JP5418026B2 - Electrophotographic seamless belt and electrophotographic apparatus using the same - Google Patents

Description

  The present invention relates to a seamless belt for electrophotography, particularly an intermediate transfer belt used for full-color electrophotography, and an electrophotographic apparatus equipped with the intermediate transfer belt.

  In an electrophotographic apparatus, a seamless belt is used as a member for various functions and applications. Examples of such a seamless belt include a fixing belt, a transfer belt, and a paper conveyance belt. Among them, a full-color electrophotographic apparatus transfers a four-color toner image formed on a photoreceptor to an intermediate transfer belt to form a full-color image on the intermediate transfer belt, and then a transfer medium such as paper. An intermediate transfer belt used in a batch transfer method is a typical example.

  The demand for intermediate transfer belts is rapidly increasing as full-color copiers advance. Conventionally, materials such as thermoplastic resins, thermosetting resins, rubbers, and elastomers have been used as the intermediate transfer belt. In general, in a method using an intermediate transfer belt, a method called a tandem method in which color developing devices of respective colors facing the intermediate transfer belt are arranged in series to obtain high speed is the mainstream.

  The intermediate transfer belt used in this tandem system is required to have a high strength that can withstand repeated use without causing color misregistration due to deformation of the belt during running, and also requires flame retardancy. Polyimide and polyamideimide are preferably used. In particular, polyimide is preferably used from the viewpoint of creep deformation resistance and durability.

In a tandem electrophotographic apparatus (image forming apparatus), detection means using reflected light may be used for monitoring and controlling the overlapping position of each color and the image density. When using such a detection means, for example, the surface of the intermediate transfer belt that is running from a fixed position is irradiated with infrared light of a predetermined intensity, and the reflected light from the surface of the intermediate transfer belt at that time is detected by infrared reflected light. Monitoring and control are performed by detecting with an apparatus (light sensor). Therefore, a sufficiently high surface reflectance and gloss are required for the intermediate transfer belt provided in the image forming apparatus using such a detecting unit.
The above-mentioned polyimide resin has high surface reflectance and glossiness, and it can be said that it is also suitable as a material for the intermediate transfer belt in this respect.

  On the other hand, in recent years, there has been an increasing demand for high-performance image forming apparatuses that output a large amount of printed matter at a high speed, and accordingly, there is an increasing demand for high durability and long life of the intermediate transfer belt. In a tandem image forming apparatus, printing is performed by bringing a printing paper and an intermediate transfer belt into contact with each other. Therefore, if a large amount of printed material is passed at a high speed as described above, the belt may be damaged or worn. There was a problem. If the belt surface is damaged or worn in this way, the transferability is reduced, causing various abnormal images such as voids, uneven density, or uneven color, and the glossiness of the belt surface is reduced. There was a problem that it was.

  As a means for solving such a problem, a method of increasing the durability by laminating a surface layer on an intermediate transfer belt base layer is known, and this type of multi-layer high-performance intermediate transfer belt has been proposed. (For example, see Patent Documents 1 to 4).

For example, Patent Document 1 proposes using a cured methacrylic resin or a cured acrylic resin as a main component of the surface layer. However, it is necessary to provide an intermediate layer for improving adhesion between the base layer and the surface layer, and it is necessary to irradiate the surface layer with heat rays, actinic rays, electron beams, etc., which is disadvantageous in terms of productivity and cost. There is a problem. Further, since there is no technical description in consideration of glossiness control, problems remain in monitoring and controlling the color superposition position and image density by the above-described detection means using reflected light.
Patent Document 2 proposes that a surface layer containing a fiber such as PET or nylon is laminated in a fluororesin, and this makes it possible to obtain particularly excellent durability against cracking. However, the inclusion of fibers may impair the uniformity of the electrical characteristics of the belt, and also has the disadvantage of poor productivity. Patent Document 2 mainly focuses on improving durability against wear, and there is no technical description considering glossiness.
Patent Document 3 proposes that a layer in which a thermosetting resin of 300 ° C. or lower is cured with a curing agent is laminated on a thermoplastic base layer. Thereby, it is said that the abrasion resistance of the surface layer can be improved and the decrease in glossiness can be suppressed.
Patent Document 4 proposes a conductive endless belt having a laminated structure in which a base layer containing an inorganic filler and an outermost layer not containing an inorganic filler are formed by coextrusion. Thereby, it is said that it can be set as the surface layer excellent in glossiness.
However, in both Patent Document 3 and Patent Document 4, since a generally known thermoplastic resin (which does not include thermoplastic polyamide, polyimide, etc.) is used as the base layer, deformation or In addition to inferior production stability due to a change in resistance, heat resistance and mechanical properties are inferior to those of a base layer made of a thermosetting resin such as polyimide.

