HK1170030B - Intermediate transfer belt - Google Patents

Description

Intermediate transfer belt

Technical Field

The present invention relates to an intermediate transfer belt for an image forming apparatus such as a copying machine, a printer, and a facsimile.

Background

For the purpose of improving the quality of an image obtained by an image forming apparatus, an intermediate transfer belt having a rubber elastic layer structure formed of 2 or 3 layers of rubber elastic resin or the like has been proposed (for example, see patent document 1).

The intermediate transfer belt having such a rubber elastic layer is excellent in flexibility, and therefore, a transfer region of the intermediate transfer belt and a photoreceptor or the like in contact therewith can be stably formed, and stress applied to the toner between the intermediate transfer belt and the photoreceptor or the like can be reduced. Therefore, by using the intermediate transfer belt having the rubber elastic layer, it is possible to prevent missing printing of an image (medium pull け), improve the definition of fine line printing, and the like. Further, it is known that when paper having a rough surface (matte paper) is used, the image quality can be prevented from being degraded because the following property to the unevenness of the paper is improved.

In addition, such an intermediate transfer belt that is compatible with high image quality is required to have rubber elasticity in the thickness direction of the belt, and the toner releasability necessary for the transfer belt is also required as an important element. That is, when transferring toner from the surface of the intermediate transfer belt to a medium such as paper, releasability from the toner is required. Therefore, it is not preferable that the rubber elastic layer having adhesiveness to the toner is exposed on the surface of the intermediate transfer belt. Therefore, a resin surface layer having a low friction coefficient and excellent toner releasability is usually provided on the rubber elastic layer (see, for example, fig. 1). It is known that it is effective to make such a surface layer as thin as possible in order to obtain an image with high image quality, and various studies have been made on an intermediate transfer belt having a thin surface layer.

However, in the intermediate transfer belt for an image forming apparatus, when an external force is applied from a sliding member or the like which is in contact with the belt surface such as a paper, a cleaning blade, a roller, or the like, and the surface layer is a thin film, stress applied to the belt is concentrated on the surface layer of the thin film, and there is a problem that the surface layer is cracked or peeled. In addition, when the hardness of the entire belt is increased to solve such a problem, the durability is excellent, but there is a problem that the image quality is degraded.

In this way, it is very difficult to produce a belt having excellent durability against external friction or the like while maintaining a high-quality image in an intermediate transfer belt having a thin surface layer.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3248455

Disclosure of Invention

Problems to be solved by the invention

The main object of the present invention is to provide an intermediate transfer belt for an image forming apparatus, which maintains a high-quality image and has excellent durability against external friction and the like.

Means for solving the problems

The inventors of the present invention have found that an intermediate transfer belt for an image forming apparatus, which comprises a base material layer, a rubber elastic layer and a surface layer, and in which a predetermined amount of a filler is added to the rubber elastic layer, the filler being present unevenly on the surface layer side in the rubber elastic layer, and/or the dynamic ultrafine hardness measured from the surface layer side being 2.5 to 4.5N/mm when the press-in depth is 2 [ mu ] m, can maintain a high-quality image and has excellent durability against external friction and the like²At a penetration depth of 10 μm, 1.0N/mm²The following. In addition, the intermediate transfer belt of the present invention can have a thin surface layer, and therefore, the ability to follow paper irregularities can be further improved. The present invention has been made based on these findings and further research has been conducted.

The invention provides an intermediate transfer belt for an image forming apparatus.

Item 1. an intermediate transfer belt for image forming, comprising at least 3 layers of the above-mentioned intermediate transfer belt for image forming apparatus, laminated in the order of (a) a base material layer made of resin, (b) a rubber or elastomer rubber elastic layer having a thickness of 200 to 400 μm, and (c) a resin surface layer having a thickness of 0.5 to 6 μm,

(i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5-4.5N/mm at an indentation depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The following, and/or

(ii) A filler is added to the rubber elastic layer in an amount of 0.4 to 4.0% by volume fractionThe mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

Item 2 the intermediate transfer belt for image formation according to item 1, wherein (i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5 to 4.5N/mm at a press-in depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The following.

Item 3 the intermediate transfer belt for image formation as described in item 2, further, (ii) a filler is added to the rubber elastic layer in an amount of 0.4 to 4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

Item 4 the intermediate transfer belt for image formation according to item 1, wherein (ii) a filler is added to the rubber elastic layer in an amount of 0.4 to 4.0% by volume fraction, and a mass concentration M of the filler contained in a region extending from an interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

The intermediate transfer belt for image formation as described in any one of the above items 1 to 4, wherein the rubber elastic layer is composed of 2 or more layers having different hardness, and the rubber layer on the surface layer side has a higher a-type hardness than the rubber layer on the base layer side.

The intermediate transfer belt for image formation as described in any one of the above items 1 to 5, wherein the Young's modulus of the surface layer is 300 to 2000 MPa.

The intermediate transfer belt for image formation according to any one of items 1 to 6, wherein an IRHD hardness (JIS K6253) measured from the surface layer side is 82IRHD or less.

An intermediate transfer belt manufacturing method for an image forming apparatus, comprising:

(1) a step of producing a base material layer by centrifugal molding or melt extrusion molding of a resin;

(2) a step of producing a surface layer having a thickness of 0.5 to 6 μm by centrifugally forming a solution obtained by dissolving or swelling a resin in an organic solvent using a cylindrical mold;

(3) forming a 2-layer film by forming a rubber elastic layer material (composition for forming an elastic layer) containing a filler into a rubber elastic layer having a thickness of 200 to 400 μm by centrifugal molding on the inner surface of the surface layer obtained in the above (2); and

(4) and (3) laminating the outer surface of the base material layer obtained in the above (1) and the inner surface of the 2-layer rubber elastic layer obtained in the above (3) and performing a heat treatment.

ADVANTAGEOUS EFFECTS OF INVENTION

The intermediate transfer belt for an image forming apparatus of the present invention can maintain a high-quality image and realize excellent durability by increasing the rubber hardness of only the portion where the rubber elastic layer contacts the surface layer and avoiding concentration of stress on the surface layer.

Therefore, the intermediate transfer belt for an image forming apparatus of the present invention can maintain a high-quality image and has excellent durability, and therefore, can be suitably used as an intermediate transfer belt for an electrophotographic image forming apparatus such as a copying machine (including a color copying machine), a printer, and a facsimile.

Drawings

Fig. 1 is a schematic cross-sectional view of an intermediate transfer belt of the present invention.

Fig. 2 is a schematic view of an apparatus for film formation in the present invention.

Fig. 3 is a schematic illustration of a cross section of a belt.

Fig. 4 is a diagram showing the major axis and the minor axis in the aspect ratio measurement.

Fig. 5 is a cross-sectional SEM photograph of the multilayer tape of example 1.

Description of the symbols

A: a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μm (FIG. 3)

B: a region having a depth of 60 to 80 μm from the interface between the surface layer and the rubber elastic layer toward the base layer (FIG. 3)

C: a region having a depth of 120 to 140 [ mu ] m from the interface between the surface layer and the rubber elastic layer toward the base layer (FIG. 3)

Detailed Description

1. Intermediate transfer belt for image forming apparatus (hereinafter, also referred to as intermediate transfer belt)

The intermediate transfer belt for an image forming apparatus of the present invention relates to an intermediate transfer belt for image formation, comprising:

an intermediate transfer belt for an image forming apparatus, comprising at least 3 layers of a base layer made of a resin, (b) a rubber or elastomer rubber elastic layer having a thickness of 200 to 400 [ mu ] m, and (c) a resin surface layer having a thickness of 0.5 to 6 [ mu ] m, laminated in this order,

(i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5-4.5N/mm at an indentation depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The following, and/or

(ii) The rubber elastic layer is added with a filler in an amount of 0.4-4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface of the surface layer and the rubber elastic layer to the base layer side to the depth of 20 [ mu ] M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

Among the above-described intermediate transfer belts, the intermediate transfer belt having the characteristic of (ii) is referred to as "intermediate transfer belt 1", the intermediate transfer belt having the characteristic of (i) is referred to as "intermediate transfer belt 2", and the intermediate transfer belt having both the characteristics of (i) and (ii) is referred to as "intermediate transfer belt 3".

The intermediate transfer belts 1, 2, and 3 each have a rubber hardness increased only at a portion of the rubber elastic layer in contact with the surface layer, and as a result, concentration of stress on the surface layer can be avoided, and a high-quality image can be maintained, and excellent durability can be achieved.

Hereinafter, the intermediate transfer belts 1, 2, and 3 are described in detail, respectively.

1.1 intermediate transfer Belt 1

The intermediate transfer belt of the present invention is an intermediate transfer belt for an image forming apparatus, comprising:

comprising at least 3 layers of (a) a resin-made base material layer, (b) a rubber or elastomer-made rubber elastic layer having a thickness of 200 to 400 [ mu ] m, and (c) a resin-made surface layer having a thickness of 0.5 to 6 [ mu ] m,

(ii) the rubber elastic layer is added with a filler in an amount of 0.4-4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface of the surface layer and the rubber elastic layer to the base layer side to the depth of 20 [ mu ] M₁With a surface layer and rubberThe mass concentration M of the filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface of the elastic layer to the base material layer side₃Ratio of (M)₁/M₃) Is 1.3 or more.

(a) Substrate layer

The base layer of the intermediate transfer belt 1 of the present invention is made of a material having excellent mechanical properties in order to avoid deformation of the belt due to stress applied during driving. The base layer is a layer in which a conductive agent is dispersed in a resin, and is formed from a base layer-forming composition containing a resin and a conductive agent.

Examples of the resin include polyimide, polyamideimide, polycarbonate, polyvinylidene fluoride (PVdF), ethylene-tetrafluoroethylene copolymer, polyamide, polyphenylene sulfide, and a mixture thereof.

The polyimide can be usually produced by polycondensation of tetracarboxylic dianhydride and diamine or diisocyanate as monomer components by a known method. In general, a base layer forming composition can be prepared by reacting tetracarboxylic dianhydride and diamine in a solvent such as N-methyl-2-pyrrolidone (hereinafter, NMP) to once prepare a polyamic acid solution, and then dispersing a conductive agent described below in the polyamic acid solution.

Examples of the solvent used in this case include aprotic organic polar solvents such as NMP, N-dimethylformamide, N-diethylformamide, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, and 1, 3-dimethyl-2-imidazolidinone, and 1 of these can be used alone or in combination with 2 or more. Among these, NMP is preferable.

Examples of the tetracarboxylic acid dianhydride include pyromellitic acid, 1, 4, 5, 8-naphthalene tetracarboxylic acid, 2, 3, 6, 7-naphthalene tetracarboxylic acid, 2, 3, 5, 6-biphenyl tetracarboxylic acid, 2 ', 3, 3' -biphenyl tetracarboxylic acid, 3, 3 ', 4, 4' -diphenyl ether tetracarboxylic acid, dianhydrides such as 3, 3 ', 4, 4' -benzophenone tetracarboxylic acid, 3 ', 4, 4' -diphenylsulfone tetracarboxylic acid, azobenzene-3, 3 ', 4, 4' -tetracarboxylic acid, bis (2, 3-dicarboxyphenyl) methane, bis (3, 4-dicarboxyphenyl) methane, β -bis (3, 4-dicarboxyphenyl) propane, and β, β -bis (3, 4-dicarboxyphenyl) hexafluoropropane.

