed at a temperature of about 280 to 400 ° C. (preferably about 300 to 380 ° C.) to complete imidization. Also in this case, it is preferable not to reach this temperature from the first stage heating temperature all at once, but to gradually increase the temperature to reach that temperature. The second stage heating may be performed while the endless belt is attached to the inner surface of the cylindrical mold. When the first stage heating is finished, the endless belt is peeled off from the mold, taken out, and separately imidized. For heating to 280 to 400 ° C. The time required for this imidization is usually about 20 minutes to 3 hours.

  Similarly, when polyamide imide is used as the resin for the base material layer, diamine or diisocyanate derived from diamine and trimellitic acid are reacted in a solvent to directly form polyamide imide, and this is subjected to centrifugal molding to produce a joint. (Seamless) polyamideimide base material layer can be formed. In addition, in order to impart desired semiconductivity to the base material layer, a conductive agent such as carbon black as described above may be added to about 5 to 25 parts by weight with respect to 100 parts by weight of the base material layer resin as necessary. May be added.

  The base material layer formed using centrifugal molding is different from the cylindrical mold used for forming the surface layer and elastic layer described above in terms of the shrinkage rate of the raw material and the heat resistance temperature. It is preferable to use a film-dedicated mold.

  The Young's modulus of the polyimide or polyamideimide thus obtained by centrifugal molding is usually 2500 MPa or more.

  When polycarbonate, PVDF, polyamide, ethylene-tetrafluoroethylene copolymer or the like is used as the material for the base material layer, a seamless base material layer can be formed by melting and extruding these resins. You may add electrically conductive agents, such as above-mentioned carbon black, so that it may become about 5-25 weight part with respect to 100 weight part of base material layer resin.

  The resins that can be extruded are as described above. In this case, in order to maintain the performance as a substrate, a material having a Young's modulus of 1000 MPa or more, preferably 1500 MPa or more can be selected.

The volume resistivity of the base layer, from the viewpoint of performing transfer by electrical control of the toner as a belt substrate, usually 10 ⁴ ~10 ^12.5 Ω · cm approximately, - preferably 10 ⁹ to 10 ^12.5 Omega It is about cm.

As described above, a base material layer having a seamless high strength can be obtained.
Process (2)
In step (2), the elastic layer side of the first belt and the second belt are bonded together to produce a multilayer elastic belt for an electrophotographic apparatus.

  A first belt composed of two layers of an integrated surface layer and an elastic layer and a second belt that is a base material layer made of a high-strength resin material are connected to the inner surface (elastic layer side) of the first belt. And the outer surface of the second belt are in contact with each other. You may apply | coat an adhesive agent and a primer between both as needed. After the superposition of both, it is preferable that the space between the two is sealed. Thereafter, the laminate is heat-treated to obtain an endless three-layer elastic belt in which the inner surface of the elastic layer and the outer surface of the base material layer are bonded.

  Specific examples of the three-layer process will be given. A laminate adhesive is uniformly applied to the inner surface (surface on the elastic layer side) of the two-layer film formed of the surface layer and the elastic layer formed in a state regulated by the inner surface of the cylindrical mold, and air-dried. After applying a primer to the outer surface of the base material layer formed by another dedicated cylindrical mold and air-drying it, the inner layer is superposed on the inner surface of the elastic layer and closely contacts the inner surface of the base material layer so that the position does not shift. Insert a type.

  Examples of the laminating adhesive include Takelac A-969 manufactured by Mitsui Chemicals Polyurethane Co., Ltd. and Tyforce NT-810 manufactured by DIC Co., Ltd. In addition, although use of said primer is arbitrary, it is preferable to use from the point of an adhesive strength improvement. Examples of the primer include DY39-067 manufactured by Toray Dow Corning Co., Ltd.

Thereafter, heat treatment is carried out at about 100 ° C. for about 20 to 60 minutes, and interlayer adhesion is completed simultaneously with the curing of the adhesive. If necessary, the three-layer belt after demolding may be further annealed by heating at about 120 ° C. for about 3 to 5 hours. In this way, a multilayer (three-layer) elastic belt is obtained (see, for example, FIG. 2). The resulting belt is a seamless endless tube.
Step (3)
In the step (3), the indentation depth is fixed from the surface layer of the multilayer elastic belt for an electrophotographic apparatus using a dynamic ultra-micro hardness meter (for example, DUH-211S manufactured by Shimadzu Corporation), and the Martens hardness (HMT115) is measured, and it is confirmed that the value is 5 N / mm ² or less.

