JP5609506B2 - Intermediate transfer member and image forming apparatus using the intermediate transfer member - Google Patents

Description

  The present invention relates to an intermediate transfer member and an image forming apparatus using the intermediate transfer member.

  Conventionally, in an electrophotographic apparatus, a latent image formed on an image carrier (also referred to as a photoconductor) is developed with toner, and the obtained toner image is temporarily held on an intermediate transfer member. An intermediate transfer system that transfers the toner image on a recording medium such as paper is known. In particular, in a recent full-color electrophotographic apparatus, an intermediate transfer belt in which developed images of four colors of yellow, magenta, cyan, and black are once color-superposed on a belt-shaped intermediate transfer member and then transferred to a recording medium in a lump. The method is used.

  The intermediate transfer belt method has been conventionally used in a system using four color developing devices for one photoconductor. However, this system has a drawback that the printing speed is low. On the other hand, as the high-speed printing, a four-tandem tandem system is used in which the photoreceptors are arranged for four colors and each color is continuously transferred to paper. However, in this method, there are fluctuations due to the environment of the paper, and it is very difficult to match the positions where the color images are overlaid, which causes a so-called color misregistration image. Therefore, in recent years, it has become mainstream to adopt an intermediate transfer method in a quadruple tandem image forming apparatus.

  Under such circumstances, the required characteristics (for example, high-speed transfer, position accuracy, etc.) are also stricter than those of conventional intermediate transfer belts, and it is necessary to satisfy these required characteristics. It is coming. In particular, regarding the positional accuracy, it is required to suppress fluctuations due to deformation such as elongation of the intermediate transfer belt itself due to continuous use. Further, since the intermediate transfer belt is laid out over a wide area of the image forming apparatus, it is required to have a high elastic modulus, and since a high voltage is applied for transfer, the flame retardant is required. It is required to be sex. In order to meet such demands, as the material of the intermediate transfer belt, polyimide resin, polyamideimide resin, and the like, which are high elastic modulus and high heat resistance resin, are mainly used.

  However, since the intermediate transfer belt made of polyimide resin has high strength and high surface hardness, when the intermediate transfer belt is used, a high pressure is applied to the toner layer when the toner image is transferred, and the toner does not move. There is a case where a so-called hollow image is generated in which a part of the image is aggregated and a part of the image is not transferred. In addition, contact followability with a contact member at a transfer portion such as a photoconductor or paper is inferior, so that a partial contact failure portion (gap) may occur in the transfer portion, and transfer unevenness may occur.

  In recent years, full-color electrophotography has been used to form images on various types of paper. In addition to ordinary smooth paper, recycled paper and embossed paper can be used not only from smooth paper, but also from slippery and highly smooth paper. The usage rate of paper with rough surfaces such as paper, Japanese paper, and kraft paper is increasing. Such followability to papers having different surface properties is important. If the followability is poor, there is a problem that unevenness of the unevenness of the paper and unevenness of color tone occur. In order to solve this problem, various intermediate transfer belts in which a relatively flexible layer (elastic layer) is laminated on a base layer have been proposed.

  However, when the elastic layer is a surface layer, the transfer pressure is reduced, and the followability to the unevenness of the paper is improved. There is a problem that efficiency is lowered and the former effect cannot be utilized. There is also a problem that it is inferior in wear resistance or scratch resistance.

In order to solve this problem, there is a method of newly providing a protective layer on the elastic layer. However, when a material having a sufficiently high transfer performance is coated, the elasticity of the elastic layer cannot be followed, and cracking and peeling will occur. There is a problem that occurs. On the other hand, in order to solve the above problem, proposals have been made to improve transferability by attaching fine particles to the surface.
For example, it has been proposed to coat the surface of the intermediate transfer member with beads having a diameter of 3 μm or less (see Patent Document 1). However, with this proposal, detachment of beads occurs, and this is not sufficient to satisfy the durability of the surface layer required for recent electrophotographic apparatuses.
In addition, it has been proposed to form a surface layer with a material having affinity for the hydrophobized fine particles (see Patent Documents 2 and 3). In this proposal, particles having a very small particle size are preferably used. However, the particle layer is thick, and due to the aggregation of the particles, non-uniform portions are formed in the particle layer, and the transfer performance also varies. Therefore, it satisfies the high level of image quality required for recent electrophotographic apparatuses. Not what you get.
In addition, a configuration has been proposed in which the surface layer of the intermediate transfer body is made fine by embedding the fine particles in a resin to some extent so that the durability of the surface layer is also realized (see Patent Documents 4 and 5). However, even in this proposal, the presence of particles becomes non-uniform, and the high image quality required for the recent electrophotographic apparatus cannot be satisfied.
Further, in all the above proposals, silica particles are preferably used. However, since silica particles have a strong cohesive force, a uniform particle layer cannot be formed as described above. In addition, inorganic particles such as silica easily damage and wear the surface of the organic photoconductor due to contact with the organic photoconductor preferably used as a latent image carrier for image formation. This causes a problem of reducing durability.

In view of this, it has been proposed to increase durability by including a resin such as polyphenylsulfone, polysulfone, polyethersulfone, polyester, polyacetal, polyarylate, polyamide and polycarbonate in the surface layer and silicone particles or fluorine particles. (See Patent Document 6). However, in this proposal, since particles such as silicone particles and fluorine particles are very difficult to disperse in the resin, there is a problem that the particles tend to aggregate and transfer unevenness easily occurs. The following is also insufficient. A method of blending a rubber material with these surface layers has also been proposed, but there is also a problem that the transfer performance is further deteriorated when the rubber material is blended.
In addition, it has been proposed to include a filler in the surface layer of the intermediate transfer member (see Patent Document 7). However, in this proposal, since the coating layer uses a flexible material whose micro hardness is in the range of 10 ° to 75 °, the surface layer has wear resistance, scratch resistance, durability, although cracking does not occur. There is a problem that it is inferior.
In addition, it has been proposed that the amount of solvent in forming the surface layer by applying fine particles by a wet method is 30% or more (see Patent Document 8). However, this proposal has a problem that, depending on the type of fine particles or other components, agglomeration occurs at the time of coating, resulting in uneven portions in the surface layer and uneven transfer performance.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention is flexible, has excellent toner releasability, can achieve a high transfer rate regardless of the type or surface shape of the recording medium, can be maintained for a long time, and has a durable surface layer. An object of the present invention is to provide an intermediate transfer member that is excellent and can maintain a stable and high-quality image over a long period without causing damage to the organic photoreceptor, and an image forming apparatus using the intermediate transfer member.

Means for solving the problems are as follows. That is,
<1> An intermediate transfer body onto which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred,
The intermediate transfer member has a laminated structure including a base layer, an elastic layer, and a surface layer sequentially from the inside,
The intermediate transfer member is characterized in that the surface layer contains spherical particles and one of a silicone-modified resin and a fluorine-modified resin.
<2> The intermediate transfer member according to <1>, wherein the spherical particles are any of silicone particles and fluorine particles.
<3> The intermediate transfer member according to any one of <1> to <2>, wherein an average particle diameter of the spherical particles is 5.0 μm or less.
<4> The intermediate transfer member according to any one of <1> to <3>, wherein an average thickness of the surface layer is 10 μm or less.
<5> The intermediate transfer member according to any one of <1> to <4>, wherein the elastic layer is any one of a thermosetting elastomer and a rubber material.
<6> The intermediate transfer member according to any one of <1> to <5>, wherein the base layer is any one of a polyimide resin and a polyamideimide resin.
<7> An image carrier on which a latent image is formed and capable of carrying a toner image;
Developing means for developing the latent image formed on the image carrier with toner;
An intermediate transfer body on which a toner image developed by the developing means is primarily transferred;
Transfer means for secondary transfer of the toner image carried on the intermediate transfer member to a recording medium,
An image forming apparatus, wherein the intermediate transfer member is the intermediate transfer member according to any one of <1> to <6>.
<8> The image forming apparatus is a full-color image forming apparatus,
The image forming apparatus according to <7>, wherein a plurality of latent image carriers having developing units for each color are arranged in series.

  According to the present invention, the above-mentioned problems can be solved, the object can be achieved, the toner is flexible, has excellent toner releasability, and has a high transfer rate regardless of the type or surface shape of the recording medium. An intermediate transfer body capable of maintaining a high-quality image stable over a long period of time, having a surface layer with excellent durability and no damage to the organic photoreceptor, An image forming apparatus using an intermediate transfer member can be provided.

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the intermediate transfer member of the present invention. FIG. 2 is a schematic diagram showing an example of the shape of the spherical particles of the present invention. FIG. 3 is a schematic diagram of a main part showing an example of a rotary type image forming apparatus equipped with the intermediate transfer member of the present invention as a belt member. FIG. 4 is a schematic diagram of a main part showing an example of a quadruple tandem type image forming apparatus equipped with the intermediate transfer member of the present invention as a belt member.

(Intermediate transfer member)
The intermediate transfer member of the present invention is an intermediate transfer belt type electrophotographic apparatus [so-called a plurality of color toner development images sequentially formed on an image carrier (for example, a photosensitive drum) are sequentially superimposed on the intermediate transfer belt. In this case, the intermediate transfer belt is suitably equipped with an apparatus that performs primary transfer and collectively transfers the primary transfer image onto a recording medium.
FIG. 1 shows an example of a layer structure of an intermediate transfer belt that is preferably used in the present invention. As the layer structure, a flexible elastic layer 2 is laminated on a rigid base layer 1 that can be relatively flexible, and a coating resin in which spherical particles are dispersed is laminated on the outermost surface as a surface layer 3. Yes.