  In the above, when a material other than polyimide is used as a surface layer material to be laminated in order to enhance the durability of the intermediate transfer belt having polyimide as a base layer, there is a problem in that the adhesion to the base layer is poor. On the other hand, when a general polyimide-based resin is used for the surface layer, there is a disadvantage in terms of productivity and cost due to restrictions such as a short storage time of the material and a need to store at a low temperature.

  The present invention solves the above-mentioned problems of the prior art, is excellent in durability, wear resistance, and scratch resistance, maintains a surface glossiness suitable for detection means using reflected light, and has voids, uneven density, and uneven color. A long-life electrophotographic seamless belt that provides a high-quality full-color image without generating abnormal images such as an intermediate transfer belt of a full-color electrophotographic apparatus, and an electrophotographic apparatus (full-color electrophotographic apparatus using the same) ) Using materials with excellent productivity and cost.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [8], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above problem is a seamless belt for electrophotography in which at least a surface layer is provided on a base layer,
The surface layer is solved by an electrophotographic seamless belt characterized by containing, as a main component, a polyimide obtained by curing at least bisallylnadiimide represented by the following general formula (i).

  (In the formula (i), R represents a divalent hydrocarbon group having at least two carbon atoms.)

  [2]: The electrophotographic seamless belt according to the above [1], wherein the electrophotographic seamless belt is an electrophotographic intermediate transfer belt.

  [3]: In the electrophotographic seamless belt according to [1] or [2], R of the bisallylnadiimide represented by the general formula (i) is represented by the following chemical formulas (ii) to (iv): And at least one selected from divalent hydrocarbon groups.

  [4]: The electrophotographic seamless belt according to any one of [1] to [3], wherein the base layer is other than polyimide obtained by curing the bisallylnadiimide represented by the general formula (i). It contains polyimide as a main component.

  [5]: In the electrophotographic seamless belt according to [4] above, the polyimide other than the polyimide obtained by curing the bisallylnadiimide represented by the general formula (i) contains a polyamic acid in an organic solvent. It is obtained from a solution.

  [6]: In the seamless belt for electrophotography according to any one of [1] to [5], the surface layer includes at least carbon black, bisallylnadiimide represented by the general formula (i), and a solvent. It is formed by coating and heating with a carbon black dispersion liquid.

  [7]: The electrophotographic seamless belt according to [6] above, wherein the content of the carbon black in the surface layer is 2 wt% to 20 wt%.

[8]: The above problem is that primary transfer is performed by sequentially superimposing a plurality of color toner developed images sequentially formed on an image carrier on an intermediate transfer belt, and the primary transfer images are collectively recorded on a recording medium. In an electrophotographic apparatus for secondary transfer,
This is solved by an electrophotographic apparatus wherein the intermediate transfer belt is the electrophotographic seamless belt according to any one of [1] to [7].

According to the electrophotographic seamless belt of the present invention, on the base layer, a surface layer containing as a main component a polyimide formed by curing at least the bisallylnadiimide represented by the general formula (i) is provided. It is excellent in durability, wear resistance, and scratch resistance, and can maintain a surface glossiness suitable for detection means using reflected light.
That is, the electrophotographic seamless belt of the present invention having the above-described structure has a long life because of its small deformation and high strength even after repeated use, and even when used as an intermediate transfer belt of a full-color electrophotographic apparatus. Prevents abrasion and damage of the intermediate transfer belt surface due to paper, etc., maintains high transferability for a long time, and produces high-quality full-color images without generating abnormal images such as voids, uneven density, and uneven color. Can be formed.