  The dynamic ultra-small hardness meter can measure the physical properties of the surface by measuring the relationship between the load and the indentation depth. Specifically, an indenter (standard triangular pyramid indenter 115 °) is pressed against the surface layer of the multilayer elastic belt for an electrophotographic apparatus by electromagnetic force. In the process of pushing the indenter into the surface layer, the indentation depth is automatically measured. In the present invention, this apparatus is used to measure the Martens hardness (HMT115) when the indentation depth from the surface layer reaches a predetermined depth.

It is agreed that the Martens hardness is defined in the ISO standard. In the ISO standard, ISO14577-1 “Instrumentation indentation hardness” specifies a method (Annex A) for obtaining material parameters from the relationship between the test force and the indentation amount of the indenter into the sample. In other words, the Martens hardness (HM) is a hardness measured with a test force applied. From the relationship of the test force-indentation depth curve when the load increases, the test force F is measured from the surface to the indenter. The value is divided by the surface area As that has entered, and the unit is represented by N / mm ² .
Martens hardness (HM) formula:
HM = F / As = 1000 f / 26.43 h ²
f: Test force (mN) h: Indentation depth (μm)
However, in the standard case, a triangular pyramid indenter with a ridge angle of 115 ° is used. Therefore, in the present invention, HM in the above arithmetic expression is expressed as HMT115.

  The Martens hardness in the present invention is measured by fixing the indentation depth of the indenter. Usually, it is fixed in the range of 0.2 to 2 μm, preferably 0.5 to 1.5 μm (see Test Example 2 and FIG. 1). In particular, when the indenter push-in depth is fixed at 1 μm, it is most preferable because it approximates the amount of belt deformation caused by toner during actual use of the belt. Below this range, the Martens hardness is highly dependent on the material hardness of the surface layer and the measurement error is large. If this range is exceeded, the Martens hardness is strongly influenced by the material hardness of the elastic layer. When the indentation depth is within this range, the belt functions as necessary for toner transfer without being affected by the hardness of either the surface layer or the elastic layer (intermediate layer) of the multilayer elastic belt. Can be accurately evaluated by replacing with the value of Martens hardness.

Further, the aim of the hardness of the material constituting the surface layer (Rockwell hardness in R scale conforming to JIS K 7202) and the thickness of the surface layer is not limited to one by the combination thereof. The hardness and thickness of the final multilayer elastic belt are fixed within the above-mentioned predetermined range (about 0.2 to 2 μm, especially about 1 μm) of the dynamic ultra-micro hardness meter from above the surface layer. When the Martens hardness (HMT115) is measured, the value is 5 N / mm ² or less, preferably 3 N / mm ² or less, more preferably 2.7 N / mm ² or less, particularly 0.5 to 2.7 N / mm. It is important to prepare it to be ² .

The hardness of the material constituting the surface layer is preferably 100 degrees or less, more preferably 80 degrees or less, particularly 40 to 80 degrees in terms of Rockwell hardness on the JIS K 7202 compliant R scale. The thickness of the surface layer is 4 μm or less, preferably 0.5 to 3.5 μm, particularly 1 to 3 μm.
The hardness and thickness of the surface layer can be selected from the above range. The thickness can be measured using a non-contact measuring machine such as an electron microscope. The Martens hardness tends to become harder as the Rockwell hardness increases or the thickness increases.

The change in the Martens hardness of the surface layer measured in this way is determined by the primary transfer characteristics of the intermediate transfer belt (the presence or absence of image hollowing, the sharpness of fine line printing), and the secondary transfer characteristics (releasability and cleaning properties, It has a high correlation with the quality of paper irregularity tracking. Specifically, if the Martens hardness of the surface layer is within a predetermined range (5 N / mm ² or less), excellent primary and secondary transfer characteristics are exhibited. As described above, in the present invention, it is possible to grasp the evaluation of the primary and secondary transfer characteristics in relation to the physical numerical value (Martens hardness) of the belt.