<Base layer>
There is no restriction | limiting in particular as a constituent material of the said base layer, According to the objective, it can select suitably, For example, it contains the filler or additive (what is called an electrical resistance regulator) which adjusts electrical resistance in it. Resin. In addition, the resin may further contain additives such as a dispersion aid, a reinforcing agent, a lubricant, a heat conductive agent, and an antioxidant as necessary.

-Resin-
The resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, a fluorine-based resin such as polyvinylidene fluoride (PVDF) or ethylene / tetrafluoroethylene copolymer (ETFE), a polyimide resin, or a polyamide. An imide resin or the like is preferable in terms of flame retardancy. Among these, a polyimide resin or a polyamideimide resin is particularly preferable in terms of mechanical strength (high elasticity) and heat resistance. Details of the polyimide resin and the polyamideimide resin will be described later.

-Electric resistance regulator-
There is no restriction | limiting in particular as said electrical resistance modifier, According to the objective, it can select suitably, For example, a metal oxide, carbon black, an ionic conductive agent, a conductive polymer material etc. are mentioned. Examples of the metal oxide include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. Moreover, in order to improve dispersibility, the metal oxide may be subjected to surface treatment in advance. Examples of the carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black. Examples of the ionic conductive agent include tetraalkylammonium salts, trialkylbenzylammonium salts, alkylsulfonates, alkylbenzenesulfonates, alkyl sulfates, glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acids. Examples include alcohol esters, alkyl betaines, and lithium perchlorates. These may be used individually by 1 type and may use 2 or more types together.

As the electric resistance value of the base layer, an electric resistance adjusting agent is added so that the surface resistance is 1 × 10 ⁸ to 1 × 10 ¹⁴ Ω / □ and the volume resistance is 1 × 10 ⁷ to 1 × 10 ¹³ Ω · cm. It is preferable to do. However, if the amount of the electrical resistance modifier added is too large, the base layer becomes brittle and easily cracked, so a material that can be achieved with an amount that does not hinder the mechanical strength is selected. In other words, when the base layer of the intermediate transfer belt is used, an electric liquid is prepared using a coating liquid in which the blending of the resin component (for example, polyimide resin precursor, polyamideimide resin precursor) and the electrical resistance adjuster is appropriately adjusted. It is preferable to manufacture and use a base layer having a balance between characteristics (surface resistance and volume resistance) and mechanical strength.

  As content of the said electrical resistance modifier, in the case of carbon black, it is 10 mass%-25 mass% of the total solid of a coating liquid, and 15 mass%-20 mass% are preferable. Moreover, in the case of a metal oxide, it is 1 mass%-50 mass% of the total solid of a coating liquid, and 10 mass%-30 mass% are preferable. When the content is less than the lower limit value of the content range of the respective electric resistance adjusting agents, it becomes difficult to obtain uniformity of the electric resistance value, and the fluctuation of the electric resistance value with respect to an arbitrary potential increases. Further, when the content exceeds the upper limit value of the respective ranges, the mechanical strength of the intermediate transfer belt is lowered.

  The coating liquid used for the formation of the base layer includes additives such as a dispersion aid, a reinforcing agent, a lubricant, a heat conductive agent, and an antioxidant, as necessary, in addition to the resin and electrical resistance modifier selected from the above. It is prepared by mixing. An endless belt is obtained by applying the coating liquid to a support (molding die) as described later and then performing a treatment such as heating.

The average thickness of the base layer is preferably 30 μm to 150 μm, and more preferably 40 μm to 80 μm. If the average thickness is less than 30 μm, the belt may be easily torn, and if it exceeds 150 μm, the belt may be easily broken.
The average thickness can be measured by a contact type (pointer type) or eddy current type film thickness meter, for example, an electronic make meter (manufactured by Anritsu Corporation).

  The polyimide resin (hereinafter sometimes abbreviated as “polyimide”) and the polyamideimide resin (hereinafter sometimes abbreviated as “polyamideimide”) that are preferably used as the material of the base layer are specifically described below. explain.

--- Polyimide--
There is no restriction | limiting in particular as a polyimide used for this invention, Although it can select suitably according to the objective, For example, an aromatic polyimide is preferable. The aromatic polyimide is obtained via a polyamic acid (polyimide precursor) by a reaction between a generally known aromatic polycarboxylic acid anhydride (or a derivative thereof) and an aromatic diamine. The polyimide, particularly the aromatic polyimide, is insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, first, a polyimide precursor (polyamic acid or polyamic acid) that is soluble in an organic solvent is synthesized by a reaction between an aromatic polycarboxylic acid anhydride and an aromatic diamine, and various processes are performed at the polyimide precursor stage. Then, the polyimide precursor is subjected to a dehydration reaction by heating or a chemical method to be cyclized (imidized) to obtain a polyimide. As an example, the outline of the reaction for obtaining an aromatic polyimide is shown in the following formula (1).

(In the formula, Ar ¹ represents a tetravalent aromatic residue containing at least one carbon 6-membered ring, and Ar ² represents a divalent aromatic residue containing at least one carbon 6-membered ring. Moreover, the terminal of the molecule | numerator in a formula is a hydrogen atom.)

  The aromatic polycarboxylic acid anhydride is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, pyromellitic acid Dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′- Biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4 -Dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis ( , 3-Dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3 3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6 -Naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracene Examples thereof include tetracarboxylic dianhydride and 1,2,7,8-phenanthrenetetracarboxylic dianhydride. These may be used individually by 1 type and may use 2 or more types together.

  Next, the aromatic diamine to be reacted with the aromatic polyvalent carboxylic acid anhydride is not particularly limited and may be appropriately selected depending on the intended purpose. For example, m-phenylenediamine, o-phenylenediamine, p- Phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis (3-aminophenyl) sulfide, (3 -Aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) ) Sulfone, (3-aminophenyl) (4-aminophenyl) Nyl) sulfone, bis (4-aminophenyl) sulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′- Diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3- Aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4 -(4-Aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenoxy) phenyl] propa 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, 2,2-bis [3- (3-aminophenoxy) ) Phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Fluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4- Aminophenoxy) benzene, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, biphenyl Sus [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-amino Phenoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [ 4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [ 4- (3-Aminophenoxy) benzoyl] benzene, 4,4′-bis [3- (4-aminophenoxy) Nzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4, 4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4 -(4-aminophenoxy) phenoxy] -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, in order to effectively express the physical properties of the present invention, it is preferable to use 4,4'-diaminodiphenyl ether as at least one of the components.

  A polyimide precursor (polyamic acid) can be obtained by carrying out a polymerization reaction in an organic polar solvent using substantially equimolar amounts of the aromatic polycarboxylic anhydride component and the diamine component. Below, the manufacturing method of a polyamic acid is demonstrated concretely.

  The organic polar solvent used for the polymerization reaction of the polyamic acid is not particularly limited as long as it dissolves the polyamic acid, and can be appropriately selected according to the purpose. For example, dimethyl sulfoxide, diethyl sulfoxide Sulfoxide solvents such as N, N-dimethylformamide, formamide solvents such as N, N-diethylformamide, acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide, N-methyl-2- Pyrrolidone solvents such as pyrrolidone and N-vinyl-2-pyrrolidone, phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol and catechol, ethers such as tetrahydrofuran, dioxane and dioxolane Solvent, methanol, ethanol , Alcohol solvents butanol, cellosolves or hexamethylphosphoramide, such as butyl cellosolve, etc. γ- butyrolactone. Among these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

  As an example in the case of producing the polyimide precursor, first, one or a plurality of diamines are dissolved or dispersed in a slurry state in an inert gas atmosphere such as argon or nitrogen. When at least one kind of the aromatic polyvalent carboxylic acid anhydride or derivative thereof is added to this solution (either in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state), it opens with heat generation. Cyclopolyaddition reaction occurs, the viscosity of the solution increases rapidly, and a high molecular weight polyamic acid solution is obtained. As reaction temperature in this case, it is -20 degreeC-100 degreeC normally, and 60 degrees C or less is preferable. The reaction time is about 30 minutes to 12 hours.

  The above is an example. Contrary to the addition procedure in the reaction, the aromatic polycarboxylic acid anhydride or derivative thereof is first dissolved or diffused in an organic solvent, and the diamine may be added to this solution. Good. The diamine may be added in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state. That is, the mixing order of the acid dianhydride component and the diamine component is not limited. Further, the aromatic tetracarboxylic dianhydride and the aromatic diamine may be simultaneously added to the organic polar solvent for reaction.

  As described above, the polyamic acid is uniformly dispersed in the organic polar solvent by polymerizing approximately equimolar amounts of the aromatic polycarboxylic acid anhydride or derivative thereof and the aromatic diamine component in the organic polar solvent. A polyimide precursor solution is obtained in a dissolved state.

  As the polyimide precursor solution (polyamic acid solution) in the present invention, the one synthesized as described above can be used, but the so-called polyamic acid composition is simply dissolved in an organic solvent. What is marketed as a polyimide varnish can also be used. Examples of the commercially available products include Trenys (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries), Rika Coat (manufactured by Nippon Nippon Chemical Co., Ltd.), Optmer (manufactured by JSR Corporation), SE812 (manufactured by Nissan Chemical Industries, Ltd.), CRC8000. (Made by Sumitomo Bakelite Co., Ltd.).