FIG. 2 is a schematic diagram illustrating a schematic configuration of a main part for explaining an electrophotographic apparatus equipped with a belt constituent unit in which a seamless belt according to the present invention is used. FIG. 3 is a schematic diagram of a main part showing a configuration example in which a plurality of photosensitive drums are arranged in parallel along one seamless belt (intermediate transfer belt) according to the present invention provided in a belt constituent portion of an electrophotographic apparatus. .

As described above, the electrophotographic seamless belt in the present invention is an electrophotographic seamless belt having at least a surface layer on a base layer,
The surface layer contains at least a polyimide formed by curing bisallylnadiimide represented by the following general formula (i) as a main component.

  (In the formula (i), R represents a divalent hydrocarbon group containing at least 2 carbon atoms.)

  Here, the electrophotographic seamless belt is preferably an electrophotographic intermediate transfer belt.

  Moreover, it is preferable that R of the bisallyl nadiimide represented by the general formula (i) includes at least one selected from divalent hydrocarbon groups represented by the following chemical formulas (ii) to (iv).

The base layer and the surface layer constituting the electrophotographic seamless belt in the present invention will be described in detail below.
[Base layer]
As the base layer resin used for the base layer constituting the seamless belt for electrophotography of the present invention, any resin can be used as long as it does not undergo creep deformation during running and has strength and flame resistance that can withstand repeated use. However, polyimide that sufficiently satisfies these required characteristics is preferably used. That is, with the recent improvement in image quality and speed of full-color electrophotographic apparatuses, there is a need for dimensional stability and high strength so that no color shift occurs even as an intermediate transfer belt. From these points, polyimide is particularly preferable as the base layer. Hereinafter, the polyimide will be described as an example.

  As a polyimide used for the base layer of the electrophotographic seamless belt of the present invention, a polyimide other than a polyimide obtained by curing the bisallylnadiimide represented by the general formula (i) is used. Both types and thermosetting types can be used, but it is necessary to mix various materials as constituent components. In particular, polyamic acid (polyimide precursor) is used to mix a resistance modifier for adjusting electrical resistance. Body) in a polar organic solvent (coating solution: polyimide varnish), mixed with components and coated, heat treated and cyclized (imidized) to make polyimide Is preferred. In the present invention, a polyimide that requires cyclization (imidization) is referred to as a thermosetting polyimide.

The polyimide precursor for the composition of the coating liquid in the present invention and the base layer polyimide produced by heat treatment (imidization) of the precursor will be described in detail.
<Polyimide for base layer>
The polyimide for the base layer used in the present invention is first via a polyamic acid (polyimide precursor) by reaction of a generally known aromatic polycarboxylic acid anhydride or derivative thereof with an aromatic diamine. can get. That is, polyimide is generally insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, a polyimide precursor (polyamic acid or polyamic acid) that is soluble in an organic solvent is first synthesized from an acid anhydride and an aromatic diamine, and at this stage, molding processing is performed by various methods. A dehydration reaction is performed by heating or a chemical method to cyclize (imidize) to obtain polyimide. The outline of the reaction is shown in the following reaction formula (I).

(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.)

Specific examples of the aromatic polyvalent carboxylic acid anhydride having a tetravalent aromatic residue containing at least one carbon 6-membered ring include, for example, pyromellitic dianhydride, 3,3 ′, 4,4 '-Benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic 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 (2,3-dicarboxyphenyl) methane dianhydride, bis (3 , 4-Dicarboxy Enyl) methane dianhydride, 2,2-bis (3,4-dicarboxylphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic Acid dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic acid An anhydride etc. are mentioned. These may be used alone or in combination of two or more.
In addition, other (non-aromatic) polyvalent carboxylic acid anhydrides such as ethylenetetracarboxylic dianhydride and cyclopentanetetracarboxylic dianhydride are included in a range not impairing the object of the present invention (50 mol%). Can be used in combination.