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 ' -dimethylbenzidine, 3 ' -dimethoxybenzidine, 3, 4 ' -diaminodiphenyl ether, 4 ' -diaminodiphenyl ether (ODA), 4 ' -diaminodiphenyl sulfide, 3 ' -diaminobenzophenone, 4 ' -diaminodiphenyl sulfone, 4 ' -diaminoazobenzene, 4 ' -diaminodiphenylmethane, β -bis (4-aminophenyl) propane, and the like.

Examples of the diisocyanate include compounds in which an amino group in the diamine component is substituted with an isocyanate group.

The polyamideimide can be produced by polycondensing trimellitic acid and diamine or diisocyanate by a known method. In this case, the same diamine or diisocyanate as the raw material of the polyimide can be used. The solvent used in the polycondensation may be the same solvent as used for the polyimide.

Examples of the conductive agent dispersed in the base material layer include conductive carbon-based materials such as carbon black and graphite; metals or alloys of aluminum, copper alloys, and the like; and conductive metal oxides such as tin oxide, zinc oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite oxide (ATO), indium oxide-tin oxide composite oxide (ITO), and the like, and 1 kind or 2 or more kinds of these fine powders can be used alone or in combination. The conductive agent to be blended in the base material layer is preferably a conductive carbon-based substance, and more preferably carbon black.

The content of the conductive agent may be usually about 5 to 30% by weight in the base material layer (about 5 to 30% by weight in the solid content of the base material layer-forming composition). Thereby imparting conductivity suitable for the intermediate transfer belt to the base material layer.

The solid content concentration of the composition for forming a base layer is preferably 10 to 40 wt%.

Although the method for producing the composition for forming a base layer is not particularly limited, it is preferable to mix the materials using a ball mill or the like after mixing them from the viewpoint of producing a solution composition in which a conductive agent such as carbon black is uniformly dispersed.

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

(b) Rubber elastic layer

The elastic layer in the intermediate transfer belt 1 of the present invention is provided mainly for the purpose of avoiding line missing due to improvement in the following property to the unevenness of paper and stress concentration to the toner at the time of transfer. The rubber elastic layer is formed from an elastic layer-forming composition containing rubber or an elastomer (hereinafter, also referred to as a rubber material).

Examples of the rubber material forming the rubber elastic layer include, but are not particularly limited to, isoprene rubber, butadiene rubber, chloroprene rubber, Styrene Butadiene Rubber (SBR), acrylonitrile butadiene rubber (NBR), silicone rubber, fluorine rubber, butyl rubber (IIR), acrylic rubber (ACM), and urethane rubber. Among these, silicone rubber, fluororubber, butyl rubber, acrylic rubber, and urethane rubber are preferable.

Examples of the silicone rubber include addition type liquid silicone rubber, and specifically, KE-106 and KE1300 manufactured by shin-Etsu chemical Co., Ltd.

Examples of the fluororubber include vinylidene chloride-based Fluororubbers (FKM), tetrafluoroethylene-propylene-based (FEPM), and tetrafluoroethylene-perfluorovinylether-based (FFKM), and specifically include fluororubber coating materials GLS-213F, GLS-223F manufactured by dajin industries, and fluororubber coating materials FFX-401161 manufactured by tai heisha industries.

As the butyl rubber, an isobutylene-isoprene copolymer is exemplified.

The acrylic rubber is a rubbery elastomer obtained by polymerization of an acrylic ester or copolymerization mainly of the acrylic ester.

The polyurethane rubber can be obtained by addition polymerization of a polyol with a diisocyanate. The mixing ratio of the polyol and the diisocyanate as raw materials may be such that 1 equivalent of active hydrogen of the polyol and about 1 to 1.2 equivalents of NCO group of the diisocyanate are mixed. In addition, a prepolymer in which a polyol and a diisocyanate are superposed can be used, and in this case, a diisocyanate, a polyol, or a diamine may be further added to the prepolymer as a curing agent. In addition, in order to prolong the pot life, a blocked prepolymer in which the NCO end of the diisocyanate prepolymer is blocked with a blocking agent may be used. Examples of the urethane rubber include polyester urethane rubber (AU) having an ester bond in the main chain and polyether urethane rubber (EU) having an ether bond in the main chain, and specifically may include URE-HYPER RUP1627 (prepolymer for end-capped polyurethane) manufactured by japan ink corporation.

The type a hardness (JIS K6253) of the rubber material used for the rubber elastic layer is preferably 80 ° or less, and more preferably 30 to 60 °. The type a hardness is a value representing the softness of the rubber. When the type a hardness exceeds 80 °, the elastic layer is too hard, and the tracking property is poor when the paper having irregularities is used, and when the toner is transferred 1 time, the toner adheres at a high concentration, and the phenomenon of missing printing is likely to occur due to stress concentration. On the other hand, if the a-type hardness is less than 30 °, the a-type hardness is too soft, and stress generated during belt driving tends to concentrate on the surface layer, and sufficient durability tends not to be obtained.

The rubber elastic layer of the intermediate transfer belt 1 is characterized in that a filler is added in an amount of 0.4 to 4.0% by volume fraction, and the filler is unevenly present on the surface layer side of the rubber elastic layer. The surface layer side of the rubber elastic layer is a portion within about 20 μm from the surface layer side of the rubber elastic layer.

The amount of the filler added is 0.4 to 4.0%, preferably 0.4 to 3.5%, in terms of volume fraction to the rubber elastic layer. The amount of the rubber or elastomer is preferably 0.8 to 10.0 parts by weight, more preferably 1.0 to 8.0 parts by weight, based on 100 parts by weight of the rubber or elastomer contained in the rubber elastic layer. If the amount of the filler is too large, the hardness of the entire rubber elastic layer tends to be high, and a good image cannot be maintained, and if it is too small, the portion in contact with the surface layer tends to be soft, and concentration of stress on the surface layer tends not to be prevented.

In the intermediate transfer belt 1 of the present invention, the filler is present unevenly on the surface layer side in the rubber elastic layer, but the uneven presence of the filler can be expressed by the ratio of the mass concentration of the filler on the surface layer side in the rubber elastic layer to the mass concentration of the filler at other places. Specifically, the following is shown.

M represents the mass concentration of the filler contained in a region (A in FIG. 3) extending from the interface between the surface layer and the rubber elastic layer toward the base layer to a depth of 20 μ M₁M is the mass concentration of the filler contained in a region (B in FIG. 3) having a depth of 60 to 80 μ M from the interface between the surface layer and the rubber elastic layer toward the base layer side₂M is the mass concentration of the filler contained in a region (C in FIG. 3) having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₃。

The mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Concentration ratio of (M)₁/M₃) Usually 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, and still more preferably3.0 or more, and particularly preferably 3.0 to 30.

The mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 60 to 80 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₂Ratio of (M)₁/M₂) Usually 1.2 or more, preferably 1.4 or more, more preferably 1.5 or more, still more preferably 2.5 or more, and particularly preferably 2.5 to 20.

The above mass concentration ratio (M)₁/M₃、M₁/M₂) The larger the amount of the filler, the more the filler is unevenly present on the surface layer side in the rubber elastic layer. If M is₁/M₃M is 1.3 or more₁/M₂When the rubber hardness is 1.2 or more, the rubber hardness of only the region in contact with the surface layer of the rubber elastic layer is high, and therefore, an intermediate transfer belt having excellent durability and maintaining a high-quality image while avoiding concentration of stress on the surface layer can be obtained. Preferably M₁＞M₂＞M₃。

When the concentration ratio of the filler is within the above range, it means that the filler is unevenly present on the surface layer side in the rubber elastic layer. By thus locally unevenly arranging the filler, the hardness of the entire rubber layer is not increased, and only the hardness of the portion in contact with the surface layer is increased, so that concentration of stress on the surface layer can be prevented, which is preferable.

Here, the mass concentration of the filler was measured by measuring the mass concentration of the main elements constituting the filler by an energy dispersive X-ray analysis apparatus (EDX) (acceleration voltage: 20kV, irradiation time: 5 minutes). For example, when the filler is aluminum borate, the aluminum concentration is measured, and when the filler is mica, the silicon concentration is measured.

In the measurement using EDX, in order to measure a region of 20 μm × 20 μm, a region of 20 μm × 20 μm is arbitrarily measured 3 times for each region (for example, a portion surrounded by a thick line in fig. 3 is measured), and the average value thereof is defined as the filler concentration in the region.

The method of making the filler unevenly exist is not particularly limited, and examples thereof include a method of making a film by forcibly making the filler unevenly exist on the surface layer side by centrifugal molding or the like described later.

Examples of the filler to be blended include aluminum borate, potassium titanate, calcium silicate, boron nitride, aluminum nitride, alumina (alumina), titanium oxide, zirconium oxide, mica, talc, clay, hydrotalcite, silica, (normal) spherical silica, calcium carbonate, magnesium sulfate, zinc oxide, carbon black, PTFE, and the like. Among these, aluminum borate, mica, zirconia, magnesium sulfate, barium sulfate, and spherical silica are preferable. Particular preference is given to particulate zirconium oxide, barium sulfate, aluminum borate and spherical silicon dioxide. The filler may be appropriately treated with a coupling agent or the like depending on the combination of the filler and the rubber elastic layer.

The shape of the filler is not particularly limited. For example, needle-like, granular, spherical, plate-like, fibrous, etc. can be mentioned, and they may be either amorphous or amorphous. In particular, from the viewpoint of reducing the friction coefficient of the belt surface, suppressing the noise of the image after the intermediate transfer, and the like, the granular shape or the spherical shape is preferable.

The filler powder has a volume average particle diameter (median diameter D50) of usually 0.4 to 8 μm, preferably 0.5 to 5 μm, and particularly preferably 0.6 to 4 μm. When the particle diameter is too large, the filler having a large aspect ratio similarly generates a fine hardness distribution on the belt surface, and the image tends to be noisy. When the particle diameter is too small, the filler is difficult to be unevenly distributed on the surface layer side, and therefore, concentration of stress on the surface layer cannot be sufficiently prevented, and the surface layer tends to be cracked.

The average particle diameter of the filler in the rubber elastic layer in the intermediate transfer belt of the present invention can be measured by SEM cross-sectional observation or the like. Since the filler is dispersed in the resin solution to form the rubber elastic layer, a part of the filler aggregates during removal of the solvent, and the average particle size tends to be slightly larger (about 1 to 2 μm) than the average particle size of the filler powder itself in the rubber elastic layer. Therefore, when the filler powder having an average particle diameter of 0.4 to 8 μm is used, the average particle diameter of the filler in the rubber elastic layer is about 1.4 to 10 μm.

The average aspect ratio (major axis/minor axis) of the filler used in the present invention is preferably 5 or less, and more preferably 3 or less. When the filler is a needle-like or plate-like filler having a large average aspect ratio, a fine hardness distribution is generated on the belt surface, and when a halftone image having a low image density is displayed, noise tends to appear. In the present invention, "granular" refers to a shape having an average aspect ratio of more than 1.2 and not more than 3, and "spherical" refers to a shape having an average aspect ratio of 1 to 1.2.

Here, the "average aspect ratio" in the present invention can be measured as follows. The filler was photographed at a magnification of 1000 to 10000 times by an electron microscope (SEM, S-4800, manufactured by Hitachi Ltd.), 1 particle was randomly selected from the particles in the obtained photomicrograph, and the major and minor diameters of the particles were measured by a ruler. The aspect ratio is calculated as the value of the ratio of the measured major axis to minor axis (major axis/minor axis). The same operation was performed for other 19 randomly selected particles, and the average of the aspect ratios of 20 particles in total was defined as the average aspect ratio.