  The coating solution used for forming the base layer is prepared by mixing or dispersing a filler in the polyamic acid solution as necessary. The coating liquid is applied to a support (molding mold) as described later, and then subjected to a treatment such as heating, whereby conversion (imidation) from polyamic acid, which is a polyimide precursor, to polyimide is performed.

The polyamic acid can be imidized by a heating method (1) or a chemical method (2). The heating method (1) is a method of converting polyamic acid to polyimide by, for example, heat treatment at 200 ° C. to 350 ° C., and is a simple and practical method for obtaining polyimide (polyimide resin). On the other hand, the chemical method (2) is a method in which a polyamic acid is reacted with a dehydrating cyclization reagent (for example, a mixture of a carboxylic acid anhydride and a tertiary amine, etc.) and then heated to completely imidize, Compared with the heating method of (1), since it is a complicated and expensive method, the method of (1) is usually used frequently.
In order to exhibit durability (mechanical strength) and heat resistance, which are intrinsic properties of polyimide, it is preferable to complete imidization by heating to a temperature equal to or higher than the glass transition temperature of the corresponding polyimide.

The progress of the imidization (degree of imidization) can be evaluated by a usual method for measuring the imidization rate.
As a method for measuring the imidization rate, for example, nuclear magnetic resonance spectroscopy (calculated from an integral ratio of 1H attributed to an amide group in the vicinity of 9 ppm to 11 ppm and 1H attributed to an aromatic ring in the vicinity of 6 ppm to 9 ppm ( NMR methods), Fourier transform infrared spectroscopy (FT-IR method), methods for quantifying moisture accompanying imide ring closure, and carboxylic acid neutralization titration methods, among others, Fourier transform infrared spectroscopy. The method (FT-IR method) is the most common method.

In the Fourier transform infrared spectroscopy (FT-IR method), the imidization rate is defined as, for example, the following formula (a). That is, assuming that (A) is the number of moles of imide groups at the firing stage (imidization stage), and (B) is the number of moles of imide groups when 100% imidized (theoretical), a).
Imidation ratio (%) = [(A) / (B)] × 100 (a)

  The number of moles of the imide group in this definition can be determined from the absorbance ratio of the characteristic absorption of the imide group measured by the FT-IR method. For example, as a typical characteristic absorption, the imidization ratio can be evaluated using the following absorbance ratio.

(1) Absorbance ratio between 725 cm ⁻¹ (immobilization vibration band of imide ring C═O group) which is one of characteristic absorptions of imide and benzene ring characteristic absorption of 1,015 cm ⁻¹ (2) Characteristics of imide Absorbance ratio between 1,380 cm ⁻¹ (inflection band of imide ring C—N group) which is one of absorption and characteristic absorption of 1,500 cm ^{−1 of} benzene ring (3) One of characteristic absorption of imide Absorbance ratio between 1,720 cm ⁻¹ (an oscillating band of imide ring C═O group) and 1,500 cm ⁻¹ characteristic absorption of benzene ring (4) 1, which is one of characteristic absorption of imide Absorbance ratio between 720 cm ⁻¹ and amide group characteristic absorption 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and C—N stretching vibration) and 3,000 cm ^{−1 to} 3,300 cm The multiple absorption band derived from the amide group over ^-1 disappears If it is confirmed, the reliability of imidization completion is further increased.

--Polyamideimide--
The polyamide-imide is a resin having a rigid imide group and a amide group imparting flexibility in the molecular skeleton, and the polyamide-imide used in the present invention has a generally known structure. be able to.
In general, as a method for synthesizing a polyamideimide resin, an acid chloride method (a): a derivative halide of a trivalent carboxylic acid having an acid anhydride group, most typically a chloride compound of the derivative and a diamine are used as solvents. There is known a known method for producing it by reacting in the method (for example, see Japanese Examined Patent Publication No. 42-15637). Further, as another method, an isocyanate method (b): a known method for producing a trivalent derivative containing an acid anhydride group and a carboxylic acid and an aromatic isocyanate in a solvent (for example, JP-B-44) No. 19274) are known, and any of them can be used. Each manufacturing method will be described below.

(A) Acid Chloride Method The trivalent carboxylic acid derivative halide compound having an acid anhydride group is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the following formulas (2) and ( The compound shown in 3) can be used.

(Wherein X represents a halogen element)

(Wherein X represents a halogen element and Y represents any of —CH ₂ —, —CO—, —SO ₂ — and —O—)

  In each of the above formulas, the halogen element is not particularly limited and may be appropriately selected according to the purpose. However, a chloride is preferable, and examples of the derivative include terephthalic acid, isophthalic acid, 4, 4 ′ biphenyldicarboxylic acid, 4, 4 'Biphenyl ether dicarboxylic acid, 4, 4' biphenyl sulfone dicarboxylic acid, 4, 4 'benzophenone dicarboxylic acid, pyromellitic acid, trimellitic acid, 3, 3', 4, 4 'benzophenone tetracarboxylic acid, 3, 3,' 4,4'biphenylsulfonetetracarboxylic acid, 3,3'4,4'biphenyltetracarboxylic acid, adipic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, stilbene dicarboxylic acid, 1,4 cyclohexanedicarboxylic acid Acid chlora of polyvalent carboxylic acids such as 1,2 cyclohexanedicarboxylic acid De, and the like. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as said diamine, According to the objective, it can select suitably, For example, aromatic diamine, aliphatic diamine, alicyclic diamine etc. are mentioned. Among these, aromatic diamines are preferable.
The aromatic diamine is not particularly limited and may be appropriately selected depending on the intended purpose. For example, m-phenylenediamine, p-phenylenediamine, oxydianiline, methylenediamine, hexafluoroisopropylidenediamine, diamino- m-xylylene, diamino-p-xylylene, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis- (4-aminophenyl) ) Propane, 2,2′-bis- (4-aminophenyl) hexafluoropropane, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfone, 3,3 '-Diaminodiphenyl ether, 3,4-diaminobiphenyl, 4,4'- Diaminobenzophenone, 3,4-diaminodiphenyl ether, isopropylidenedianiline, 3,3′-diaminobenzophenone, o-tolidine, 2,4-tolylenediamine, 1,3-bis- (3-aminophenoxy) benzene, 1 , 4-bis- (4-aminophenoxy) benzene, 1,3-bis- (4-aminophenoxy) benzene, 2,2-bis- [4- (4-aminophenoxy) phenyl] propane, bis- [4 -(4-aminophenoxy) phenyl] sulfone, bis- [4- (3-aminophenoxy) phenyl] sulfone, 4,4'-bis- (4-aminophenoxy) biphenyl, 2,2'-bis- [4 -(4-aminophenoxy) phenyl] hexafluoropropane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyls Examples include luffide. These may be used individually by 1 type and may use 2 or more types together.

  Further, as the diamine, a siloxane compound having amino groups at both ends, for example, 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis ( 3-aminopropyl) polydimethylsiloxane, 1,3-bis (3-aminophenoxymethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3-aminophenoxymethyl) polydimethylsiloxane 1,3, -bis (2- (3-aminophenoxy) ethyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (2- (3-aminophenoxy) ethyl) polydimethyl Siloxane, 1,3-bis (3- (3-aminophenoxy) propyl) -1,1,3,3-tetramethyldisiloxane, α, ω-bis (3- (3-aminophenoxy) Silicone-modified polyamideimide can be obtained by using () propyl) polydimethylsiloxane.

  In order to obtain the polyamideimide (polyamideimide resin) in the present invention by the acid chloride method, as in the case of the production of the polyimide resin, the above-described trivalent carboxylic acid derivative halide and diamine having an acid anhydride group Is dissolved in an organic polar solvent and then reacted at a low temperature (0 ° C. to 30 ° C.) to obtain a polyamideimide precursor (polyamide-amic acid).

  As in the case of the polyimide, the organic polar solvent is not particularly limited as long as it dissolves polyamic acid, and can be appropriately selected according to the purpose. For example, a formamide solvent (for example, dimethyl sulfoxide) Sulfoxide solvents such as diethyl sulfoxide, N, N-dimethylformamide, N, N-diethylformamide, etc.), acetamide solvents (for example, N, N-dimethylacetamide, N, N-diethylacetamide, etc.), pyrrolidone solvents (Eg, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, etc.), phenolic solvents (eg, phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol, etc.), Ether solvents (eg, tetrahydrofuran, dioxane) Dioxolane), alcohol solvents (e.g., methanol, ethanol, butanol, etc.), cellosolve-based solvents (e.g., butyl cellosolve, etc.), hexamethylphosphoramide, γ- butyrolactone. Among these, N, N-dimethylacetamide and N-methyl-2-pyrrolidone are preferable. These may be used individually by 1 type and may use 2 or more types together.

After the polyamide / polyamic acid solution obtained as described above is applied to a support (molding mold), conversion (imidation) from polyamic acid to polyimide is performed by treatment such as heating.
Examples of the imidization method include a method of dehydrating and ring-closing by heat treatment, and a method of chemically ring-closing using a dehydrating and ring-closing catalyst. When dehydrating and ring-closing by heat treatment, the reaction temperature is 150 ° C to 400 ° C, preferably 180 ° C to 350 ° C, and the heat treatment time is 30 seconds to 10 hours, preferably 5 minutes to 5 hours. . When a dehydration ring closure catalyst is used, the reaction temperature is 0 ° C. to 180 ° C., preferably 10 ° C. to 80 ° C., and the reaction time is tens of minutes to several days, 2 hours to 12 hours is preferred. Examples of the dehydration ring closure catalyst include acid anhydrides such as acetic acid, propionic acid, butyric acid, and benzoic acid.