  Next, specific examples of the aromatic diamine having a divalent aromatic residue containing at least one carbon 6-membered ring to be reacted with the aromatic polyvalent carboxylic acid anhydride include, 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-amino Phenyl) 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) 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) Enyl] propane, 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-hexafluoropropane, 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) phene Nyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) 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-a Nophenoxy) benzoyl] 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- And bis [4- (4-aminophenoxy) phenoxy] -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, and the like. These are used individually or in mixture of 2 or more types.

A polyimide precursor (polyamic acid) can be obtained by polymerizing the polycarboxylic acid anhydride component and the diamine component in an organic polar solvent using approximately equimolar amounts. Below, the manufacturing method of a polyamic acid is demonstrated concretely.
Examples of the organic polar solvent used in the polymerization reaction of polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N , N-dimethylacetamide, N, N-diethylacetamide and other acetamide solvents, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone and other pyrrolidone solvents, phenol, o-, m-, or p- Phenolic solvents such as cresol, xylenol, halogenated phenol, catechol, ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol, cellosolve such as butyl cellosolve or hex Methyl phosphoramide, .gamma.-butyrolactone, etc. may be mentioned, it is desirable to use them alone or as a mixed solvent. The solvent is not particularly limited as long as it dissolves polyamic acid, but N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable.

As an example of producing a polyimide precursor, first, one or a plurality of diamines are dissolved in the above organic solvent or dispersed in a slurry in an inert gas atmosphere such as argon or nitrogen. When at least one 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. A cyclopolyaddition reaction occurs, and the viscosity of the solution is rapidly increased, and a high molecular weight polyamic acid solution is obtained. The reaction temperature at this time is preferably controlled to −20 ° C. to 100 ° C., desirably 60 ° C. or less. The reaction time is about 30 minutes to 12 hours.
The above is an example. Contrary to the addition procedure in the reaction, the polycarboxylic acid anhydride or derivative thereof may be first dissolved or diffused in an organic solvent, and the diamine may be added to the solution. . 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. Furthermore, the tetracarboxylic dianhydride and the diamine may be simultaneously added to the organic polar solvent and allowed to react.

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

The polyimide precursor solution (polyamic acid solution) in the present invention can be synthesized as described above, but is simply a so-called polyamic acid composition dissolved in an organic solvent. What is marketed as a polyimide varnish can also be obtained and used.
Typical examples include Trenice (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries, Ltd.), Optmer (manufactured by JSR), SE812 (manufactured by Nissan Chemical Industries), CRC8000 (manufactured by Sumitomo Bakelite Co., Ltd.), and the like. It is mentioned as a thing.

  In addition, examples of the thermoplastic type include Aurum (Mitsui Chemicals) and Vespel (DuPont). Examples of the solvent-soluble type include Rika Coat (New Nippon Rika), block copolymerized polyimide (PI Engineering), GPI (Gunei Chemical Industry) and the like. These can be used by being added to and mixed with a thermosetting type polyimide as a subcomponent resin within a range that does not impair the target characteristics of the present invention.

  A base layer coating solution is prepared by blending the synthesized or obtained polyamic acid solution with a composition as required. After the base layer coating solution is applied to a support (molding mold), the polyimide precursor polyamic acid, which is a polyimide precursor, is converted (imidized) by a treatment such as heating.

  As a method for converting polyamic acid to polyimide, imidization can be performed by a method (1) only by heating or a chemical method (2). The heating only method (1) is a method of converting polyamic acid to polyimide by heat treatment at 200 to 350 ° C., and is a simple and practical method for obtaining polyimide. On the other hand, the chemical method (2) is a method in which a polyamic acid is reacted with a dehydrating cyclization reagent (such as a mixture of a carboxylic acid anhydride and a tertiary amine) and then heat-treated to completely imidize, (1 The method (1) is often used because it is a complicated and costly method compared to the heating only method. However, recently, although it is a kind of the method (2), a method of promoting imidization at the time of drying by incorporating an amine such as imidazole or quinoline in the varnish as a catalyst is often employed.