Here, the short diameter is a distance between two parallel lines (dotted lines in fig. 4) that are selected so as to sandwich the filler particle and are in contact with the outer side of the particle, among the two parallel lines, of the filler particle in the micrograph. On the other hand, the long diameter is the distance between two parallel lines (broken lines in fig. 4) spaced the longest in the combination of two parallel lines that are perpendicular to the parallel line that determines the short diameter and two parallel lines that are in contact with the outside of the filler particle. The rectangle formed by these four lines is just as large as the filler particles are contained therein.

In the composition for forming an elastic layer, a curing agent may be added as needed. For example, in the case of silicone rubber, hydrogenated polyorganosiloxane or the like can be used as the curing agent, and in the case of urethane rubber, diisocyanate, polyol or diamine can be used as the curing agent. These curing agents may be used in combination with the rubber elastic layer material.

When the curing agent is added, the amount of the curing agent added may be the same as the amount of the rubber base compound and the curing agent mixed so that the number of reactive functional groups is 1: 1, but when the curing agent is a highly reactive substance such as diisocyanate, the amount is preferably 1 to 1.2 times the amount in terms of the amount of the curing agent added, considering that the reactivity with moisture in the environment is lost.

The solid content concentration of the composition for forming an elastic layer can be appropriately set by the production method, and usually, it is preferable to contain about 20 to 70% by weight of a filler.

The method for producing the composition for forming an elastic layer is not particularly limited, and it is preferable to mix the materials and mix them using a ball mill or the like.

The thickness of the rubber elastic layer is 200 to 400 μm, preferably 200 to 350 μm, and more preferably 200 to 300 μm. When the thickness of the rubber elastic layer is within the above range, the contact pressure between the photoreceptor and the transfer belt can be kept low, toner aggregation on the photoreceptor and a "line missing" phenomenon in which no transfer is made at the center of a linear image can be prevented, and color shift which is likely to occur when the thickness of the transfer belt is too thick can be prevented, which is preferable.

(c) Surface layer

The surface layer of the intermediate transfer belt 1 of the present invention is a layer for carrying a direct toner, transferring the toner to paper, and releasing the toner from the paper, and is required to have excellent surface accuracy. The surface layer is formed of a surface layer material in which a resin is dissolved or dispersed in an organic solvent or water.

Examples of the resin used for the surface layer include polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, Polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether (PFA), a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), a copolymer of tetrafluoroethylene and ethylene (ETFE), polyimide, and polyamideimide. Among these, fluorine-based resins are particularly preferable from the viewpoint of friction coefficient and abrasion resistance, and polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene are particularly preferable from the viewpoint of electrical characteristics.

A layered clay mineral may be added to the surface layer, and examples of the layered clay mineral include montmorillonite and hydrotalcite.

These layered clay minerals may be natural or synthetic. Examples of the synthetic smectites include Kunipia F manufactured by Kunimine industries, Ltd; examples of the synthetic hectorite include Lapnite XLG, Lapnite RD and Lucite STN available from CO-OPchemical Co., Ltd; examples of the synthetic saponite include Smecton SA manufactured by Kunimine industries, and they are commercially available.

1 or more kinds of the above layered clay minerals can be used alone or in combination.

The amount of the layered clay mineral is preferably 0.1 to 5 wt%, more preferably 0.5 to 5 wt%, and still more preferably 1 to 5 wt%, based on the total weight of the surface layer. By blending the layered clay mineral in such a ratio, the occurrence of pinholes is reduced even if the surface layer of the transfer belt is made thin, and excellent rough paper transfer performance and durability can be achieved.

Here, the excellent matte paper transfer performance means a performance of transferring without unevenness such as white leakage or the like when a magenta single color is continuously printed on the entire surface using a paper having a strong unevenness such as a coated paper and adhesion of toner at the deepest portion (concave portion) is visually judged.

The surface layer can be formed by applying a surface layer material obtained by dissolving or swelling the resin and an optionally added lamellar clay mineral in an organic solvent to the inner surface of a cylindrical mold or the like and drying the material.

The organic solvent for dissolving or swelling the resin is not particularly limited, and for example, a mixed organic solvent of an aprotic polar solvent and another organic solvent can be used.

The aprotic polar solvent includes N, N-dimethylacetamide, N-dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, and the like, and 1 kind or 2 or more kinds can be used alone or in combination.

Examples of the other organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; or a mixed solvent thereof.

In the present invention, it is preferable to use, as the surface layer material, a solution obtained by dissolving and swelling a resin and a layered clay mineral in an organic solvent, leaving the solution to stand for about 48 to 72 hours, and then visually observing no sedimentation.

The surface roughness (Rz) of the surface layer is preferably 0.25 to 1.5. mu.m, more preferably 0.4 to 1.3. mu.m, and still more preferably 0.6 to 1.2. mu.m. When the surface roughness is less than 0.25 μm, the surface roughness tends to adhere to sliding members such as rollers to cause excessive torque during driving, and when the surface roughness exceeds 1.5 μm, the surface roughness is not preferable because the surface roughness causes fixing (filming) of toner or image defects such as missing marks. In the present invention, the surface roughness of the surface layer means the surface roughness measured in the surface layer of the intermediate transfer belt of the present invention including the base material layer, the elastic layer, and the surface layer.

The thickness of the surface layer in the present invention is 0.5 to 6 μm, preferably 1 to 4 μm, and more preferably 2 to 4 μm. If the thickness of the surface layer exceeds the above range, the rubber elasticity of the elastic layer is impaired, which is not preferable. If the thickness of the surface layer is less than the above range, problems in durability such as formation of pinholes tend to occur.

The Young's modulus of the surface layer is preferably 300 to 2000MPa, more preferably 500 to 1200 MPa. It is preferable that the young's modulus is 2000MPa or less because the line missing caused by the concentration of stress on the toner can be prevented, and the young's modulus is 300MPa or more because the increase of the friction coefficient of the surface layer can be prevented and the deterioration of the secondary transfer efficiency can be prevented.

The volume resistivity of the surface layer is preferably 1X 10 in general¹²Omega cm or more, more preferably 1X 10¹²～1×10¹⁵Omega. cm, more preferably 1X 10¹²～1×10¹⁴Omega cm. In the present invention, the volume resistivity of the surface layer is a volume resistivity measured on a surface layer monolayer film having a thickness of 10 μm prepared using the composition for forming a surface layer.

1.2 intermediate transfer Belt 2

The intermediate transfer belt 2 of the present invention is characterized in that the dynamic ultramicro hardness measured from the surface layer side is 2.5 to 4.5N/mm when the press-in depth is 2 μm (when the press-in depth is fixed to 2 μm)²When the penetration depth was 10 μm (when the penetration depth was fixed to 10 μm), the measured value was 1.0N/mm²The following. This indicates that the rubber hardness of the portion (portion from the surface layer side to 20 μm) where the rubber elastic layer is in contact with the surface layer is high, and by providing the rubber elastic layer having such rubber hardness, concentration of stress to the surface layer can be avoided, a high-quality image can be maintained, and excellent durability can be achieved.

The dynamic ultrafine hardness can be measured by a method based on ISO14577-1, and for example, can be measured by a dynamic ultrafine hardness tester (DUH-211/DUH-211S, Shimadzu corporation).

In addition, for the dynamic ultrafine hardness, 5 different portions of the same sample were measured, and the average was taken as a value of hardness.

In general, the hardness measurement is a value influenced by the hardness of a portion up to a depth 10 times the depth of indentation. That is, when the indentation depth is 2 μm, the hardness is measured at a depth of about 20 μm from the surface layer. A load speed of 0.1463mN/sec, a measured value of an indentation depth of 2 μm of 2.5 to 4.5N/mm²Preferably 2.5 to 4.2N/mm²More preferably 2.5 to 4.0N/mm². Within the above range, durability that can withstand the 10 ten thousand pass paper test can be obtained.

Further, the hardness was measured at a depth of about 100 μm from the surface layer at a press-in depth of 10 μm. The load rate was 0.1463mN/sec, and the indentation depth was 10 μm, and the measured value was 1.0N/mm²Preferably 0.3 to 1.0N/mm²More preferably 0.5 to 0.9N/mm². Within the above range, an intermediate transfer belt excellent in the ability to prevent "line missing", "rough paper transferability", and the like can be obtained.

(a) Base material layer and (c) surface layer

The base material layer (a) and the surface layer (c) of the intermediate transfer belt 2 of the present invention can be the same as those of the intermediate transfer belt 1.

(b) Rubber elastic layer

The elastic layer in the intermediate transfer belt 2 of the present invention is provided mainly for the purpose of improving the following property to the unevenness of paper and avoiding the missing of lines due to the concentration of stress to the toner at the time of transfer, as in the intermediate transfer belt 1. The rubber elastic layer is formed from an elastic layer-forming composition containing rubber or an elastomer (hereinafter, sometimes referred to as a rubber material).

The rubber material forming the rubber elastic layer can be set to 2.5 to 4.5N/mm when the penetration depth is 2 μm, as long as the dynamic ultrafine hardness measured from the surface layer side²When the press-in depth is 10 μm, the thickness can be set to 1.0N/mm²The following rubber material is not particularly limited. Specifically, the same rubber material as the intermediate transfer belt 1 can be cited.

The type a hardness (JIS K6253) of the rubber material used for the rubber elastic layer is preferably 80 ° or less, and more preferably 30 to 60 °. Here, the type a hardness is a value representing the softness of the rubber. When the type a hardness exceeds 80 °, the elastic layer is too hard, and the tracking property is poor when the paper having irregularities is used, and the phenomenon of missing due to stress concentration is likely to occur when the toner is attached at a high concentration at the time of 1-time transfer. On the other hand, when the a-type hardness is less than 30 °, the material is too soft, and stress generated during belt driving tends to concentrate on the surface layer, and sufficient durability tends not to be obtained.

In addition, a filler can be added to the composition for forming the elastic layer of the intermediate transfer belt 2, and it is preferable that the filler is unevenly present on the surface layer side in the rubber elastic layer, as in the case of the intermediate transfer belt 1.

When a filler is added to the composition for forming the elastic layer of the intermediate transfer belt 2, the mass concentration M of the filler contained in a region (A in FIG. 3) extending from the interface between the surface layer and the rubber elastic layer toward the base layer to a depth of 20 μ M₁And a mass concentration M of the filler contained in a region (B in FIG. 3) having a depth of 60 to 80 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₂And a mass concentration M of the filler contained in a region (C in FIG. 3) having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₃Concentration ratio of (M)₁/M₂、M₁/M₃) In the following range.

The mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Concentration ratio of (M)₁/M₃) Usually 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, still more preferably 3.0 or more, and particularly preferably 3.0 to 30.

The mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μ M₁And a filler contained in a region having a depth of 60 to 80 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₂Ratio of (M)₁/M₂) Usually 1.2 or more, preferably 1.4 or more, more preferably 1.5 or more, still more preferably 2.5 or more, and particularly preferably 2.5 to 20.

The above mass concentration ratio (M)₁/M₃、M₁/M₂) The larger the amount of the filler, the more the filler is unevenly present on the surface layer side in the rubber elastic layer. If M is₁/M₃Is 1.3 or more, M₁/M₂When the rubber hardness is 1.2 or more, the rubber hardness of only the region in contact with the surface layer of the rubber elastic layer is high, and therefore, an intermediate transfer belt having excellent durability can be obtained while avoiding concentration of stress on the surface layer and maintaining a high-quality image. Preferably M₁＞M₂＞M₃。

Here, the mass concentration of the filler is the same as that defined in the intermediate transfer belt 1, and the method of measuring the mass concentration, the method of making the filler unevenly exist, and the like are also the same as those of the intermediate transfer belt 1.