(B) Isocyanate method As the derivative of the trivalent carboxylic acid having an acid anhydride group used in the case of the isocyanate method, for example, compounds represented by the formulas (4) and (5) can be used.

(In the formula, R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group)

(In the formula, R represents any of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a phenyl group, and Y represents —CH ₂ —, —CO—, —SO ₂ — or —O—).

  Any of the derivatives represented by the above general formula can be used, but the most typical one is trimellitic anhydride. In addition, these trivalent carboxylic acid derivatives having an acid anhydride group may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as aromatic polyisocyanate used in the case of the said isocyanate method, According to the objective, it can select suitably, For example, 4,4'- diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4, 4'-diphenyl ether diisocyanate, 4,4 '-[2,2-bis (4-phenoxyphenyl) propane] diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4 '-Diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2, , 2'-Diethyl bifu Nyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, naphthalene-2 , 6-diisocyanate. These may be used individually by 1 type and may use 2 or more types together. Further, as necessary, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m- At least one of aliphatic such as xylylene diisocyanate and lysine diisocyanate, alicyclic isocyanate and trifunctional or higher polyisocyanate can also be used.

  A solution containing a polyamidoimide precursor obtained by dissolving a derivative of a trivalent carboxylic acid having each acid anhydride group and an aromatic polyisocyanate in an organic polar solvent is applied to a support, and then heat-treated. Thus, the conversion from the polyamideimide precursor to the polyamideimide is performed. Upon conversion to a polyamideimide by this method, a polyamideimide is generated (by generating carbon dioxide gas) without passing through a polyamic acid. The following formula (6) shows an example of polyamide imidization when trimellitic anhydride and aromatic isocyanate are used.

(In the formula, Ar represents an aromatic group)

  The polyimide and polyamideimide are usually used alone, but those selected in consideration of compatibility can also be used in combination. Moreover, the copolymer which has a polyimide repeating unit and a polyamideimide repeating unit may be sufficient.

  Next, the elastic layer laminated | stacked on the said base layer is demonstrated.

<Elastic layer>
There is no restriction | limiting in particular as a material which comprises the said elastic layer, According to the objective, it can select suitably, For example, materials, such as general purpose resin, an elastomer, rubber | gum, can be used, The effect of this invention An elastomer material or a rubber material is preferable in that it has sufficient flexibility (elasticity) to develop the above.
The elastomer material is not particularly limited and may be appropriately selected according to the purpose. Examples of the thermoplastic elastomer include polyester-based, polyamide-based, polyether-based, polyurethane-based, polyolefin-based, polystyrene-based, and polyacrylic. System, polydiene system, silicone-modified polycarbonate system, and fluorine copolymer system. In addition, examples of thermosetting include polyurethane, silicone-modified epoxy, and silicone-modified acrylic. These may be used individually by 1 type and may use 2 or more types together.
The silicone modification rate of the elastomer is preferably 30% by mass to 80% by mass and more preferably 50% by mass to 60% by mass in terms of flexibility. When the modification rate is less than 30% by mass, there is a problem that the flexibility is insufficient and the followability to paper is insufficient.
The rubber material is not particularly limited and can be appropriately selected according to the purpose. For example, isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, chloroprene rubber, Acrylic rubber, chlorosulfonated polyethylene, fluorine rubber, urethane rubber, hydrin rubber and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.
The material for the elastic layer is appropriately selected from the above-mentioned various elastomers and rubbers. In the present invention, a thermosetting material is preferable from the viewpoint of forming a resin layer on the surface of this material. The thermosetting material is excellent in adhesiveness with the resin layer due to the effect of the functional group contributing to the curing reaction, and can be reliably fixed. Vulcanized rubber is also preferable from the same viewpoint.

  It is preferable that the elastic layer has a rubber hardness of 80 ° or less and a flexible material having a rubber hardness of 60 ° or less. The rubber hardness can be measured by using a commercially available rubber hardness meter, for example, a micro rubber hardness meter MD-1 (manufactured by Kobunshi Keiki Co., Ltd.).

  The coating liquid for forming the elastic layer includes a resistance adjusting agent (electrical resistance adjusting agent) for adjusting electrical characteristics, a flame retardant for obtaining flame retardancy, and, if necessary, the selected material. Thus, materials such as antioxidants, reinforcing agents, fillers, vulcanization accelerators, and the like are appropriately added and adjusted.

As the electrical resistance adjusting agent, the various materials described above can be applied. However, since carbon black and metal oxides impair the flexibility of the elastic layer, it is preferable to suppress the amount used. It is also preferable to use molecules. These may be used in combination.
The electric resistance value of the elastic layer is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ in terms of surface resistance and 1 × 10 ⁷ to 1 × 10 ¹³ Ω · cm in terms of volume resistance.

  The average thickness of the elastic layer is preferably 200 μm to 2 mm. If the average thickness is less than 200 μm, the followability to the surface properties of the transfer medium and the effect of reducing the transfer pressure may be reduced. If the average thickness is more than 2 mm, the elastic layer will be heavy and bend easily. The running performance becomes unstable, and cracks are likely to occur due to bending at the roller curvature portion for stretching the belt. In addition, the said average thickness can be measured by observing the cross section of the obtained belt with a scanning microscope (SEM).

Next, the surface layer (uppermost layer) laminated on the elastic layer will be described.

<Surface layer>
The surface layer of the intermediate transfer member of the present invention contains at least spherical particles and one of a silicone-modified resin and a fluorine-modified resin, and further, a resistance adjuster for adjusting electrical characteristics as required, a flame retardant It contains an additive such as a flame retardant for obtaining good properties and a leveling agent for improving wettability.

-Resin-
As the resin constituting the surface layer, either a silicone-modified resin or a fluorine-modified resin having good releasability is used. The silicone-modified resin is not particularly limited and can be appropriately selected depending on the purpose. For example, silicone-modified polyimide, silicone-modified polyamideimide, silicone-modified polyamide, silicone-modified polycarbonate, silicone-modified acrylic, silicone-modified epoxy, Examples include silicone-modified urethane, silicone-modified polyester, silicone-modified olefin, silicone-modified vinyl, and silicone-modified phenoxy. The fluorine-modified resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), and polychlorotrifluoroethylene. (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), ethylene chlorotrifluoroethylene (ECTFE), polyvinyl fluoride ether (PFVE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), Examples thereof include tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). These may be used individually by 1 type and may use 2 or more types together. However, the same resin is used for the resin used in the surface layer and the resin for performing the surface treatment of spherical particles described later.

Here, the modification means having a structure in which a large number of substituents are introduced into fluorine atoms or silicon atoms in the resin (structure having substituents at side chains and / or terminals).
There is no restriction | limiting in particular as said substituent, According to the objective, it can select suitably, For example, a polyether group, an epoxy group, amines, a carboxyl group, an aralkyl group etc. are mentioned.
The modification ratio (modification ratio) is preferably 20% or more, and more preferably 50% or more, from the viewpoint of toner releasability.

  Subsequently, the spherical particles used in the present invention will be described.

-Spherical particles-
The spherical particles constituting the surface layer are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include resins such as acrylic resins, melamine resins, polyamide resins, polyester resins, silicone resins, and fluorine resins. Spherical particles containing as the main component. Further, the surface of spherical particles made of these resin materials may be subjected to surface treatment with a different material. Further, the spherical particles made of the resin material referred to here include a rubber material. A structure in which the surface of spherical particles made of the rubber material is coated with a hard resin is also applicable. The spherical particles may be hollow or porous. Among these spherical particles, silicone particles or fluorine particles are particularly preferable because they have lubricity and can impart releasability to toner and abrasion resistance. These spherical particles may be used alone or in combination of two or more.

Here, the spherical shape does not have to be a true spherical shape, but includes a case of a substantially spherical shape. The shape of the spherical particles can be expressed by the following shape rule.
FIG. 2 is a schematic diagram showing an example of the shape of the spherical particles of the present invention. In FIG. 2, when a substantially spherical particle is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the particle has a ratio of a major axis to a minor axis. (R2 / r1) (see FIG. 2B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 2C) is 0.7 to 1. It is preferably in the range of 0. If the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the particles are likely to aggregate between particles because they are separated from the true spherical shape.
In addition, r1, r2, r3 can be measured by the following method, for example. That is, the spherical particles are uniformly dispersed and adhered on a smooth measurement surface, and the 100 spherical particles are magnified 1000 times by a color laser microscope (VK-8500, manufactured by Keyence Corporation) to obtain the 100 spherical particles. The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values.

  The spherical particles have a volume average particle size of preferably 0.1 μm to 10.0 μm, more preferably 0.3 μm to 3.0 μm.

The surface treatment of the spherical particles is not particularly limited as long as the surface of the spherical particles can be coated with the silicone-modified resin or fluorine-modified resin as a treating agent, and can be appropriately selected according to the purpose.
Examples of the surface treatment include a dry method such as plasma CVD, and a wet method performed by milling in a solvent, but wet treatment is preferable because the treatment is simple. Below, the case where it carries out by wet is demonstrated. The resin and spherical particles in a solvent are pulverized or dispersed using beads, ultrasonic waves, etc., and the surface of the spherical particles is treated with silicone resin or fluororesin to suppress aggregation between the spherical particles. At the same time, the spherical particles are atomized. Subsequently, while adjusting the dispersion time, a predetermined particle size is obtained. The size of the spherical particles in the solution can be confirmed with a commercially available particle size analyzer, for example, NanotracUPA-150EX (manufactured by Nikkiso Co., Ltd.). The wet dispersion apparatus used for the surface treatment is not particularly limited as long as spherical particles can be pulverized, and can be appropriately selected according to the purpose. Examples thereof include a ball mill, a bead mill, and a paint shaker.