For example, by maintaining the Martens hardness of the surface layer of the multilayer elastic belt within a predetermined range (5 N / mm ² or less), a high-quality intermediate transfer belt excellent in primary and secondary transfer characteristics can be manufactured. Alternatively, the primary and secondary transfer characteristics can be appropriately estimated by measuring the Martens hardness of the surface layer of the intermediate transfer belt, whose primary and secondary transfer characteristics are unknown, using the measurement method described above.

  As described above, the multilayer elastic belt of the present invention is suitably used as an electrophotographic belt such as an intermediate transfer belt, a transfer conveyance belt, a paper conveyance belt, or a transfer fixing belt used in an image forming apparatus.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example with a comparative example, this invention is not limited to these Examples.

The evaluation described in this specification was performed as follows.
<Solid content concentration of base material layer>
A sample (a master batch solution of polyamic acid) is precisely weighed in a heat-resistant container such as a metal cup, and the weight of the sample at this time is Ag. Put the heat-resistant container containing the sample in an electric oven, heat and dry while heating up in order of 120 ℃ × 12min, 180 ℃ × 12min, 260 ℃ × 30min, and 300 ℃ × 30min. The weight of the solid content (solid content weight) is Bg. The values of A and B of five samples of the same sample were measured (n = 5) and applied to the following formula (I) to determine the solid content concentration. The average value of the five samples was adopted as the solid content concentration.

Base material layer solid content concentration = B / A x 100 (%) (I)
<Solid content concentration of surface layer and elastic layer>
The raw material of the surface layer or elastic layer is precisely weighed, and the weight of the solid or liquid raw material at this time is Cg. In order to dissolve the raw material in the solvent on the electronic balance, the solvent is gradually added while stirring, and the final solution weight is set to Dg. The solid content concentration is represented by the following formula (II).

Solid content concentration = C / D x 100 (%) (II)
<Thickness>
The thickness was measured as a mean value by measuring a total of 24 points of 3 points in the width direction and 8 points in the circumferential direction using a flat probe of a contact-type film thickness measuring instrument.
<Surface resistivity, volume resistivity>
Surface resistivity (Ω / □) and volume resistivity (Ω · cm) were measured at 23 ° C and 55% RH using a resistance meter “HIRESTA UP / UR Blob” manufactured by Mitsubishi Chemical Corporation. It was measured. A belt cut to a length of 360 mm in the width direction is used as a sample, and the surface resistivity is 10 seconds after an applied voltage of 100 V at a total of 12 points in the width direction of the sample, 3 places at equal pitch and 4 places in the longitudinal (circumferential) direction. The volume resistivity was measured and the average logarithmic value was shown as a common logarithm value. The measurement sample was measured after standing for 12 hours in an environment of 23 ° C. and 55% RH.
<Rubber material hardness>
In accordance with JIS K6253, a durometer A was used to create and evaluate a bulk (lumb) having a thickness of 6 mm from the material constituting the elastic layer.
<Fluorine resin material hardness of surface layer>
According to JIS K7202, the measurement was performed with a Rockwell tester using an R scale.

Example 1
(1) Film formation of the base material layer Under nitrogen flow, 47.6 g of 4,4'-diaminodiphenyl ether (ODA) is added to 488 g of N-methyl-2-pyrrolidone, and kept at 50 ° C. and stirred until completely dissolved. It was. To this solution, 70 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) was gradually added to obtain 605.6 g of a polyamic acid solution. This polyamic acid solution had a number average molecular weight of 17000, a viscosity of 35 poise, and a solid content concentration of 18.0% by weight.

  Next, 21 g of acidic carbon (pH 3.0) and 80 g of N-methyl-2-pyrrolidone were added to 450 g of this polyamic acid solution, and carbon black (CB) was uniformly dispersed with a ball mill. This master batch solution had a solid content concentration of 18.5% by weight and a CB concentration in the solid content of 20.6% by weight.

  And 276g was extract | collected from this solution, the cylindrical metal mold | die for base-material shaping | molding was prepared, and it shape | molded on the following conditions.

  Base mold: A cylindrical mold with an inner diameter of 301.5 mm and a width of 540 mm, with a mirror finish on the inner surface. The mold is placed on two rotating rollers and rotates with the rotation of the rollers. Arranged. For example, see FIG.