The amount of the filler added is preferably 0.8 to 10.0 parts by weight, more preferably 1.0 to 8.0 parts by weight, based on 100 parts by weight of the rubber or elastomer contained in the rubber elastic layer. The volume fraction of the rubber elastic layer is preferably 0.2 to 5.0%, more preferably 0.3 to 4.5%, and still more preferably 0.4 to 4.0%. If the amount of the filler is too large, the hardness of the entire rubber elastic layer tends to be high, and a good image cannot be maintained, and if it is too small, the portion in contact with the surface layer tends to be soft, and concentration of stress on the surface layer tends not to be prevented.

As the filler to be compounded, the same fillers as those listed in the intermediate transfer belt 1 can be listed.

In addition, a curing agent may be added to the composition for forming an elastic layer, if necessary. For example, in the case of silicone rubber, hydrogenated polyorganosiloxane or the like can be used as the curing agent, and in the case of urethane rubber, diisocyanate, polyol or diamine can be used as the curing agent. These curing agents may be used in combination with the rubber elastic layer material.

When the curing agent is added, the amount of the curing agent added may be the same as the amount of the rubber base compound and the curing agent since the number of reactive functional groups is 1: 1, but in the case of a highly reactive substance such as diisocyanate, the amount is preferably 1 to 1.2 times the amount in terms of the amount of the curing agent added, considering that the substance loses activity due to reaction with moisture in the environment, etc.

The solid content concentration of the composition for forming an elastic layer can be appropriately set according to the production method, and generally, it is preferable to contain about 20 to 70% by weight of a filler.

The method for producing the composition for forming an elastic layer is not particularly limited, and it is preferable to mix the materials and mix them using a ball mill or the like.

The rubber elastic layer may be formed of 2 or more rubber layers having different hardness. For example, in the case of an n-layer rubber layer, the 1 st rubber layer, the 2 nd rubber layer, …, and the nth rubber layer (the rubber layer closest to the base material layer) are provided from the rubber layer closest to the surface layer. In this case, the type a hardness of the 1 st rubber layer is preferably the highest and is preferably smaller toward the base layer side. For example, when the rubber layer is composed of 2 layers, it is preferable that the 1 st rubber layer on the surface layer side is 5 to 50 μm, the A-type hardness is 70 to 95 °, the 2 nd rubber layer on the base layer side is 95 to 350 μm, and the A-type hardness is 30 to 60 °.

The thickness of the rubber elastic layer is 200 to 400 μm, preferably 200 to 350 μm, and more preferably 200 to 300 μm. When the thickness of the rubber elastic layer is within the above range, the contact pressure between the photoreceptor and the transfer belt can be kept low, toner aggregation on the photoreceptor and a "line missing" phenomenon in which no transfer is made at the center of a linear image can be prevented, and color shift which is likely to occur when the thickness of the transfer belt is too thick can be prevented, which is preferable.

1.3 intermediate transfer Belt 3

The intermediate transfer belt 3 of the present invention has both the features (i) and (ii) of the intermediate transfer belts 1 and 2 described above. That is, the intermediate transfer belts 1 and 2 described above have various configurations. Therefore, the intermediate transfer belt 3 can achieve excellent effects equivalent to or more than those of the intermediate transfer belts 1 and 2.

1.4 values of physical properties of intermediate transfer Belt

The intermediate transfer belt of the present invention has the following physical property values.

(IRHD hardness of intermediate transfer Belt)

The intermediate transfer belt preferably has an IRHD hardness of 82IRHD or less, more preferably 50 to 82 IRHD. Within the above range, an intermediate transfer belt having excellent "rough paper transferability" can be obtained. The IRHD hardness can be measured according to JIS K6253.

(surface roughness of intermediate transfer Belt)

The intermediate transfer belt of the present invention has a high surface accuracy, and the surface roughness of the surface layer is preferably about 0.25 to 1.5 μm, more preferably about 0.4 to 1.3 μm, and still more preferably about 0.6 to 1.2 μm in terms of ten-point average roughness (Rz: JIS B0601-1994).

(coefficient of static friction and volume resistivity of surface of intermediate transfer Belt)

The surface of the intermediate transfer belt of the present invention preferably has a static friction coefficient of 0.1 to 1, more preferably about 0.2 to 0.8, and still more preferably 0.2 to 0.4. In addition, the surface resistivity of the intermediate transfer belt of the present invention is preferably 1 × 10¹⁰～1×10¹⁵Omega/□, the volume resistivity is preferably 1X 10⁸～1×10¹⁴The range may vary depending on the amount of the conductive agent added to the elastic layer and/or the base layer.

The average total thickness of the intermediate transfer belt of the present invention is usually about 100 to 400 μm, preferably about 150 to 350 μm. The thickness of each layer can be appropriately set in consideration of the stress applied to the belt and the flexibility at the time of driving, and the ratio of the thickness of each layer is usually about 1.5 to 5.0, preferably about 2 to 4, for the elastic layer when the base material layer is 1; the surface layer is about 0.005-0.05. By adopting such a 3-layer process, a uniform tape with small variations in thickness can be produced.

2. Method for manufacturing intermediate transfer belt for image forming apparatus

The method for producing the intermediate transfer belt for an image forming apparatus having the above-described configuration is not particularly limited, and examples thereof include the following methods.

The intermediate transfer belt for an image forming apparatus of the present invention can be obtained by a manufacturing method including the following steps.

(1) A step of producing a base material layer by centrifugal molding or melt extrusion molding of a resin;

(2) a step of producing a surface layer having a thickness of 0.5 to 6 μm by centrifugally forming a solution obtained by dissolving or swelling a resin in an organic solvent using a cylindrical mold;

(3) forming a 2-layer film by forming a rubber elastic layer material (composition for forming an elastic layer) containing a filler into a rubber elastic layer having a thickness of 200 to 400 μm by centrifugal molding on the inner surface of the surface layer obtained in the above (2); and

(4) and (3) laminating the outer surface of the base material layer obtained in the above (1) and the inner surface of the 2-layer rubber elastic layer obtained in the above (3) and performing a heat treatment.

Alternatively, the elastic sheet can be produced by (1) and (2) preparing a surface layer and a base material layer, respectively, and then (3') laminating the outer surface of the base material layer on the inner surface of the surface layer, injecting the elastic layer material between the both layers, and performing a heat treatment.

The respective steps are explained below. The raw materials used in the production method of the present invention, the contents thereof, and the like are as described above.

Step (1) (formation of substrate layer)

The substrate layer can be manufactured as follows.

First, a case of using polyimide as a typical material of the base material layer will be described.

As described above, tetracarboxylic dianhydride and diamine, which are raw materials of polyimide, are reacted in a solvent such as NMP to once form a polyamic acid solution, and a conductive agent such as carbon black is added to the polyamic acid solution in order to impart a desired semiconductivity to the base layer, thereby preparing a carbon black-dispersed polyamic acid (base layer forming composition).

The obtained composition for forming a base layer is subjected to centrifugal molding using a rotary drum (cylindrical mold) or the like. During heating, the temperature of the inner surface of the drum is slowly raised to about 100 to 190 ℃, preferably about 110 to 130 ℃ (heating stage 1). The temperature rise rate may be, for example, about 1 to 2 ℃/min. The temperature is maintained for 20 minutes to 3 hours, and about half or more of the solvent is volatilized to form a self-supporting tubular belt.

In addition, the rotation speed of the rotary drum in the 1 st heating stage is preferably a centrifugal acceleration which is 0.5 to 10 times of the gravitational acceleration. The typical gravitational acceleration (g) is 9.8 (m/s)²)。

The centrifugal acceleration (G) is derived from the following formula (I).

G(m/s²)＝r·ω²＝r·(2·π·n)²(I)

Here, r represents the radius (m) of the cylindrical die, ω represents the angular velocity (rad/s), and n represents the number of revolutions for 1 second (the number of revolutions for 60 seconds is rpm). The rotation condition of the cylindrical die can be appropriately set by the above formula (I).

Then, the imidization is completed by heating at about 280 to 400 ℃ and preferably about 300 to 380 ℃ as the stage 2 heating. In this case, the temperature is not reached all at once from the stage 1 heating temperature, but is desirably increased gradually to reach this temperature. The heating in the 2 nd stage may be performed in a state where the tubular belt is adhered to the inner surface of the rotary drum, or after the 1 st heating stage is completed, the tubular belt may be peeled off from the rotary drum and supplied to a heating unit for imidization, and heated to 280 to 400 ℃. The time required for the imidization is usually about 20 minutes to 3 hours.

When polyamideimide is used as a material for the substrate layer, a diamine or a diisocyanate derived from a diamine is reacted with trimellitic acid in a solvent to directly obtain polyamideimide, and the polyamideimide is centrifugally molded to obtain a (seamless) polyamideimide substrate layer having no seams.

When polycarbonate, PVdF, an ethylene-tetrafluoroethylene copolymer, polyamide, polyphenylene sulfide, or the like is used as a material of the base layer, a seamless base layer can be produced by melt extrusion molding of these resins.

In this way, a base material layer having no seam can be produced.

Step (2) (formation of surface layer)

The surface layer can be formed, for example, as follows.

The surface layer forming composition is centrifugally molded using a cylindrical mold having a surface roughness (Rz) of 0.25 to 1.5 [ mu ] m. In this case, the thickness of the surface layer obtained is about 0.5 to 6 μm.

The centrifugal molding of the surface layer is carried out, for example, by injecting a surface layer-forming composition in an amount corresponding to a final thickness obtained on the inner surface of a rotating drum (cylindrical mold) rotating at a centrifugal acceleration of 0.5 to 10 times the gravitational acceleration, then gradually raising the rotation speed, increasing the rotation at a centrifugal acceleration of 2 to 20 times the gravitational acceleration, and uniformly casting the entire inner surface by centrifugal force.

In the rotating drum, the inner surface thereof is ground to a prescribed surface accuracy, and the surface state of the rotating drum is transferred almost to the outside of the surface layer of the intermediate transfer belt of the present invention. Therefore, by controlling the surface roughness of the inner surface of the rotating drum, the surface roughness of the surface layer can be adjusted to a desired range. When the average surface roughness (Rz) of the inner surface of the rotary drum is set to be in the range of 0.25 to 1.5 μm, a surface layer having a surface roughness (Rz) of 0.25 to 1.5 μm substantially corresponding thereto can be formed. However, since the surface roughness of the surface layer of the intermediate transfer belt is measured by subtle bending or undulation of the belt, it is easy to form a value slightly higher than the average surface roughness (Rz) of the inner surface of the rotating drum. Therefore, for the required surface roughness of the belt surface layer, a rotating drum having a slightly smaller average surface roughness (Rz) of the inner surface can be employed. The roughness of the inner surface of the mold to be used can be arbitrarily controlled by the type of the polishing paper to be used when the inner surface is finished.

The rotating drum is placed on a rotating roller and indirectly rotated by the rotation of the roller. The size of the drum can be appropriately selected according to the size of the intermediate transfer belt required.

The heating is performed by indirect heating around the drum, for example, from the outside of a heat source such as a far infrared heater. The heating temperature may vary depending on the type of the resin, and generally, when the temperature is from room temperature to around the melting point of the resin, for example, when the melting point Tm of the resin is used, the temperature may be gradually increased to about (Tm ± 40) ° c, preferably to about (Tm-40) ° c to Tm ℃, and the temperature after the temperature increase may be heated for about 10 to 60 minutes. This enables a seamless (seamless) tubular surface layer to be produced on the inner surface of the drum.