  The surface treatment to the spherical particles is performed by changing the mass blending ratio of the spherical particles and the resin. As for the said compounding ratio, it is preferable that spherical particles are 0.5-5.0 with respect to resin 1.0 (solid content). If the blending ratio is less than 0.5, since there are few spherical particles, the surface layer after drying is likely to be worn out and easily broken. When the blending ratio exceeds 5.0, not only are there spherical particles that are not surface-treated due to too many spherical particles, but also an abnormal image is generated due to an increase in the roughness of the belt surface, or spherical particles. Due to the remaining charging potential due to, image disturbance due to accumulation of this potential may occur during continuous image output. On the other hand, if the blending ratio is 0.5 to 5.0, the surface layer is difficult to break, and even if a minute crack occurs, the crack does not expand further due to the presence effect of the spherical particles. Problems such as toner entering the belt and poor belt cleaning do not occur.

  The content of the spherical particles is preferably lower from the viewpoint of wet coating, and specifically, 1% by mass to 20% by mass is preferable, and 5% by mass to 10% by mass is more preferable.

  The solvent for applying the resin and the spherical particles to the surface layer is preferably a low boiling point solvent because it can be quickly vaporized after being applied to the elastic layer. For example, methyl ethyl ketone (MEK), tetrahydrofuran (THF), ethyl acetate, acetone, butyl acetate, cyclohexanone, 2-heptanone (MAK), propylene glycol monomethyl ether acetate (PGMEA) and the like. When a solvent having a boiling point exceeding 200 ° C. is used, the elastic layer may be deteriorated during the surface layer drying.

The coating liquid for forming the surface layer includes spherical particles selected from the above, one of a silicone-modified resin and a fluorine-modified resin, a solvent, and a resistance adjustment for adjusting electrical characteristics as necessary. It adjusts by adding suitably additives, such as an agent, a flame retardant for obtaining a flame retardance, and a leveling agent for improving wettability.
The range in which the coating liquid is applied onto the elastic layer can be appropriately selected according to the purpose, and may be applied to the entire elastic layer or a part thereof. .

  The average thickness of the surface layer is preferably 10 μm or less, and more preferably 5 μm or less. When the average thickness exceeds 10 μm, the flexibility of the elastic layer is impaired, and the followability and deformability of the intermediate transfer belt to the paper may be deteriorated.

  Next, an example of a method for producing an intermediate transfer member having the laminated structure of the present invention will be described.

First, a method for producing a base layer using a coating solution containing the polyimide resin precursor or the polyamideimide resin precursor will be described.
While slowly rotating a cylindrical mold, for example, a cylindrical metal mold, a coating liquid containing at least a resin component (for example, a coating liquid containing a polyimide resin precursor or a polyamideimide resin precursor) is used as a nozzle or Application and casting (formation of a coating film) is performed uniformly on the entire outer surface of the cylinder by a liquid supply device such as a dispenser. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and the rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80 to 150 degreeC, heating up gradually, rotating a metal mold | die. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting coating film is formed, the mold is transferred to a heating furnace (baking furnace) capable of high-temperature treatment, and the temperature is raised stepwise, and finally high-temperature heat treatment (about 250 ° C. to 450 ° C. ( Calcination) and sufficiently imidization of the polyimide resin precursor or polyamide imidization of the polyamideimide resin precursor. Thereafter, by sufficiently cooling, an endless belt (base layer) made of polyimide or polyamideimide is obtained. Subsequently, an elastic layer is laminated on the obtained base layer.

  The elastic layer can be formed on the base layer by injection molding, extrusion molding, or the like. Here, a method of applying and forming on the base layer using a thermosetting liquid elastomer material will be described. The coating liquid containing at least a liquid thermosetting elastomer material is made uniform over the entire outer surface of the cylinder by a liquid supply device such as a nozzle or a dispenser while slowly rotating the cylindrical metal mold like the base layer. Coating or casting (forming a coating film). Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached at a desired time, the rotation speed is maintained at a constant speed and the rotation is continued. Then, when sufficiently leveled, it is cured by heating at a predetermined temperature for a predetermined time to form an elastic layer. After sufficiently cooling, a resin layer in which spherical particles are dispersed is subsequently coated to form a surface layer.

  The surface layer is uniformly applied and cast on the entire outer surface of the cylinder with a liquid supply device such as a spray, nozzle, dispenser, etc. while slowly rotating the cylindrical metal mold in the same manner as the method for producing the elastic layer ( A coating film is formed). After that, when sufficiently leveled, the resin layer is formed by curing by heating at a predetermined temperature and a predetermined time while rotating. After sufficiently cooling, the base layer is detached from the mold to obtain a desired intermediate transfer belt.

(Image forming device)
The intermediate transfer belt manufactured by the above-described method performs, for example, a primary transfer by sequentially superimposing a plurality of color toner developed images sequentially formed on the image carrier on the intermediate transfer belt, and the primary transfer image is covered. It can be suitably used as an intermediate transfer belt of an electrophotographic apparatus of a so-called intermediate transfer type that performs secondary transfer collectively to a recording medium, and can form an electrophotographic image forming apparatus that forms a high-quality image. Hereinafter, it will be described in detail with reference to the schematic diagram of the relevant part. The schematic diagram is an example, and the present invention is not limited to this.

  FIG. 3 is a schematic diagram of a main part for explaining an image forming apparatus equipped with an intermediate transfer member obtained by the manufacturing method according to the present invention as a belt member. The intermediate transfer unit 500 including the belt member shown in FIG. 3 includes an intermediate transfer belt 501 that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt 501, a secondary transfer bias roller 605 that is a secondary transfer charge applying unit of the secondary transfer unit 600, a belt cleaning blade 504 that is an intermediate transfer member cleaning unit, and a lubricant for a lubricant application unit. A lubricant application brush 505 or the like that is an application member is disposed so as to face each other.

  In addition, position detection marks (not shown) are provided on the outer peripheral surface or inner peripheral surface of the intermediate transfer belt 501. However, on the outer peripheral surface side of the intermediate transfer belt 501, it is necessary to devise a position detection mark that avoids the passing area of the belt cleaning blade 504, which may be difficult to arrange. A position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt 501. An optical sensor 514 serving as a mark detection sensor is provided at a position between the primary transfer bias roller 507 and the belt driving roller 508 where the intermediate transfer belt 501 is bridged.

  The intermediate transfer belt 501 includes a primary transfer bias roller 507, a belt driving roller 508, a belt tension roller 509, a secondary transfer counter roller 510, a cleaning counter roller 511, and a feedback current detection roller 512, which are primary transfer charge applying units. It is stretched around. Each roller is formed of a conductive material, and each roller other than the primary transfer bias roller 507 is grounded. The primary transfer bias roller 507 is applied with a transfer bias controlled to a predetermined current or voltage according to the number of superimposed toner images by a primary transfer power source 801 controlled at a constant current or voltage. ing.

  The intermediate transfer belt 501 is driven in the direction of the arrow by a belt drive roller 508 that is driven to rotate in the direction of the arrow by a drive motor (not shown). The intermediate transfer belt 501 as a belt member is usually a semiconductor or an insulator and has a single layer or a multilayer structure. However, in the present invention, a seamless belt is preferably used, and this improves durability. Excellent image formation can be realized. Further, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to overlap toner images formed on the photosensitive drum 200.

  A secondary transfer bias roller 605 serving as a secondary transfer unit is attached to and separated from a belt outer peripheral surface of the intermediate transfer belt 501 in a portion stretched around the secondary transfer counter roller 510 by a contact / separation mechanism, which will be described later. It is configured to be able to contact and separate. The secondary transfer bias roller 605 is disposed so as to sandwich the transfer paper P, which is a recording medium, between the portion of the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and a constant current. A transfer bias having a predetermined current is applied by a secondary transfer power source 802 to be controlled.

  The registration roller 610 feeds the transfer sheet P, which is a transfer material, between the secondary transfer bias roller 605 and the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 at a predetermined timing. The secondary transfer bias roller 605 is in contact with a cleaning blade 608 as a cleaning unit. The cleaning blade 608 is for removing the adhering matter adhering to the surface of the secondary transfer bias roller 605 for cleaning.

  In the color copying machine having such a configuration, when an image forming cycle is started, the photosensitive drum 200 is rotated in a counterclockwise direction indicated by an arrow by a drive motor (not shown), and Bk ( Black) toner image formation, C (cyan) toner image formation, M (magenta) toner image formation, and Y (yellow) toner image formation are performed. The intermediate transfer belt 501 is rotated clockwise by the belt driving roller 508 as indicated by an arrow. As the intermediate transfer belt 501 rotates, the primary transfer of the Bk toner image, the C toner image, the M toner image, and the Y toner image is performed by the transfer bias by the voltage applied to the primary transfer bias roller 507. Finally, the respective toner images are formed on the intermediate transfer belt 501 in the order of Bk, C, M, and Y.