  Heating device: A device designed so that a far-infrared heater is disposed on the outer surface of the mold, and the inner surface temperature of the mold is controlled to 120 ° C.

  First, 276 g of the solution was uniformly applied to the inner surface of the mold while the cylindrical mold was rotated, and heating was started. The heating was performed at a temperature of 1 ° C./min up to 120 ° C., and heating was performed at that temperature while maintaining its rotation for 60 minutes.

After completion of the rotation and heating, the mold was removed as it was without cooling, and left in a hot air retention type oven to start heating for imidization. This heating also reached 320 ° C. while gradually raising the temperature. And after heating for 30 minutes at this temperature, it cooled to normal temperature, peeled and took out the semiconductive tubular polyimide belt formed in this metal mold | die inner surface. The belt had a thickness of 82 μm, an outer peripheral length of 944.3 mm, a surface resistivity of 12.72 (logΩ / □), and a volume resistivity of 10.61 (LogΩ · cm).
(2) Surface layer deposition
30 g of PVDF resin (Kayner # 301F, manufactured by Arkema, Rockwell hardness R105) was dissolved in a mixed solvent of 270 g of N, N-dimethylacetamide (DMAc) and 300 g of methyl ethyl ketone (MEK) to prepare a solution having a solid content concentration of 5 w%. .

  And 20g was extract | collected from this solution, and it shape | molded on the following conditions with the surface layer and the metal mold | die for rubber molding.

  Molding device: The surface layer and the rubber molding mold are cylindrical molds with an inner diameter of 301.0 mm and a width of 540 mm, and are mirror-finished. The mold is placed on two rotating rollers. Arranged to rotate with rotation. For example, see FIG.

While the mold was rotated, it was uniformly applied to the inner surface of the mold and heating was started. Heating was performed at 2 ° C./min up to 140 ° C., and heating was continued for 60 minutes while maintaining the rotation. After forming a surface layer on the inner surface of the die, the die was cooled to room temperature. The thickness of the surface layer formed on the inner surface of the mold was measured with an eddy current thickness gauge and found to be 1 μm.
(3) Formation of elastic layer Add 250 g of acidic carbon (pH 3.5) to a solution of 1000 g of polyurethane elastomer (Urehyper RUP, manufactured by DIC Corporation) in 1250 g of xylene. A master batch solution having a partial concentration of 50% by weight and a carbon black (CB) concentration in the solid content of 20% by weight was prepared. 9.0 g of a curing agent CLH-5 (manufactured by DIC Corporation) was added to 209 g of this master batch and stirred.

  This solution was uniformly applied to the inner surface of the surface layer on which the film had been formed in a state where the mold was rotated, and heating was started. Heating was carried out at 2 ° C./min up to 130 ° C., and heating was continued for 60 minutes at that temperature to form an elastic layer on the inner surface of the mold.

As a preliminary test, the rubber hardness of a urethane rubber single film prepared with this urethane rubber masterbatch solution was measured and found to be 44 ° with Type A (JIS K6253).
(4) Bonding of inner surface of elastic layer and outer surface of base material layer After applying primer DY39-067 (manufactured by Toray Dow Corning Co., Ltd.) to the inner surface of the elastic layer formed in (4) above, air-drying, and then dry dry adhesive The polyimide belt (base material layer) of (1) having a thin coating on the outer surface (Takelac A-969 manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) was inserted and overlapped. Next, heating (80 to 100 ° C.) was performed in a state where the substrate was pressure-bonded from the inner surface of the substrate to complete the bonding. The laminated multilayer belt was peeled off from the mold, both ends were cut, and a multilayer belt having a width of 360 mm was collected.

  The multilayer belt had a thickness of 280 μm, an outer peripheral length of 945.0 mm, a surface resistivity of 12.22 (logΩ / □), and a volume resistivity of 11.52 (LogΩ · cm).

Example 2
In Example 1, instead of the PVDF resin (Kayner # 301F) of (2), a VDF-HFP copolymer resin (Kayner # 2821, Arkema), which is a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP). A multilayer belt was produced in the same manner as in Example 1 except that HFP 5 mol% and Rockwell hardness R75) were selected.