Step (3) (2-layer formation)

The elastic layer material was centrifugally formed on the inner surface of the surface layer obtained in the step (2) to form a film of the obtained elastic layer, thereby obtaining a 2-layer film.

The composition for forming an elastic layer is uniformly applied to the inner surface of the surface layer of a rotating drum (cylindrical mold) having a surface layer formed thereon, and then subjected to centrifugal molding, and then heated while rotating the rotating drum at a centrifugal acceleration of 2 to 20 times (preferably 4 to 20 times) the gravitational acceleration. During heating, the temperature of the inner surface of the drum is slowly raised to about 90-180 ℃, preferably about 90-150 ℃. The temperature rise rate may be, for example, about 1 to 3 ℃/min. The above temperature was maintained for 20 minutes to 3 hours, and the surface layer and the 2-layer film having the elastic layer thereon were molded in the drum.

When the rubber elastic layer is 2 layers, the material of the elastic layer is further centrifugally molded on the inner surface of the previously formed rubber elastic layer, and is similarly cured by heating.

Step (4) (3-layer formation)

The outer surface of the base material layer obtained in the step (1) was laminated on the inner surface of the elastic layer of the 2-layer film (surface layer and elastic layer) obtained in the step (3), and heat treatment was performed.

Specifically, a known primer for adhesion or the like is applied to the inner surface of the 2-layer elastic layer formed in the rotary drum and air-dried, and then a base layer coated with a dry lamination adhesive or the like is inserted and laminated to the outer surface. And (3) pressing and sticking the two overlapped layers from the inner surface of the belt, and slowly heating the inner surface of the cylindrical mold to about 40-120 ℃, preferably about 50-90 ℃.

The temperature rise rate may be, for example, about 1 to 10 ℃/min. Maintaining the temperature for 2 to 30 minutes, and molding a 3-layer belt having a surface layer, an elastic layer and a base material layer in a cylindrical mold.

The adhered 3-layer belt was peeled off from the cylindrical mold, and both ends were cut to a desired width to produce a 3-layer intermediate transfer belt.

In the above production method, instead of the steps (3) and (4), the outer surface of the base material layer is laminated on the inner surface of the surface layer, and the elastic layer material is injected between the two layers to perform heat treatment and simultaneously perform film formation and 3-layer formation of the elastic layer (step (3')).

Step (3') (film formation and formation of 3 layers of elastic layer)

The surface layer and the base material layer prepared in the above steps (1) and (2) are laminated so that the inner surface of the surface layer and the outer surface of the base material layer are in contact with each other, and the elastic layer material is injected between the two layers by injection molding. In this case, in order to uniformize the elastic layer, it is preferable to perform ironing from one end portion to the other end portion of the inner surface of the base material layer. The intermediate transfer belt can be obtained by heat-treating the obtained laminate. After the two layers are laminated, the space between the two layers is preferably sealed.

For example, when a silicone rubber is used as the rubber elastic resin, the laminate obtained by injection molding is subjected to a heat treatment at about 110 to 220 ℃, thereby vulcanizing (crosslinking and curing) the elastic layer material and firmly bonding the surface layer and the base layer together.

When the rubber elastic resin is urethane rubber, it is preferable to use both solutions in a mixed state before film formation.

Specific examples of the 3-layer formation step are described above.

The inner surface of the surface layer formed on the inner surface of the drum is uniformly coated with a known adhesive primer or the like and air-dried. The primer is also applied to the outer surface of the produced base material layer, and the laminate is laminated with the inner surface of the surface layer, and the O-rings are pressed against both ends of the tubular tape from the inside in a reduced pressure state, thereby sealing the laminated surface layer and base material layer. Next, the above-mentioned composition for forming an elastic layer was injected into the gap between the two layers by an injection molding method, and the composition for forming an elastic layer was cast from the inner surface side of the base material layer so as to be uniformly distributed in the circumferential direction by using a metal roll.

Alternatively, the following method may be mentioned as another embodiment.

The inner surface of the surface layer formed on the inner surface of the drum is uniformly coated with a known primer for adhesion. After the primer was applied to the outer surface of the prepared base material layer, the outer surface of the cylindrical core was covered with the primer. The core is inserted into the inner surface of a drum having a surface layer formed on the inner surface, and the core and the drum are fixed to a concentric shaft. Then, a paste-like composition for forming an elastic layer was injected into the gap between the two layers from the drum side by an injection molding method. The drum is fixed by a pair of clamps to be sandwiched in the longitudinal direction, one clamp is provided with an inlet for the elastic layer material, and the other clamp is provided with an outlet for the elastic layer material.

The heat treatment after the formation of 3 layers is performed by heating slowly to 110 to 220 ℃ (for example, the heating rate is about 1 to 3 ℃/min), and the treatment is performed at that temperature for 0.5 to 4 hours. Thereby, the tie tape is crosslinked and cured. After the heating, the drum was cooled, and the 3-layered tubular belt was peeled from the inner surface of the drum, thereby obtaining the intermediate transfer belt of the present invention.

The adhesive primer is used as desired, but is preferably used from the viewpoint of improving adhesive strength. Examples of the primer for adhesion include primer DY39-067 manufactured by Dow Corning Toray.

The intermediate transfer belt of the present invention obtained by the above method is excellent in durability while maintaining a high-quality image, and therefore can be suitably used as an intermediate transfer belt for an electrophotographic image forming apparatus such as a copying machine (including a color copying machine), a printer, and a facsimile machine.

Examples

The present invention will be described in further detail below by showing test examples and the like, but the present invention is not limited to these.

The following measurement methods relating to the respective physical property values are shown.

< surface roughness >

The surface roughness (. mu.m) was measured in accordance with JIS B0601-1994. The measurement machine used a laser microscope VK-9700 manufactured by Keyence under the observation conditions of 20 times the objective lens and 1000 times the eyepiece lens 50 times. Using the image of the belt surface obtained by observation, the line thickness was measured under the following measurement conditions.

And (3) inclination correction: face tilt correction (automatic)

Cutoff: is free of

Measuring length: 0.25 mm.

The surface roughness was determined as the average of ten-point average roughness (Rz) at different surface portions in 5 of the same band.

< coefficient of static Friction >

As the coefficient of static friction, different surface sites at 10 positions in the same band were measured using Heidon 94i manufactured by New eastern science, Ltd. and the average value thereof was used as the coefficient of static friction.

< surface resistivity, volume resistivity >

The surface resistivity (Ω/□) and the volume resistivity (Ω · cm) were measured by using a resistance measuring instrument "Hiresta IP · HR probe" manufactured by mitsubishi chemical corporation. A tape cut to have a length of 360mm in the width direction was used as a sample, and a voltage of 100V was applied to 3 points of the sample at equal intervals in the width direction and 12 points in total of 4 points in the vertical (loop) direction, and after 10 seconds, the surface resistivity and the volume resistivity were measured and expressed as average values thereof.

< Young's modulus >

Young's modulus was measured according to JIS K7127 using Autograph AG-X manufactured by Shimadzu corporation.

Sample piece 25X 250mm short strip

Drawing speed 20 mm/min

< dynamic micro hardness >

The hardness was measured under the following conditions using a dynamic ultramicro hardness tester (DUH-211S Shimadzu corporation) at indentation depths of 2 μm and 10 μm. Further, the hardness at each penetration depth was measured at different surface portions in the same band 5, and the average value thereof was defined as the dynamic micro hardness.

Testing machine: shimadzu dynamic ultramicro hardness tester DUH-211S

Test mode: load-unload test

Load speed: 0.1463mN/s

Minimum test force: 0.02mN

Load retention time: 2 seconds

With correction of Cf-Ap, As

The types of indenters: triangular115 (115 degree diamond Triangular pyramid indenter between edges, Berkovich type)

< confirmation of non-uniform Presence of Filler >

The cut surface of the tape was sliced by a microtome, and a sample for observation was prepared by performing gold vapor deposition with a vapor deposition thickness of 5 nm. The observation sample was observed in a cross section by an electron microscope (SEM: S-4800, Hitachi, Ltd.).

Further, the mass concentration M of the filler contained in a region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μ M was measured by EDX (energy dispersive X-ray analysis apparatus EMAX model 7593H manufactured by horiba, accelerated voltage: 20kV, irradiation time: 5 minutes)₁And a mass concentration M of the filler contained in a region having a depth of 60 to 80 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₂And a mass concentration M of the filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer side₃The concentration ratio (M) was obtained₁/M₂、M₁/M₃)。

The mass concentration of the filler measured by EDX was measured by measuring the mass concentration of the main elements constituting the filler (aluminum concentration in the case of aluminum borate, silicon concentration in the case of mica, and zirconium concentration in the case of zirconia). In this case, for observation, the mass concentration of gold deposited was subtracted from the total mass concentration, and the total mass concentration of gold other than gold was defined as 100%. Further, in each region, a 20 μm × 20 μm region was arbitrarily measured 3 times by EDX measurement, and the average value was defined as the filler concentration in the region.

Example 1

(1) Film formation of substrate layer

47.6g of 4, 4' -diaminodiphenyl ether (ODA) was added to 488g N-methyl-2-pyrrolidone under nitrogen flow, and the mixture was kept at 50 ℃ and stirred to be completely dissolved. To this solution, 70g of 3, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride (BPDA) was slowly added to obtain 605.6g of a polyamic acid solution. The polyamic acid solution had a number average molecular weight of 19000, a viscosity of 40 poise and a solid content concentration of 18.1 wt%.

Then, to 450g of the polyamic acid solution, 21g of an acidic carbon black (pH3.0) and 80g N-methyl-2-pyrrolidone were added, and uniform dispersion of Carbon Black (CB) was carried out by a ball mill. The master batch solution had a solid content concentration of 18.6 wt%, and the CB concentration in the solid content was 20.5 wt%.

Then 273g of the solution was taken out and poured into a rotary drum, and molded under the following conditions.

Rotating the drum: the inner surface mirror-finished metal drum having an inner diameter of 301.5mm and a width of 540mm was placed on 2 rotating rolls and was arranged so as to rotate together with the rotation of the rolls (see, for example, fig. 2).

Heating temperature: a far infrared heater is disposed on the outer surface of the drum, and the temperature of the inner surface of the drum is controlled to 120 ℃.

First, 273g of the solution was uniformly applied to the inner surface of the drum while the rotary drum was rotated, and heating was started. The temperature was raised to 120 ℃ at 1 ℃ per minute, and the rotation was maintained at this temperature for 60 minutes and heating was carried out.

After the completion of the rotation and heating, the rotary drum was directly detached without cooling, and was allowed to stand in a hot air convection oven to start heating for imidization. The heating also slowly increased the temperature to 320 ℃. Then, the resultant was heated at this temperature for 30 minutes, cooled to room temperature, and peeled off to take out the semiconductive tubular polyimide tape formed on the inner surface of the drum. Furthermore, the thickness of the tape was 79 μm, outsideA circumference of 944.3mm and a surface resistivity of 2X 10¹¹～4×10¹¹Omega/□, volume resistivity of 1X 10⁹～3×10⁹Ω·cm。

(2) Film formation of surface layer

100g of VdF-HFP co-polymerized resin (KYNAR #2821, manufactured by ARKEMA: HFP11 mol%) which was a copolymer of vinylidene fluoride (VdF) and Hexafluoropropylene (HFP) was dissolved in 900g N, N-dimethylacetamide (DMAc) to prepare a solution A having a solid content of 10 wt%.