  For example, the Bk toner image formation is performed as follows. In FIG. 3, a charging charger 203 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with a negative charge by corona discharge. The timing is determined based on the belt mark detection signal, and raster exposure with laser light is performed based on the Bk color image signal by a writing optical unit (not shown). When this raster image is exposed, the charge proportional to the exposure light amount disappears in the exposed portion of the surface of the photosensitive drum 200 that is initially uniformly charged, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing device 231K comes into contact with this Bk electrostatic latent image, the toner does not adhere to the remaining portion of the photosensitive drum 200, and the charge is not charged. The toner is attracted to the nonexposed portion, that is, the exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

  The Bk toner image formed on the photosensitive drum 200 in this manner is primarily transferred onto the belt outer peripheral surface of the intermediate transfer belt 501 that is rotating at a constant speed while being in contact with the photosensitive drum 200. Some untransferred residual toner remaining on the surface of the photoreceptor drum 200 after the primary transfer is cleaned by the photoreceptor cleaning device 201 in preparation for reuse of the photoreceptor drum 200. On the photosensitive drum 200 side, the process proceeds to the C image forming process after the Bk image forming process, and reading of C image data by a color scanner starts at a predetermined timing. By writing laser light with the C image data, the photosensitive drum A C electrostatic latent image is formed on the surface of 200.

  Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the C electrostatic latent image arrives, the revolver developing unit 230 is rotated, and the C developing machine 231C develops. The C electrostatic latent image is developed with C toner. Thereafter, the development of the C electrostatic latent image area is continued. When the rear end of the C electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the case of the previous Bk developing machine 231K. The M developing machine 231M is moved to the developing position. This is also completed before the leading edge of the next Y electrostatic latent image reaches the developing position. Note that the M and Y image forming steps are the same as the Bk and C steps described above because the operations of reading color image data, forming an electrostatic latent image, and developing are the same as those described above.

  The Bk, C, M, and Y toner images sequentially formed on the photosensitive drum 200 in this manner are sequentially aligned on the same surface on the intermediate transfer belt 501 and primarily transferred. As a result, a toner image having a maximum of four colors superimposed on the intermediate transfer belt 501 is formed. On the other hand, at the time when the image forming operation is started, the transfer paper P is fed from a paper feed unit such as a transfer paper cassette or a manual feed tray, and is waiting at the nip of the registration roller 610. When the leading edge of the toner image on the intermediate transfer belt 501 reaches the secondary transfer portion where the nip is formed by the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and the secondary transfer bias roller 605. Then, the registration roller 610 is driven so that the leading edge of the transfer paper P coincides with the leading edge of the toner image, and the transfer paper P is conveyed along the transfer paper guide plate 601, and the transfer paper P and the toner image are transferred. Resist alignment is performed.

  In this way, when the transfer paper P passes through the secondary transfer portion, the four-color superimposed toner image on the intermediate transfer belt 501 is transferred by the transfer bias applied by the secondary transfer power source 802 to the secondary transfer bias roller 605. Are collectively transferred (secondary transfer) onto the transfer paper P. After the transfer paper P is conveyed along the transfer paper guide plate 601 and passed through a portion facing the transfer paper neutralization charger 606 composed of a static elimination needle disposed on the downstream side of the secondary transfer portion, the transfer paper P is discharged. Then, it is sent toward the fixing device 270 by the belt conveying device 210 which is a belt component (see FIG. 4). Then, after the toner image is melted and fixed at the nip portions of the fixing rollers 271 and 272 of the fixing device 270, the transfer paper P is sent out of the apparatus main body by a discharge roller (not shown), and is stacked face up on a copy tray (not shown). Is done. Note that the fixing device 270 may be configured to include a belt component if necessary.

  On the other hand, the surface of the photosensitive drum 200 after the belt transfer is cleaned by the photosensitive member cleaning device 201 and is uniformly discharged by the discharging lamp 202. Further, residual toner remaining on the outer peripheral surface of the intermediate transfer belt 501 after the toner image is secondarily transferred to the transfer paper P is cleaned by the belt cleaning blade 504. The belt cleaning blade 504 is configured to be brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by a cleaning member separating and contacting mechanism (not shown).

  On the upstream side of the belt cleaning blade 504 in the moving direction of the intermediate transfer belt 501, a toner seal member 502 is provided that contacts and separates from the outer peripheral surface of the intermediate transfer belt 501. The toner seal member 502 receives the falling toner that has fallen from the belt cleaning blade 504 during cleaning of the residual toner, and prevents the falling toner from being scattered on the transfer path of the transfer paper P. The toner seal member 502 is brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 together with the belt cleaning blade 504 by the cleaning member separating and contacting mechanism.

  The lubricant 506 scraped by the lubricant application brush 505 is applied to the outer peripheral surface of the intermediate transfer belt 501 from which the residual toner has been removed in this way. The lubricant 506 is made of, for example, a solid body such as zinc stearate, and is disposed so as to come into contact with the lubricant application brush 505. Further, residual charges remaining on the outer peripheral surface of the intermediate transfer belt 501 are removed by a neutralizing bias applied by a belt neutralizing brush (not shown) that is in contact with the outer peripheral surface of the intermediate transfer belt 501. Here, the lubricant application brush 505 and the belt neutralizing brush are brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by respective contact and separation mechanisms (not shown). .

  Here, at the time of repeat copy, the operation of the color scanner and the image formation on the photosensitive drum 200 are performed at a predetermined timing following the first color (Y) image formation process of the first sheet and the first color of the second sheet. The process proceeds to the image forming process (Bk). Further, the intermediate transfer belt 501 has a second Bk toner in the area cleaned by the belt cleaning blade 504 on the outer peripheral surface of the belt following the batch transfer process of the first four-color superimposed toner image to the transfer paper. The image is first transferred. After that, the operation is the same as the first sheet. The above is a copy mode for obtaining a four-color full-color copy. In the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. In the case of the single color copy mode, only the predetermined color developing machine of the revolver developing unit 230 is set in the developing operation state until the predetermined number of sheets is completed, and the belt cleaning blade 504 is kept in contact with the intermediate transfer belt 501. The copy operation is performed in the state.

  In the above-described embodiment, the copying machine including only one photosensitive drum 1 has been described. However, the present invention includes a plurality of photosensitive drums as shown in a configuration example in a schematic diagram of a main part in FIG. The present invention can also be applied to an image forming apparatus arranged side by side along one intermediate transfer belt formed of a seamless belt. FIG. 4 shows a configuration of a four-drum digital color printer including four photosensitive drums 21BK, 21Y, 21M, and 21C for forming toner images of four different colors (black, yellow, magenta, and cyan). An example is shown.

  In FIG. 4, the printer body 10 includes an image writing unit 12, an image forming unit 13, and a paper feeding unit 14 for performing color image formation by an electrophotographic method. Based on the image signal, the image processing unit converts the image into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation and transmits them to the image writing unit 12. To do. The image writing unit 12 is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group. Image writing corresponding to each color signal is performed on image carriers (photoconductors) 21BK, 21M, 21Y, and 21C that have a writing optical path and are provided for each color of the image forming unit 13.

  The image forming unit 13 includes photoconductors 21BK, 21M, 21Y, and 21C that are image carriers for black (BK), magenta (M), yellow (Y), and cyan (C). . As each photoconductor for each color, an OPC photoconductor is usually used. Around the photoreceptors 21BK, 21M, 21Y, and 21C, there are a charging device, an exposure unit for laser light from the writing unit 12, and developing devices 20BK, 20M, 20Y for black, magenta, yellow, and cyan, respectively. 20C, primary transfer bias rollers 23BK, 23M, 23Y, and 23C as primary transfer means, a cleaning device (not shown), and a photosensitive member static elimination device (not shown) are arranged. The developing devices 20BK, 20M, 20Y, and 20C use a two-component magnetic brush developing system. The intermediate transfer belt 22, which is a belt component, is interposed between the photosensitive members 21BK, 21M, 21Y, and 21C and the primary transfer bias rollers 23BK, 23M, 23Y, and 23C, and is formed on the photosensitive members. The toner images of each color are sequentially superimposed and transferred.

  On the other hand, the transfer paper P is fed from the paper feed unit 14 and then carried by the transfer conveyance belt 50, which is a belt component, via the registration roller 16. When the intermediate transfer belt 22 and the transfer conveyance belt 50 come into contact, the toner image transferred onto the intermediate transfer belt 22 is subjected to secondary transfer (collective transfer) by a secondary transfer bias roller 60 as a secondary transfer unit. ) As a result, a color image is formed on the transfer paper P. The transfer paper P on which the color image is formed is conveyed to the fixing device 15 by the transfer conveying belt 50, and after the image transferred by the fixing device 15 is fixed, it is discharged out of the printer main body.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt 22 is removed from the intermediate transfer belt 22 by the belt cleaning member 25. A lubricant application device 27 is disposed on the downstream side of the belt cleaning member 25. The lubricant application device 27 includes a solid lubricant and a conductive brush that rubs the intermediate transfer belt 22 to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt 22 and applies a solid lubricant to the intermediate transfer belt 22. The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt 22, preventing the occurrence of filming, and improving the durability.

  EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Those are also within the scope of the present invention. The size of the spherical particles in the surface layer was calculated by observing and measuring a cross section at an arbitrary point of the intermediate transfer belt with a scanning electron microscope (SEM) and calculating an average value.