Example 3
In Example 1, only the weight charged in the mold of the PVDF resin of (2) was changed. That is, a solution having a solid content concentration of 5 w% was changed from 20 g to 40 g and a film was formed in the same manner. The surface layer thickness of the finished mold inner surface was 2 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 1.

Example 4
In Example 2, only the weight of the VDF-HFP copolymer resin (2) charged into the mold was changed. That is, a solution having a solid content concentration of 5 w% was changed from 20 g to 40 g and a film was formed in the same manner. The surface layer thickness of the finished mold inner surface was 2 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 2.

Example 5
In Example 2, only the weight of the VDF-HFP copolymer resin (2) charged into the mold was changed. That is, a solution having a solid content concentration of 5 w% was changed from 20 g to 14 g and a film was formed in the same manner. The surface layer thickness of the finished mold inner surface was 0.7 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 2.

Example 6
The VDF-HFP copolymer resin used in Example 2 was changed to a material with an increased HFP ratio (Kayner # 2750, manufactured by Arkema, Rockwell hardness R40), and the input weight of the VDF-HFP copolymer resin to the mold was changed. Then, 80 g of the solution having a solid content concentration of 5 w% was added to form a film by the same method. The thickness of the surface layer of the finished mold inner surface was 4 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 2.

Comparative Example 1
In Example 1, only the weight charged in the mold of the PVDF resin of (2) was changed. That is, a solution having a solid content concentration of 5 w% was changed from 20 g to 80 g and a film was formed in the same manner. The thickness of the surface layer of the finished mold inner surface was 4 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 1.

Comparative Example 2
In Example 2, only the weight of the VDF-HFP copolymer resin (2) charged into the mold was changed. That is, a solution having a solid content concentration of 5 w% was changed from 20 g to 80 g and a film was formed in the same manner. The thickness of the surface layer of the finished mold inner surface was 4 μm. Otherwise, a multilayer belt was produced in the same manner as in Example 2.

Test example 1
Results obtained by incorporating the sample multilayer belts of Examples 1 to 4 and Comparative Examples 1 and 2 into a transfer unit and image evaluation, and a dynamic ultra-small hardness meter (DUH-211S manufactured by Shimadzu Corporation) from the surface layer. Table 1 shows Martens hardness (HMT115) values measured at an indentation depth of 1 μm. The Martens hardness conforms to the ISO standard instrumentation indentation hardness (ISO 14577-1).
<Primary and secondary transfer efficiency>
The primary transfer efficiency was determined from the following equation by measuring the toner weight on the photoreceptor before and after transfer. The secondary transfer efficiency was determined from the following equation by measuring the toner weight on the transfer belt before and after transfer.

Transfer efficiency (%) = 100 × [(toner weight before transfer) − (toner weight after transfer)] / (toner weight before transfer)
Each transfer efficiency was evaluated according to the following criteria.
Primary transfer efficiency: higher than 97% “◯”: 95-97% “△”; less than 95% “×”
Secondary transfer efficiency: higher than 95% “◯”: 90-95% “△”; less than 90% “×”
<Thin wire hollow>
The hollow line image was observed on the transfer belt before the secondary transfer and evaluated. The thin line was observed with a laser microscope at a magnification of 300 times with solid images of two colors Y and M parallel to the transfer belt travel direction of about 0.05mm. It was evaluated according to the following criteria.

  ○: There is no void.

  (Triangle | delta): A void is 1-4 places.

×: Five or more hollows are present <Concavity and convexity followability of paper (rough paper transferability)>
Using “Rezak 66” (surface roughness difference of 80 μm, 151 g / m ² ) from Fuji Xerox Office Supply Co. as the paper with large unevenness, solid printing is performed in cyan and the toner on the deepest part (concave part) is judged visually did. The case where no toner was applied and white spots were evaluated as “x”, the case where white spots were slightly white as Δ, and the case where toner was transferred without unevenness was evaluated as “◯”.

In the examples, since the Martens hardness by the dynamic ultra-micro hardness tester is 5 N / mm ² or less, there is no defect in the thin line in the primary transfer, and the followability to the unevenness of the paper in the secondary transfer is also good. Met.

In Comparative Example 1, the Martens hardness measured by the dynamic ultra-micro hardness tester exceeded 5 N / mm ² , and thin line hollowing occurred. This is because the surface layer material itself is hard.