To 900g of dimethylacetamide was added 100g of organically modified montmorillonite (LucentitesSTN, manufactured by CO-OP Chemical Co., Ltd.), and the mixture was uniformly dispersed by a ball mill to prepare a solution B having a solid content concentration of 10% by weight.

A solution A and a solution B were mixed by a paint shaker so that the ratio of A to B was 99: 1, and a solution having a solid content of 10% by weight and an organic modified montmorillonite content of 1% by weight was obtained. This was diluted with a mixed solvent of DMAc and butyl acetate at a ratio of 1: 2 to prepare a solution (hereinafter, also referred to as a surface layer material) having a solid content of 1.6 wt% and a concentration of the organically modified montmorillonite in the solid content of 1 wt% (corresponding to a blending ratio of montmorillonite to the total weight of the surface layer). 112g of this solution was formed into a film under the following conditions.

Rotating the drum: a metal drum having an inner diameter of 301.0mm, a width of 540mm, and an inner surface ten-point average roughness (Rz) of 0.5 μm was placed on 2 rotating rolls and was arranged so as to rotate together with the rotation of the rolls (see, for example, fig. 2).

The inner surface of the drum was uniformly coated while the rotary drum was rotated, and heating was started. The heating was carried out while raising the temperature to 130 ℃ at 2 ℃/min, and the rotation was maintained at this temperature for 20 minutes, and the drum was cooled to room temperature after the surface layer was formed on the inner surface of the drum. The thickness of the surface layer formed on the inner surface of the drum was measured by an eddy current type thickness meter (manufactured by Kett chemical research Co., Ltd.) and found to be 2 μm.

Further, use of the aboveThe surface layer material of (2) was separately prepared into a surface layer of 10 μm under the same film forming conditions. The volume resistance value of the 10 μm surface layer was 4X 10¹²Ω · cm, Young's modulus 610MPa, surface roughness (Rz) of the surface layer was 0.6. mu.m.

(3) Production of elastic layer

In a solution obtained by dissolving 141.3g of a prepolymer for a blocked polyurethane (URE-HYPER RUP1627, manufactured by japan ink corporation) in 188g of toluene, 1.52g of whisker-like aluminum borate (Arborex, average particle size DD50 is 8 μm, manufactured by four nations chemical industry corporation) was added as a filler, and the mixture was uniformly dispersed by a ball mill. To the dispersion was added 11.07g of aliphatic diamine-based curing agent CLH-5 (manufactured by Dainippon ink Co., Ltd.) and the mixture was stirred.

The solution thus obtained had a solid content concentration of 45% by weight, and the aluminum borate in the solid content was 1.0% by weight and 0.4% by volume fraction. The dispersion was uniformly applied to the inner surface of the surface layer prepared in advance while rotating, and heating was started. The temperature was raised to 150 ℃ at 1 ℃/min, and the drum was rotated and heated while maintaining the temperature for 30 minutes, thereby forming a rubber elastic layer on the inner surface of the drum.

The rotational speed of the rotating drum in this heating phase is 7.4 times the centrifugal acceleration of the gravitational acceleration.

In general, the acceleration of gravity (g) is 9.8 (m/s)²)。

The centrifugal acceleration (G) is derived from the following formula (I).

G(m/s²)＝r·ω²＝r·(2·π·n)²(I)

Here, r represents the radius (m) of the cylindrical die, ω represents the angular velocity (rad/s), and n represents the number of revolutions for 1 second (the number of revolutions for 60 seconds is rpm). According to the formula (I), the rotation condition of the cylindrical die can be appropriately set.

The thickness of the resulting rubber elastic layer was 248 μm.

A single layer film of a rubber elastic layer was produced in the same manner as described above except that no filler was added to the polyurethane raw material solution for an elastic layer, and the film was laminated to a thickness of 10mm, and the type a hardness was measured, and found to be 40 °.

(4) Adhesion of the inner face of the rubber elastic layer to the outer face of the polyimide

A primer DY39-067 (manufactured by Dow Corning Toray) was applied to the inside surface of the rubber elastic layer formed by the above-mentioned (3), and after air-drying, a polyimide tape (1) coated with a thin dry lamination adhesive on the outside surface was inserted and laminated. Pressing and bonding the substrate layer from the inner surface of the substrate layer, and heating (80-100 ℃) to finish bonding. The bonded multilayer tape was peeled off from the die, and both ends were cut to obtain a multilayer tape having a width of 360 mm.

The multilayer tape had a thickness of 330 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.33, and a surface resistivity of 2X 10¹¹～4×10¹¹Omega/□, volume resistivity of 6X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) (FIGS. 5(a) to (d)) and EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝6.2、M₁/M₃14.1. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 2

A multilayer tape was produced in the same manner as in example 1, except that the amount of aluminum borate blended in the rubber layer was 5% by weight and the volume fraction was 1.96%.

The resulting multilayer tape had a thickness of 334 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.29 and a surface resistivity of 2X 10¹¹～4×10¹¹Omega/□, volume resistanceThe ratio is 6X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝12.5、M₁/M₃24.8. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 3

A multilayer tape was produced in the same manner as in example 1, except that the shape of the aluminum borate blended in the rubber layer was changed to a granular shape (the alumina average particle diameter D50 was 2.6 μm, manufactured by seiko chemical industries, ltd.), the amount thereof was 5 wt%, and the volume fraction thereof was 1.96%.

The resulting multilayer tape had a thickness of 337 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.29 and a surface resistivity of 2X 10¹¹～4×10¹¹Omega/□, volume resistivity of 8X 10¹⁰～1×10¹¹Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝11.5、M₁/M₃13.7. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 4

A multilayer tape was produced in the same manner as in example 1, except that the filler blended in the rubber layer was mica (Somashifu MTE average particle diameter D50 was 6.0 μm, manufactured by CO-OP Chemical corporation), the amount thereof was 5.0% by weight, and the volume fraction was 2.17%.

The resulting multilayer tape had a thickness of 341 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.31, and a surface resistivity of 5X 10¹⁰～7×10¹⁰Omega/□, volume resistivity of 3X 10¹⁰～5×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝4.5、M₁/M₃6.0. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 5

A multilayer tape was produced in the same manner as in example 4, except that the amount of mica blended in the rubber layer was 8.0% by weight and the volume fraction was 3.38%.

The resulting multilayer tape had a thickness of 330 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.33, and a surface resistivity of 3X 10¹⁰～6×10¹⁰Omega/□, volume resistivity of 1X 10¹⁰～2×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝3.6、M₁/M₃4.8. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 6

A multilayer belt was produced in the same manner as in example 1, except that the filler blended in the rubber layer was zirconia (TMZ zirconia, average particle diameter D50 ═ 1.3 μm, manufactured by the first rare-element chemical industry co., ltd.), the amount thereof was 9.6% by weight, and the volume fraction was 1.96%.

The obtained multilayer tape had a thickness of 324 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.40, and a surface resistivity of 6X 10¹¹～8×10¹¹Omega/□, volume resistivity of 9X 10¹⁰～2×10¹¹Ω · cm, surface roughness (Rz) 0.7 μm.

In addition, the mass concentration ratio (M) of zirconium was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝2.7、M₁/M₃3.2. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 7

A multilayer belt was produced in the same manner as in example 1, except that the rubber elastic layer was formed of the following 2 layers having different hardness.

(preparation of first rubber layer)

To a solution prepared by dissolving 22.6g of a blocked polyurethane prepolymer (URE-HYPER RUP1627, manufactured by Dainippon ink Co., Ltd.) in 55.8g of toluene was added 0.35g of aliphatic diamine-based curing agent CLH-5 (manufactured by Dainippon ink Co., Ltd.), and 1.05g of 4, 4-methylenebis (2-methylcyclohexylamine) (manufactured by Dainippon ink Co., Ltd.) as an aliphatic diamine-based curing agent was similarly added and stirred. The solution thus obtained had a solid content of 30 wt%, and was uniformly applied to the inner surface of the surface layer prepared in advance while rotating, and heating was started. The temperature was raised to 150 ℃ at 1 ℃/min, and the drum was rotated and heated at this temperature for 30 minutes to form a first rubber elastic layer of 40 μm on the inner surface of the drum, and the drum was cooled to room temperature.

The elastic layer of the first rubber layer was laminated to a thickness of 10mm in the same manner as in the case of the polyurethane raw material solution to prepare a single rubber elastic layer film, and the type a hardness was measured to find that it was 71 °.

(preparation of second rubber layer)

A118.7-terminated polyurethane prepolymer (URE-HYPERRUP 1627, manufactured by Dainippon ink Co., Ltd.) was dissolved in 153g of toluene to obtain a solution, 9.3g of a curing agent CLH-5 (manufactured by Dainippon ink Co., Ltd.) of an aliphatic diamine was added thereto and stirred, the obtained solution was coated on the inner surface of the first rubber layer, and a second rubber layer was formed into a film having a thickness of 210 μm in the same manner as the first rubber layer.

The elastic layer of the second rubber layer was laminated to a thickness of 10mm in the same manner as the polyurethane raw material solution to prepare a single rubber elastic layer film, and the type a hardness was measured to find that it was 40 °.

A multilayer tape was produced in the same manner as in example 1.

The resulting multilayer tape had a thickness of 322 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.36, and a surface resistivity of 3X 10¹¹～5×10¹¹Omega/□, volume resistivity of 6X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.6 μm.

Comparative example 1

A multilayer tape was produced in the same manner as in example 1, except that no filler was blended in the rubber layer.

The resulting multilayer had a thickness of 328 μm, an outer circumference of 945.0mm, a coefficient of static friction of 0.48, and a surface resistivity of 2X 10¹¹～5×10¹¹Omega/□, volume resistivity of 4X 10¹⁰～7×10¹⁰Ω · cm, surface roughness (Rz) 0.6 μm.

Comparative example 2

A multilayer tape was produced in the same manner as in comparative example 1, except that 5.53g of CLH-5 (manufactured by Dainippon ink Co., Ltd.) and 4.09g of 4, 4-methylenebis (2-methylcyclohexylamine) (manufactured by Dainippon ink Co., Ltd.) were used as the curing agents.

The elastic layer was laminated to a thickness of 10mm in the same manner as the above polyurethane raw material solution to prepare a single rubber elastic layer film, and the hardness of type A was measured to find that it was 55 °.

The resulting multilayer tape had a thickness of 330 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.43, and a surface resistivity of 3X 10¹¹～6×10¹¹Omega/□, volume resistivity of 4X 10¹⁰～8×10¹⁰Ω · cm, surface roughness (Rz) 0.6 μm.

Comparative example 3

A multilayer tape was produced in the same manner as in comparative example 1, except that 2.21g of CLH-5 (manufactured by Dainippon ink Co., Ltd.) and 6.55g of 4, 4-methylenebis (2-methylcyclohexylamine) (manufactured by Dainippon ink Co., Ltd.) were used as the curing agents.

The elastic layer was laminated to a thickness of 10mm in the same manner as the above polyurethane raw material solution to prepare a single rubber elastic layer film, and the hardness of type A was measured to find that it was 71 °.

The resulting multilayer tape had a thickness of 328 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.37, and a surface resistivity of 4X 10¹¹～7×10¹¹Omega/□, volume resistivity of 6X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.5 μm.

Comparative example 4

A multilayer tape was produced in the same manner as in example 1, except that the amount of aluminum borate blended was 0.6% by weight and the volume fraction was 0.24%.

The resulting multilayer tape had a thickness of 329 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.40 and a surface resistivity of 1X 10¹¹～4×10¹¹Ω/□，Volume resistivity of 4X 10¹⁰～8×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝5.7、M₁/M₃5.3. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Comparative example 5

A multilayer tape was produced in the same manner as in example 1, except that the amount of aluminum borate blended was 10.5% by weight and the volume fraction was 4.03%.