Example 1
A base layer coating solution was prepared by the procedure shown below, and a base layer of an intermediate transfer belt was produced using this coating solution.
<Preparation of base layer coating solution A>
First, carbon black (Special Black4, Evonik Degussa) dispersed in N-methyl-2-pyrrolidone with a bead mill in advance in a polyimide varnish (U-varnish A, Ube Industries, Ltd.) containing a polyimide resin precursor as a main component. The base layer coating solution A was prepared by preparing a dispersion liquid (manufactured by Kogyo Co., Ltd.) such that the carbon black content was 17% by mass of the polyamic acid solid content, and stirring and mixing well.

<Preparation of base layer>
Next, a metal cylinder having an outer diameter of 340 mm and a length of 300 mm roughened by blasting is used as a mold, and this cylinder mold is rotated at 50 rpm (times / minute) while the base layer coating liquid is used. Was applied by a dispenser so as to be uniformly cast on the outer surface of the cylinder. When the predetermined amount was completely poured and the coating film was evenly spread, the number of revolutions was increased to 100 rpm, introduced into a hot air circulating dryer, gradually heated to 110 ° C. and heated for 60 minutes. Further, the temperature is raised and heated at 200 ° C. for 20 minutes, the rotation is stopped, the cooling is slowly performed, the cylindrical shape on which the coating film is formed is taken out, and this is introduced into a heating furnace (baking furnace) capable of high-temperature treatment. In particular, the temperature was raised to 320 ° C. and heat-treated (baked) for 60 minutes, and then sufficiently cooled. Thereby, an endless belt (base layer) made of polyimide was obtained. The average thickness of the obtained base layer was 60 μm. The thickness was measured with an electronic micrometer KG3001A (manufactured by Anritsu Corporation).

Subsequently, an elastic layer was formed on the base layer using an elastic layer coating solution having the following constitution.
<Preparation of elastic layer coating liquid A>
First, the following constituent materials were mixed and sufficiently kneaded using a biaxial kneader to prepare a master batch.
-Carbon masterbatch material for elastic layer-
・ Silicone-modified epoxy resin (ALBIFEX 348, silicon content 60% by mass
, Manufactured by Nanoresins) 20 parts by mass Carbon black (R400R, manufactured by Cabot Japan Co., Ltd.) 100 parts by mass Using the carbon master batch A, the following constituent materials were mixed to obtain a coating liquid A for elastic layer.
−Coating fluid composition material for elastic layer−
-Carbon masterbatch A 10 parts by mass-Silicone-modified epoxy resin (ALBIFLEX 348, silicon content 60% by mass)
77 parts by mass of methyltetrahydrophthalic anhydride (HN-2000, manufactured by Hitachi Chemical Co., Ltd.)
13 parts by mass

<Production of elastic layer on base layer>
On the polyimide base layer prepared previously, the coating liquid for the resin layer was cast and applied to the outer surface uniformly while rotating the mold using a dispenser in the same manner as the base layer. The coating amount was set to a liquid amount condition such that the final elastic layer had an average thickness of 300 μm. Thereafter, the mold was rotated as it was, and then charged into a hot air circulating dryer, heated to 120 ° C. at a heating rate of 4 ° C./min, and heated for 30 minutes. Then, it heated up to 220 degreeC with the temperature increase rate of 4 degree-C / min, and heat-processed for 60 minutes. The rubber layer thus obtained had a rubber hardness of 47 ° and an average thickness of 300 μm. The rubber hardness was measured with a micro rubber hardness meter MD-1 (manufactured by Kobunshi Keiki Co., Ltd.), and the thickness was measured by observing the cross section of the obtained belt with a scanning electron microscope (SEM).

<Preparation of surface layer coating liquid A>
First, the following constituent materials were mixed and dispersed using a zirconia bead having a diameter of 1 mm for 3 hours using a bead mill disperser to prepare a surface layer coating solution A.
Silicone particles (Tospearl 120, volume average particle size 2.0 μm, manufactured by Momentive Performance Materials) 6 parts by mass Silicone-modified polyimide (SMP-2003, solid content 30%, manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by mass・ Propylene glycol monomethyl ether acetate (manufactured by Sankyo Chemical Co., Ltd.)
74 parts by mass

<Preparation of Intermediate Transfer Belt A>
The surface layer coating liquid A was uniformly applied to the elastic layer produced above by spray coating while rotating the mold. The coating amount was such that the final average thickness of the surface layer was 2.0 μm. Thereafter, the mold was rotated as it was, and was then placed in a hot air circulating dryer and heated at 80 ° C. for 30 minutes. Then, it heated up to 160 degreeC at 4 degree-C / min, and heat-processed for 60 minutes. After stopping the heating, it was gradually cooled to room temperature. After sufficiently cooling, it was removed from the mold to obtain an intermediate transfer belt A. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 1.9 μm, and the volume average particle size of the spherical particles in the surface layer was 0.8 μm.

(Example 2)
The base layer and the elastic layer were produced in the same procedure as in Example 1. About the coating liquid for surface layers, the coating liquid A for surface layers of the said Example 1 was changed into each structural material shown below.
<Preparation of surface layer coating solution B>
Silicone particles (Tospearl 120, volume average particle size 2.0 μm, manufactured by Momentive Performance Materials) 5 parts by mass Tetrafluoroethylene fluororesin (Dinion THV-220, manufactured by Sumitomo 3M Limited) 4 parts by mass Methyl ethyl ketone (manufactured by Sankyo Chemical Co., Ltd.) 91 parts by mass The above constituent materials were mixed and dispersed using a zirconia bead having a diameter of 1 mm for 3 hours using a bead mill disperser to obtain surface layer coating solution B.

<Preparation of intermediate transfer belt B>
The surface layer coating solution B was uniformly applied on the elastic layer produced above by spray coating while rotating the mold. The coating amount was such that the final average thickness of the surface layer was 2.0 μm. Thereafter, the mold was rotated as it was, and was then placed in a hot air circulating dryer and heated at 150 ° C. for 30 minutes. After sufficiently cooling, it was removed from the mold to obtain an intermediate transfer belt B. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 2.1 μm, and the volume average particle diameter of the spherical particles in the surface layer was 0.9 μm.

(Example 3)
The base layer and the elastic layer were prepared in the same procedure as in Example 1. For the surface layer coating solution, the surface layer coating solution A of Example 1 was changed to the following constituent materials.
<Preparation of surface layer coating solution C>
PTFE particles (Fluon L173J, volume average particle size 0.2 μm, manufactured by Asahi Glass Co., Ltd.) 3 parts by mass Silicone modified polyimide (SMP-2003, solid content 30%, manufactured by Shin-Etsu Chemical Co., Ltd.)
8.3 parts by mass Propylene glycol monomethyl ether acetate (manufactured by Sankyo Chemical Co., Ltd.)
88.7 parts by mass The above constituent materials were mixed and dispersed using a zirconia bead having a diameter of 1 mm for 1 hour with a bead mill disperser to obtain a surface layer coating solution C. Thereafter, an intermediate transfer belt C was obtained in the same manner as in Example 1. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 2.4 μm, and the volume average particle diameter of the spherical particles in the surface layer was 0.1 μm.

Example 4
An intermediate transfer belt D was prepared in the same manner as in Example 1 except that the silicone particles (Tospearl 120) in Example 1 were replaced with Tospearl 2000B (volume average particle size 6.0 μm, Momentive Performance Materials). Obtained. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 6.8 μm, and the volume average particle diameter of the spherical particles in the surface layer was 5.2 μm.

(Example 5)
An intermediate transfer belt E was obtained in the same manner as in Example 1 except that the average thickness of the surface layer of Example 1 was changed from 1.9 μm to 11.7 μm. When the cross section of the belt was observed with a scanning electron microscope, the volume average particle diameter of the spherical particles in the surface layer was 2.0 μm.

(Example 6)
An intermediate transfer belt F was obtained in the same manner as in Example 1 except that the silicone particles in Example 1 were replaced with melamine silica particles (Opto beads 3500M, volume average particle size 3.5 μm, Nissan Chemical Co., Ltd.). When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 3.2 μm, and the volume average particle diameter of the spherical particles in the surface layer was 1.1 μm.

(Example 7)
An intermediate transfer belt G was obtained in the same manner as in Example 1 except that the silicone particles in Example 1 were replaced with acrylic particles (Techpolymer XX15FM, volume average particle size 0.1 μm, Sekisui Plastics Co., Ltd.). It was. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 4.3 μm, and the volume average particle size of the spherical particles in the surface layer was 0.08 μm.

(Example 8)
In the said Example 1, the preparation of the coating liquid for base layers, and the preparation methods of a base layer were changed as follows.
<Preparation of base layer coating solution B>
First, carbon black (MA77) dispersed in N-methyl-2-pyrrolidone with a bead mill in advance in a polyamideimide varnish (Vilomax HR-16NN, manufactured by Toyobo Co., Ltd.) containing a polyamideimide resin precursor as a main component. , Manufactured by Mitsubishi Chemical Co., Ltd.) was prepared such that the carbon black content was 22% by mass of the polyamic acid solid content, and the mixture was well stirred and mixed to prepare a base layer coating solution B.

<Preparation of base layer>
Next, a metal cylinder having an outer diameter of 340 mm and a length of 300 mm roughened by blasting is used as a mold, and this cylinder mold is rotated at 50 rpm (times / minute) while the base layer coating liquid is used. Was applied by a dispenser so as to be uniformly cast on the outer surface of the cylinder. When the predetermined amount was completely poured and the coating film was evenly spread, the number of revolutions was increased to 100 rpm, introduced into a hot air circulating dryer, gradually heated to 110 ° C. and heated for 60 minutes. Subsequently, the cylindrical mold on which the coating film was formed was taken out, introduced into a heating furnace (baking furnace) capable of high temperature processing, heated to 250 ° C. stepwise and subjected to heat treatment (baking) for 60 minutes, Cooled well. As a result, an endless belt made of polyamideimide was obtained. The average thickness of the obtained base layer was 60 μm. Thereafter, an intermediate transfer belt H was obtained in the same manner as in Example 1.