In Comparative Example 2, the material of the surface layer was soft, but because the thickness was thick, the Martens hardness by the dynamic ultra-micro hardness meter exceeded 5 N / mm ² , and the secondary transferability deteriorated. This is because the soft and thick surface layer causes tackiness on the surface, the toner image cannot be released, and transfer to paper cannot be performed successfully. In this case, the coefficient of friction is increased, so that the toner remaining on the surface is poorly cleaned.

As described above, the multilayer intermediate transfer belt of the present invention has a Martens hardness (HMT115) measured at a depth of 1 μm from the surface layer by a dynamic ultra-micro hardness tester, having a value of 5 N / mm ² or less. Makes it possible to achieve an optimal balance of primary transfer characteristics with clear image printing and fine line printing, secondary transfer characteristics with excellent releasability and cleanability, and the ability to follow irregularities on the media surface. It was.

  Even when an intermediate layer made of a soft rubber material is used by measuring the value of Martens hardness (HMT115) by fixing the indentation depth from the surface layer with a dynamic ultra-micro hardness meter. It was found that the difference in the hardness of the layers can be differentiated numerically even after the finished belt. As a result, a reliable management method was obtained in the development and production processes.

Test example 2
FIG. 1 shows the Martens hardness (HMT115) when the indentation depth is changed using the samples of Example 4 and Comparative Example 1. From FIG. 1, it can be seen that the Martens hardness converges at a deep indentation depth and strongly depends on the material hardness of the elastic layer. Therefore, it was found that when the transfer function shown in Table 1 is controlled by replacing the Martens hardness value, the indentation depth is limited to about 0.2 to 2 μm.

It is a graph which shows the relationship of Martens hardness (HMT115) when the indentation depth in the sample of Example 4 and the comparative example 1 is changed. It is a cross-sectional schematic diagram of a three-layer elastic belt. It is a schematic diagram of the apparatus used for film forming of each layer in an Example.

Claims (9)

A method for producing a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in this order from the surface side. And
(1) A first belt consisting of at least two layers, a surface layer containing a releasable material and an elastic layer containing an elastic rubber material, and a second belt consisting of a base material layer containing a high-strength resin material are manufactured separately. The process of
(2) a step of producing a multilayer elastic belt for an electrophotographic apparatus by bonding the elastic layer side of the first belt and the second belt; and (3) the electrophotographic apparatus using a dynamic ultra-micro hardness meter. Confirming that the value of Martens hardness (HMT115) measured by fixing the indentation depth from the surface layer of the multilayer elastic belt is 5 N / mm ² or less,
The manufacturing method characterized by including. The manufacturing method according to claim 1, wherein in (3), the indentation depth is fixed in the range of 0.2 to 2 μm from the surface layer. The process according to claim 1 or 2 thickness of the surface layer is 4μm or less. The manufacturing method according to any one of claims 1 to 3, wherein the surface layer is a layer containing a fluororesin. The manufacturing method according to any one of claims 1 to 4, wherein the elastic layer is a layer containing a polyurethane elastomer. Material polyimide of the base layer, polyamideimide, polycarbonate, PVDF, polyamides, and ethylene - according to any one of claims 1-5 is at least one selected from the group consisting of tetrafluoroethylene copolymer Manufacturing method. The manufacturing method according to any one of claims 1 to 6, wherein the belt has an endless tubular shape. Primary transferability of a multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high-strength resin material in order from the surface side A method for evaluating secondary transferability,
(1) a step of measuring the Martens hardness (HMT115) value by fixing the indentation depth from the surface layer of the multilayer elastic belt for an electrophotographic apparatus using a dynamic ultra-micro hardness meter; and (2) A step of checking whether the Martens hardness value is 5 N / mm ² or less,
Evaluation method including In order from the surface side, from the surface layer side of the multilayer elastic belt for an electrophotographic apparatus comprising at least three layers of a surface layer containing a releasable material, an elastic layer containing an elastic rubber material, and a base material layer containing a high strength resin material. A hardness measurement method (HMT115) in which the indentation depth from the surface layer of the multilayer elastic belt for an electrophotographic apparatus is fixed using a dynamic ultra-micro hardness meter. Measuring method characterized by measuring.

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