The resulting multilayer tape had a thickness of 346 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.30 and a surface resistivity of 5X 10¹¹～9×10¹¹Omega/□, volume resistivity of 8X 10¹⁰～2×10¹¹Ω · cm, surface roughness (Rz) 0.8 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝18.9、M₁/M₃46.6. From this, it was confirmed that the filler concentration in the region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μm was higher than that in the center of the rubber layer.

Comparative example 6

A multilayer belt was produced in the same manner as in example 1, except that the filler blended in the rubber layer was potassium titanate (manufactured by Tismo D red ottoman chemical corporation) in an amount of 2.0% by weight and in a volume fraction of 0.71%.

The resulting multilayer tape had a thickness of 330 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.36, and a surface resistivity of 1X 10¹¹～2×10¹¹Omega/□, volume resistivity of 7X 10¹⁰～1×10¹¹Ω · cm, surface roughness (Rz) 0.8 μm.

In addition, the titanium mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝1.05、M₁/M₃1.05. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μm was substantially the same as the filler concentration in the center of the rubber layer.

Comparative example 7

A multilayer belt was produced in the same manner as in comparative example 6, except that the amount of potassium titanate blended in the rubber layer was 5.0% by weight and the volume fraction was 1.73%.

The resulting multilayer tape had a thickness of 335 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.35 and a surface resistivity of 2X 10¹¹～5×10¹¹Omega/□, volume resistivity of 8X 10¹⁰～1×10¹¹Ω · cm, surface roughness (Rz) 0.9 μm.

In addition, the titanium mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝1.06、M₁/M₃1.12. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μm was substantially the same as the filler concentration in the center of the rubber layer.

Comparative example 8

A multilayer tape was produced in the same manner as in example 1, except that the filler blended in the rubber layer was dry silica (Reolosil (trade name), manufactured by Tokuyama corporation), the amount thereof was 10% by weight, and the volume fraction thereof was 5.43%.

ObtainedThe multilayer tape had a thickness of 359 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.39, and a surface resistivity of 1X 10¹¹～3×10¹¹Omega/□, volume resistivity of 6X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.6 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝1.01、M₁/M₃1.07. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer to the base layer side to a depth of 20 μm was substantially the same as the filler concentration in the center of the rubber layer.

Test example 1

The multilayer tapes obtained in examples 1 to 7 and comparative examples 1 to 8 were evaluated as follows. The results are shown in Table 2.

< Primary transfer efficiency (line missing) >

The primary transfer efficiency (line missing) was determined by the above equation for transfer efficiency by measuring the toner weight on the photoreceptor before and after transfer with an image of only a line image. Line missing was evaluated by the following criteria.

O: higher than 90 percent

△：85～90％

X: less than 85 percent

< Secondary transfer efficiency (matte paper transferability) >

Continuous printing was performed in magenta over the entire surface (image density: magenta 100%) using a Strathmore Writing ruled paper manufactured by Strathmore corporation having an unevenness of about 50 μm, and the adhesion of the toner in the deepest portion (recessed portion) was visually judged. The evaluation criteria are as follows.

Very good: complete the transfer without unevenness

O: slightly pale in color

And (delta): a small amount of white leakage

X: without toner adhesion and without white leakage

< paper passing durability test >

The paper feeding, energization and driving tests were carried out simultaneously under the following conditions, and after 10 ten thousand driving tests, the presence or absence of cracks and peeling in the surface layer was observed with a microscope to confirm the surface roughness and image quality of the tape, and the cracking and peeling in the surface layer were evaluated by the following evaluation criteria.

Driving speed: with an outer peripheral speed of 300 mm/sec

Electrifying: a constant current of 50 μ A was supplied in the thickness direction of the ribbon by a power supply (Trek 610C)

Paper passing: the copy paper is wound around the outer surface of the secondary transfer roller to produce a simulated continuous paper feeding state

Cleaning equipment: cleaning blade made of urethane rubber (rubber hardness A type 80 degree)

(surface layer breaking)

The fracture was evaluated by using a laser microscope VK-9700 manufactured by Keyence.

The tape was observed at 1000 times of 20 times by 50 times by an objective lens x 50 times by an eyepiece before and after the passing, and the line thickness was measured under the following measurement conditions (JIS B0601-2001 standard) using the image of the tape surface obtained by the observation.

And (3) inclination correction: the correction of the face tilt (automatic),

cutoff: the number of the Chinese characters is zero,

measuring length: 0.25 mm.

The surface portions different at 5 were measured in the same band, and the average value of the maximum valley depths Rv was calculated by subtracting the value of Rv before passing durability [ Rv (after passing durability) -Rv (before passing durability) ] from the value of Rv after passing durability.

O: less than 0.3 μm

△：0.3～0.6μm

X: over 0.6 μm

(surface layer peeling)

The evaluation of the peeling was carried out by visually observing the tape after passing through the paper for durability, and the evaluation was carried out according to the following criteria.

O: no peeling was observed over the entire surface of the tape

And (delta): peeling of 1X 1mm square or less was observed

X: it was confirmed that the peeling was 1X 1mm square or more

< IRHD rubber hardness >

The rubber hardness was measured from the surface layer side of the belt according to JIS K6253 using an IRHD microhardness tester (model H12, manufactured by Wallace Co.).

[ Table 1]

[ Table 2]

Example 8

(1) Film formation of substrate layer

47.6g of 4, 4' -diaminodiphenyl ether (ODA) was added to 488g N-methyl-2-pyrrolidone under nitrogen flow, and the mixture was kept at 50 ℃ and stirred to be completely dissolved. To this solution, 70g of 3, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride (BPDA) was slowly added to obtain 605.6g of a polyamic acid solution. The polyamic acid solution had a number average molecular weight of 19000, a viscosity of 40 poise and a solid content of 18.1 wt%.

Then, to 450g of the polyamic acid solution, 21g of an acidic carbon black (pH3.0) and 80g N-methyl-2-pyrrolidone were added, and uniform dispersion of Carbon Black (CB) was carried out by a ball mill. The master batch solution had a solid content concentration of 18.6 wt% and a CB concentration in the solid content of 20.5 wt%.

Then 273g of the solution was collected and poured into a rotary drum, and molded under the following conditions.

Rotating the drum: the inner surface mirror-finished metal drum having an inner diameter of 301.5mm and a width of 540mm was placed on 2 rotating rolls and was arranged so as to rotate together with the rotation of the rolls (see, for example, fig. 2).

Heating temperature: a far infrared heater is disposed on the outer surface of the drum, and the temperature of the inner surface of the drum is controlled to 120 ℃.

First, 273g of the solution was uniformly applied to the inner surface of the drum while the rotary drum was rotated, and heating was started. The temperature was raised to 120 ℃ at 1 ℃ per minute, and the rotation was maintained at this temperature for 60 minutes and heating was carried out.

After the completion of the rotation and heating, the rotary drum was directly detached without cooling, and was allowed to stand in a hot air convection oven to start heating for imidization. The heating also slowly increased the temperature to 320 ℃. Then, the resultant was heated at this temperature for 30 minutes, cooled to room temperature, and peeled off to take out the semiconductive tubular polyimide tape formed on the inner surface of the drum. The tape had a thickness of 79 μm, an outer circumference of 944.3mm, and a surface resistivity of 2X 10¹¹～4×10¹¹Omega/□, volume resistivity of 1X 10⁹～3×10⁹Ω·cm。

(2) Film formation of surface layer

100g of VdF-HFP co-polymerized resin (KYNAR #2821, manufactured by ARKEMA: HFP11 mol%) which was a copolymer of vinylidene fluoride (VdF) and Hexafluoropropylene (HFP) was dissolved in 900g N, N-dimethylacetamide (DMAc) to prepare a solution A having a solid content of 10 wt%.

To 900g of dimethylacetamide was added 100g of organically modified montmorillonite (LucentitesSTN, manufactured by CO-OP Chemical Co., Ltd.), and the mixture was uniformly dispersed by a ball mill to prepare a solution B having a solid content concentration of 10% by weight.

A solution A and a solution B were mixed by a paint shaker so that the ratio of A to B was 99: 1, and a solution having a solid content of 10% by weight and an organic modified montmorillonite content of 1% by weight was obtained. This was diluted with a mixed solvent of DMAc and butyl acetate at a ratio of 1: 2 to prepare a solution (hereinafter, also referred to as a surface layer material) having a solid content of 1.6 wt% and a concentration of the organically modified montmorillonite in the solid content of 1 wt% (corresponding to a blending ratio of montmorillonite to the total weight of the surface layer). 112g of this solution was formed into a film under the following conditions.

Rotating the drum: a metal drum having an inner diameter of 301.0mm, a width of 540mm, and an inner surface ten-point average roughness (Rz) of 0.5 μm was placed on 2 rotating rolls and was arranged so as to rotate together with the rotation of the rolls (see, for example, fig. 2).

The inner surface of the drum was uniformly coated while the rotary drum was rotated, and heating was started. The heating was carried out while raising the temperature to 130 ℃ at 2 ℃/min, and the rotation was maintained at this temperature for 20 minutes, and the drum was cooled to room temperature after the surface layer was formed on the inner surface of the drum. The thickness of the surface layer formed on the inner surface of the drum was measured by an eddy current type thickness meter (manufactured by Kett chemical research Co., Ltd.) and found to be 2 μm.

Further, a surface layer of 10 μm was separately prepared under the same film forming conditions using the above surface layer material. The volume resistance value of the 10 μm surface layer was 4X 10¹²Ω · cm, Young's modulus 610MPa, surface roughness (Rz) of the surface layer was 0.6. mu.m.

(3) Production of elastic layer

To a solution prepared by dissolving 141.3g of a blocked polyurethane prepolymer (URE-HYPER RUP1627, manufactured by makai ink (ltd)) in 188g of toluene was added 7.93g of amorphous particulate barium sulfate (BALIACE B-54, manufactured by sakai chemical industry, having an average particle diameter D50 of 1.2 μm) having an average aspect ratio of 2.3 as a filler, and the mixture was uniformly dispersed by a ball mill. To the dispersion was added 11.07g of aliphatic diamine-based curing agent CLH-5 (manufactured by Dainippon ink Co., Ltd.) and the mixture was stirred.

The solid content concentration of the solution obtained in this way was 46% by weight, and the volume fraction of barium sulfate in the solid content was 1.31% by weight and 5.0% by weight. The dispersion was uniformly applied to the inner surface of the surface layer prepared in advance while rotating, and heating was started. The temperature was raised to 150 ℃ at 1 ℃/min, and the drum was rotated and heated at this temperature for 30 minutes to form a rubber elastic layer on the inner surface of the drum.

The rotational speed of the rotating drum in this heating phase is 7.4 times the centrifugal acceleration of the gravitational acceleration.

In general, the acceleration of gravity (g) is 9.8 (m/s)²)。

The centrifugal acceleration (G) is derived from the following formula (I).

G(m/s²)＝r·ω²＝r·(2·π·n)²(I)

Here, r represents the radius (m) of the cylindrical die, ω represents the angular velocity (rad/s), and n represents the number of revolutions for 1 second (the number of revolutions for 60 seconds is rpm). According to the formula (I), the rotation condition of the cylindrical die can be appropriately set.

The thickness of the resulting rubber elastic layer was 258 μm.

A single layer film of a rubber elastic layer was produced in the same manner as described above except that no filler was added to the polyurethane raw material solution for an elastic layer, and the film was laminated to a thickness of 10mm, and the type a hardness was measured, and found to be 40 °.