Example 9
In Example 1, the method for forming the elastic layer was changed as follows.
First, the following materials were mixed and kneaded with a kneader to prepare a rubber composition.
-Acrylic rubber (Nipol AR12, manufactured by Nippon Zeon Co., Ltd.) 100 parts by mass-Stearic acid (bead stearic acid Tsubaki, manufactured by NOF Corporation) 1 part by mass-Red phosphorus (Nova Excel 140F, manufactured by Phosphorus Chemical Industries, Ltd.) 10 parts by mass Aluminum hydroxide (Hijilite H42M, Showa Denko KK) 60 parts by mass Crosslinking agent [Diak No. 1 (hexamethylenediamine carbamate), manufactured by DuPont Dow Elastomer Japan Co., Ltd.] 0.6 parts by mass Crosslinking accelerator [VULCOFAC ACT 55 (70% 1,8-diazabicyclo (5,4,0) undecene-7 and dibasic Salt with acid, 30% amorphous silica), Safari
produced by alcan] 0.6 parts by mass Conductive agent [AP-1 (quaternary phosphonium salt), produced by Guangei Chemical Co., Ltd.] 0.3 parts by mass Next, the rubber composition thus obtained was used as an organic solvent. A rubber solution having a solid content of 35% by mass was prepared by dissolving in (MIBK: methyl isobutyl ketone). While rotating the cylindrical support on which the prepared polyimide base layer was formed, the prepared rubber solution was moved to the support axis method while continuously discharging rubber paint from the nozzle onto the polyimide base layer. It was applied to. The amount of application was such that the final average thickness was 300 μm. Thereafter, the cylindrical support coated with the rubber paint is put into a hot air circulating dryer while rotating as it is, heated to 90 ° C. at a heating rate of 4 ° C./min and heated for 30 minutes, and then the heating rate The temperature was raised to 170 ° C. at 4 ° C./min and heat-treated for 60 minutes. Thereafter, an intermediate transfer belt I was obtained in the same manner as in Example 1.

(Comparative Example 1)
An intermediate transfer belt J was obtained in the same manner as in Example 1 except that the surface layer coating liquid A of Example 1 did not contain spherical particles. When the cross section of the belt was observed with a scanning electron microscope, the average thickness of the surface layer was 1.8 μm.

(Comparative Example 2)
An intermediate transfer belt K was obtained in the same manner as in Example 1 except that the surface layer coating solution A of Example 1 did not contain silicone-modified polyimide (SMP-2003). When the surface of the belt was observed with a scanning electron microscope, it was found that countless spherical particles were scattered, but the adhesion of the spherical particles was uneven and the elastic layer could be seen through the gaps between the particles. there were.

(Comparative Example 3)
The base layer and the elastic layer were prepared in the same procedure as in Example 1. About the coating liquid for surface layers, the coating liquid A for surface layers of the said Example 1 was changed into each structural material shown below.
<Preparation of surface layer coating solution D>
Silicone particles (Tospearl 120, volume average particle size 2.0 μm, manufactured by Momentive Performance Materials) 3 parts by mass Polycarbonate resin (PCX5, manufactured by Teijin Chemicals Limited) 3 parts by mass Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc.) ) 60 parts by mass ・ Cyclohexanone (manufactured by Kanto Chemical Co., Inc.) 34 parts by mass The above constituent materials are mixed and dispersed using a zirconia bead of φ1 mm for 1 hour with a bead mill disperser to obtain a surface layer coating solution D It was. Thereafter, an intermediate transfer belt L was obtained in the same manner as in Example 1. When the cross section of this belt was observed with a scanning electron microscope, the average thickness of the surface layer was 3.7 μm, and the volume average particle size of the spherical particles in the surface layer was 1.8 μm.

The intermediate transfer belts A to L of Examples 1 to 9 and Comparative Examples 1 to 3 were mounted on the electrophotographic apparatus of FIG. 3, and the following various evaluations were performed.
<(1) Measurement of transfer rate (%)>
As the transfer paper, use a paper with surface irregularities (Rezac 66 215Kg paper), and perform an operation to output a blue solid image (Test Chart No. 5-1 published by the Imaging Society of Japan) Then, the amount of image toner on the intermediate transfer belt before transfer to paper and the amount of toner remaining on the intermediate transfer belt after transfer to paper were measured, and the transfer rate (%) was calculated. The results are shown in Table 2. The transfer rate (%) is expressed by the following formula (b).
Transfer rate (%) = [toner amount on intermediate transfer belt after transfer (g) / toner amount on intermediate transfer belt before transfer (g)] × 100 (b)
The toner amount was measured by measuring a change in mass before and after transfer of the intermediate transfer belt.
<(2) Measurement of transfer rate (%) at the time of continuous image output of 10,000 sheets>
After outputting 10,000 images of the test chart continuously, the test chart was stopped, and the transfer rate (%) was measured in the same manner as (1) above. The results are shown in Table 2.
<(3) Image evaluation when 10,000 continuous images are output>
After 10,000 images of the test chart are output in succession, a full-tone cyan halftone image is output, and an abnormal image (local density such as black spots that occur when the image density decreases, density unevenness, or the photoconductor is damaged) The presence or absence of typical transfer unevenness) was observed. The results are shown in Table 2.
<(4) Evaluation of belt appearance at the time of continuous image output of 10,000 sheets>
After continuous output of 10,000 images of the test chart, the test chart was stopped and the presence or absence of defects in the surface layer of the intermediate transfer belt was observed with a laser microscope. The results are shown in Table 2.

  The intermediate transfer member of the present invention is flexible, has excellent toner releasability, can achieve a high transfer rate regardless of the type and surface shape of the recording medium, can be maintained for a long time, and the surface layer is durable. It can be used as an intermediate transfer belt of an image forming apparatus particularly suitable for full-color image formation because it can maintain a stable and high-quality image over a long period of time without causing damage to the organic photoreceptor. .

DESCRIPTION OF SYMBOLS 1 Base layer 2 Elastic layer 3 Surface layer 4 Spherical particle P Transfer paper L Exposure means 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photosensitive body cleaning apparatus 202 Static elimination lamp 203 Charging charger 204 Potential sensor 205 Toner image density sensor 210 Belt conveyance apparatus 230 revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C developing machine 231M M developing machine 270 fixing device 271, 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 502 toner seal member 503 charging charger 504 belt cleaning blade 505 lubricant Application brush 506 Lubricant 507 Primary transfer bias roller 508 Belt drive roller 509 Belt tension controller 510 Secondary transfer counter roller 511 Clear Rolling counter roller 512 Feedback current detection roller 513 Toner image 514 Optical sensor 600 Secondary transfer unit 601 Transfer paper guide plate 605 Secondary transfer bias roller 606 Transfer paper neutralization charger 608 Cleaning blade 610 Registration roller 801 Primary transfer power source 802 Secondary Transfer power source P Transfer paper 10 Printer body 12 Image writing unit 13 Image forming unit 14 Paper feed unit 15 Fixing device 16 Registration roller 20BK, 20M, 20Y, 20C Developing device 21BK, 21M, 21Y, 21C Photoconductor 22 Intermediate transfer belt 23BK , 23M, 23Y, 23C Primary transfer bias roller 25 Belt cleaning member 26 Belt driven roller 27 Lubricant coating device 40 Bias roller 50 Transfer conveyance belt 60 Secondary transfer bias low

JP-A-9-230717 JP 2002-162767 A JP 2004-354716 A JP 2007-328165 A JP 2009-75154 A Japanese Patent No. 3874360 Japanese Patent No. 3308741 Japanese Patent No. 3667030

Claims (8)

An intermediate transfer member to which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred,
The intermediate transfer member has a laminated structure including a base layer, an elastic layer, and a surface layer sequentially from the inside,
The surface layer contains spherical particles surface-treated with either a silicone-modified resin or a fluorine-modified resin, and any one of a silicone-modified resin and a fluorine-modified resin ,
The intermediate transfer member , wherein the resin contained in the surface layer and the resin that performs the surface treatment of the spherical particles are the same type of resin .   The intermediate transfer member according to claim 1, wherein the spherical particles are any of silicone particles and fluorine particles.   The intermediate transfer member according to claim 1, wherein the spherical particles have an average particle size of 5.0 μm or less.   The intermediate transfer member according to claim 1, wherein the average thickness of the surface layer is 10 μm or less.   The intermediate transfer member according to any one of claims 1 to 4, wherein the elastic layer is one of a thermosetting elastomer and a rubber material.   The intermediate transfer member according to any one of claims 1 to 5, wherein the base layer is one of a polyimide resin and a polyamideimide resin. An image carrier on which a latent image is formed and capable of carrying a toner image;
Developing means for developing the latent image formed on the image carrier with toner;
An intermediate transfer body on which a toner image developed by the developing means is primarily transferred;
Transfer means for secondary transfer of the toner image carried on the intermediate transfer member to a recording medium,
An image forming apparatus, wherein the intermediate transfer member is the intermediate transfer member according to claim 1. The image forming apparatus is a full-color image forming apparatus,
The image forming apparatus according to claim 7, wherein a plurality of latent image carriers having developing means for each color are arranged in series.