(4) Adhesion of the inner face of the rubber elastic layer to the outer face of the polyimide

A primer DY39-067 (manufactured by Dow Corning Toray) was applied to the inside surface of the rubber elastic layer formed by the above-mentioned (3), and after air-drying, a polyimide tape (1) coated with a thin dry lamination adhesive on the outside surface was inserted and laminated. Pressing and bonding the substrate layer from the inner surface of the substrate layer, and heating (80-100 ℃) to finish bonding. The bonded multilayer tape was peeled off from the die, and both ends were cut to obtain a multilayer tape having a width of 360 mm.

The multilayer tape had a thickness of 333 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.39, and a surface resistivity of 1X 10¹¹～3×10¹¹Omega/□, volume resistivity of 4X 10¹⁰～6×10¹⁰Ω · cm, surface roughness (Rz) 0.5 μm.

Further, the mass concentration ratio (M) of barium was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝1.8、M₁/M₃2.1. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 9

A multilayer belt was produced in the same manner as in example 8, except that the filler blended in the rubber layer was amorphous granular zirconia (UEP zirconia, average particle diameter D50 being 0.6 μm, manufactured by first dilute element chemical industry corporation) having an average aspect ratio of 2.1, the amount thereof was 8% by weight, and the volume fraction was 1.63%.

The resulting multilayer tape had a thickness of 340 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.36, and a surface resistivity of 3X 10¹¹～5×10¹¹Omega/□, volume resistivity of 8X 10¹⁰～1×10¹¹Ω · cm, surface roughness (Rz) 0.8 μm.

In addition, the mass concentration ratio (M) of zirconium was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝2.5、M₁/M₃2.8. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 10

A multilayer tape was produced in the same manner as in example 9, except that the zirconia blended in the rubber layer was amorphous granular zirconia having an average aspect ratio of 1.9 (EP zirconia, average particle diameter D50 ═ 1.1 μm, manufactured by the first rare-element chemical industry co., ltd.), the amount thereof was 5% by weight, and the volume fraction was 1.02%.

The resulting multilayer tape had a thickness of 339 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.38, and a surface resistivity of 1X 10¹¹～4×10¹¹Omega/□, volume resistivity of 5X 10¹⁰～8×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

In addition, the mass concentration ratio (M) of zirconium was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝2.8、M₁/M₃3.1. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 11

A multilayer belt was produced in the same manner as in example 10, except that the amount of zirconia blended in the rubber layer was 3% by weight and the volume fraction was 0.62%.

The resulting multilayer tape had a thickness of 337 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.40 and a surface resistivity of 1X 10¹¹～2×10¹¹Omega/□, volume resistivity of 4X 10¹⁰～6×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

In addition, the mass concentration ratio (M) of zirconium was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝3.4、M₁/M₃3.9. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 12

A multilayer tape was produced in the same manner as in example 8, except that the filler blended in the rubber layer was amorphous granular aluminum borate having an average aspect ratio of 1.7 (alumina PF-03, average particle diameter D50 of 2.6 μm, manufactured by seiko chemical industries, ltd.), the amount thereof was 3 wt%, and the volume fraction thereof was 1.17%.

The resulting multilayer tape had a thickness of 338 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.33, and a surface resistivity of 3X 10¹¹～6×10¹¹Omega/□, volume resistivity of 5X 10¹⁰～9×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝1.4、M₁/M₃1.5. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 13

A multilayer tape was produced in the same manner as in example 8, except that the filler blended in the rubber layer was spherical silica (SP30, average particle diameter D50 was 2.6 μm, manufactured by MICRON corporation) having an average aspect ratio of 1.1, in an amount of 5% by weight and a volume fraction of 2.77%.

The resulting multilayer tape had a thickness of 342 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.25, and a surface resistivity of 1X 10¹¹～3×10¹¹Omega/□, volume resistivity 2X 10¹⁰～5×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝4、M₁/M₃4.5. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 14

A multilayer tape was produced in the same manner as in example 8, except that the filler blended in the rubber layer was spherical silica (S-0, average particle diameter D50 being 3.7 μm, manufactured by MICRON corporation) having an average aspect ratio of 1.1, in an amount of 5% by weight and a volume fraction of 2.77%.

The resulting multilayer tape had a thickness of 342 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.27, and a surface resistivity of 1X 10¹¹～3×10¹¹Omega/□, volume resistivity of 2X 10¹⁰～5×10¹⁰Ω · cm, surface roughness (Rz) 0.9 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝2.9、M₁/M₃4.7. Thus, it was confirmed that the interface between the surface layer and the rubber elastic layer was directed to the substrateThe concentration of the filler contained in the region from the layer side to the depth of 20 μm is higher than that in the center of the rubber layer.

Example 15

A multilayer tape was produced in the same manner as in example 8, except that 3% by weight of a filler was blended, and 1.17% by volume fraction of needle-like aluminum borate having an average aspect ratio of 21.6 (Arborex, average particle diameter D50 ═ 20 μm, manufactured by seiko chemical industries, ltd.).

The resulting multilayer tape had a thickness of 331 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.31, and a surface resistivity of 1X 10¹¹～3×10¹¹Omega/□, volume resistivity of 5X 10¹⁰～8×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the aluminum content concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝39.7、M₁/M₃54.6. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 16

A multilayer tape was produced in the same manner as in example 8, except that plate-like mica (SomasifMTE, average particle size D50 is 6.0 μm, manufactured by CO-OPChemical corporation) having an average aspect ratio of 8.0, in which 5% by weight of the filler was blended and 2.17% by volume fraction.

The resulting multilayer tape had a thickness of 341 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.31, and a surface resistivity of 5X 10¹⁰～7×10¹⁰Omega/□, volume resistivity of 3X 10¹⁰～5×10¹⁰Ω · cm, surface roughness (Rz) 0.7 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝4.1、M₁/M₃6.0. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Example 17

A multilayer tape was produced in the same manner as in example 8, except that the filler blended in the rubber layer was spherical silica (S-COX88, average particle size D50 was 8.5 μm, manufactured by MICRON corporation) having an average aspect ratio of 1.1, in an amount of 5 wt%, and in a volume fraction of 2.77%.

The resulting multilayer tape had a thickness of 344 μm, an outer circumference of 945.0mm, a static friction coefficient of 0.31, and a surface resistivity of 2X 10¹¹～3×10¹¹Omega/□, volume resistivity of 3X 10¹⁰～8×10¹⁰Ω · cm, surface roughness (Rz) 1.6 μm.

Further, the silicon mass concentration ratio (M) was measured by cross-sectional observation with an electron microscope (SEM) and by EDX₁/M₂、M₁/M₃) Result is M₁/M₂＝5.9、M₁/M₃6.0. From this, it was confirmed that the concentration of the filler contained in the region extending from the interface between the surface layer and the rubber elastic layer toward the base layer side to a depth of 20 μm was higher than the concentration in the center of the rubber layer.

Test example 2

The multilayer tapes obtained in examples 8 to 17 were evaluated as follows. The results are shown in Table 3.

The paper passing durability test (surface layer breakage), secondary transfer efficiency (matte paper transfer), and IRHD rubber hardness test were performed in the same manner as in test example 1.

< evaluation of halftone image >

An image of halftone (image density: magenta 30%) was printed on the entire surface, and the obtained image was enlarged by 50 times to confirm the presence or absence of noise on the entire surface of the image.

Very good: no noise was found at all

O: only a small amount of noise is found

And (delta): discovery of noise

X: finding a large amount of noise

[ Table 3]

[ Table 4]

Claims (8)

1. An intermediate transfer belt for image formation, characterized in that:

an intermediate transfer belt for an image forming apparatus, comprising at least 3 resin base layers, (b) a rubber or elastomer rubber elastic layer having a thickness of 200 to 400 [ mu ] m, and (c) a resin surface layer having a thickness of 0.5 to 6 [ mu ] m, laminated in this order,

(i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5-4.5N/mm at an indentation depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The surface roughness Rz of the surface layer is 0.25 to 1.5 μm, and/or

(ii) The rubber elastic layer is added with a filler in an amount of 0.4-4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface of the surface layer and the rubber elastic layer to the base layer side to the depth of 20 mu M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

2. The intermediate transfer belt for image formation according to claim 1, characterized in that:

(i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5-4.5N/mm at an indentation depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The surface roughness Rz of the surface layer is 0.25 to 1.5 μm, and,

the surface layer is made of fluorine-based resin, and/or

The surface layer is added with layered clay minerals.

3. An intermediate transfer belt for image formation, characterized in that:

an intermediate transfer belt for an image forming apparatus, comprising at least 3 resin base layers, (b) a rubber or elastomer rubber elastic layer having a thickness of 200 to 400 [ mu ] m, and (c) a resin surface layer having a thickness of 0.5 to 6 [ mu ] m, laminated in this order,

(i) the dynamic ultrafine hardness (ISO14577-1) measured from the surface layer side is 2.5-4.5N/mm at an indentation depth of 2 μm²At a penetration depth of 10 μm, 1.0N/mm²The following; and

(ii) the rubber elastic layer is added with a filler in an amount of 0.4-4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface of the surface layer and the rubber elastic layer to the base layer side to the depth of 20 mu M₁And the slave surfaceThe mass concentration M of the filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the layer and the rubber elastic layer to the base material layer side₃Ratio of (M)₁/M₃) Is 1.3 or more.

4. An intermediate transfer belt for image formation, characterized in that:

an intermediate transfer belt for an image forming apparatus, comprising at least 3 resin base layers, (b) a rubber or elastomer rubber elastic layer having a thickness of 200 to 400 [ mu ] m, and (c) a resin surface layer having a thickness of 0.5 to 6 [ mu ] m, laminated in this order,

(ii) the rubber elastic layer is added with a filler in an amount of 0.4-4.0% by volume fraction, and the mass concentration M of the filler contained in a region from the interface of the surface layer and the rubber elastic layer to the base layer side to the depth of 20 mu M₁And a filler contained in a region having a depth of 120 to 140 [ mu ] M from the interface between the surface layer and the rubber elastic layer toward the base layer₃Ratio of (M)₁/M₃) Is 1.3 or more.

5. The intermediate transfer belt for image formation according to any one of claims 1 to 4, characterized in that: the rubber elastic layer is composed of at least 2 layers with different hardness, and the A-type hardness of the rubber layer on the surface layer side is higher than that of the rubber layer on the base layer side.

6. The intermediate transfer belt for image formation according to any one of claims 1 to 4, characterized in that: the Young's modulus of the surface layer is 300-2000 MPa.

7. The intermediate transfer belt for image formation according to any one of claims 1 to 4, characterized in that: the IRHD hardness (JIS K6253) measured from the surface layer side is 82IRHD or less.

8. A method of manufacturing an intermediate transfer belt for an image forming apparatus according to any one of claims 1 to 4, comprising:

(1) a step of producing a base material layer by centrifugal molding or melt extrusion molding of a resin;

(2) a step of producing a surface layer having a thickness of 0.5 to 6 μm by centrifugally forming a solution obtained by dissolving or swelling a resin in an organic solvent using a cylindrical mold;

(3) forming a 2-layer film by forming a rubber elastic layer containing a filler into a rubber elastic layer having a thickness of 200 to 400 μm by centrifugal molding on the inner surface of the surface layer obtained in the step (2); and

(4) and (3) laminating the outer surface of the base material layer obtained in the step (1) and the inner surface of the 2-layer rubber elastic layer obtained in the step (3) and performing heat treatment.