  In order to demonstrate the intrinsic performance of polyimide, it is necessary to complete the imidization by heating above the glass transition temperature of the corresponding polyimide, but this promotes imidization at a lower temperature. It is said that mechanical durability is also improved. However, these catalysts are in very small amounts, and some of them decompose and sublime during drying, but some remain as impurities, which is not preferable.

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

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

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 the characteristic absorptions of imide and 1,015 cm ^-1 of characteristic absorption of benzene ring (2) Characteristics of imide Absorbance ratio between 1,380 cm ^-1 (an azimuthal vibration band of imide ring CN group), which is one of the absorptions, and 1,500 cm ^-1 characteristic absorption of the benzene ring (3) One of the characteristic absorptions of imide Absorption ratio of 1,720 cm ^-1 (immobilization vibration 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 characteristic absorption of amide group 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and CN stretching vibration) and amide group over 3000 to 3300 cm ⁻¹ If it is confirmed that the multiple absorption band of the origin has disappeared, further imidization Reliability of the binding is enhanced.

In the base layer coating solution for forming the base layer of the present invention, another resin may be used in combination with the polyimide. Further, various materials for imparting a necessary function as an intermediate transfer belt are blended.
As a material to be blended, for example, a resistance adjusting agent, a reinforcing material, a leveling agent, a surfactant, a lubricant, an antioxidant, a catalyst, and the like can be blended. Of these, the resistance adjusting agent is particularly important.

Next, the resistance adjuster will be described. The resistance adjuster is indispensable for adjusting the intermediate transfer belt to a predetermined resistance value.
Any resistance adjusting agent can be used as long as it can adjust the resistance value of polyimide. For example, carbon black, graphite, or metals such as copper, tin, aluminum, indium, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin doped Fillers such as metal oxide fine powders such as indium oxide, conductive polymer materials such as polyetheramide, polyetheresteramide, polypyrrole, polythiophene, polyaniline, tetraalkylammonium salt, trialkylbenzyl, ammonium Salt, alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate, glycerol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty alcohol ester, alkyl Tyne, may be used an ion-conductive material, such as lithium perchlorate. These can also be used in combination. In addition, the resistance adjusting agent in the present invention is not limited to these exemplary compounds.

In the base layer of the electrophotographic seamless belt of the present invention, carbon black is preferably used among the resistance adjusting agents.
Examples of carbon black include furnace black, acetylene black, ketjen black, and channel black. Oxidized carbon black obtained by oxidizing these surfaces is preferable. Moreover, you may use a dispersing aid as needed. Furthermore, the surface functional group of carbon black and an organic compound having reactivity with the functional group may be surface-treated.

Next, a method for forming the base layer of the seamless belt using the base layer coating solution containing the polyimide precursor will be described. For example, the base layer is formed by the following process.
A dispersion preparing step for dispersing a resistance adjusting agent in a polyamic acid solution, a coating solution preparing step for adjusting a dispersion obtained by the step to a predetermined resistance adjusting agent content, and a coating solution prepared by the step The step of applying and casting to (molding mold), the step of removing the solvent in the coating applied and cast on the support by heating, the precursor imide contained in the coating by heating at elevated temperature The base layer is formed by the step of promoting the conversion. Next, a surface layer is provided on the formed thin film (base layer) to produce a seamless belt.

In the step of dispersing the resistance adjusting agent, there are a method in which the resistance adjusting agent is directly dispersed and mixed in the polyimide precursor solution, or a method in which the resistance controlling agent is previously dispersed in a solvent and then mixed with the polyimide precursor solution.
Here, a method for dispersing carbon black as a resistance adjusting agent will be described below as an example. In addition, the following is an example and it is not limited to this.

N-methyl-2-pyrrolidone is mixed with a small amount of carbon black and a polyimide precursor, and dispersed in a ball mill, paint shaker, bead mill or the like for a predetermined time using zirconia beads. After being dispersed to a certain particle size, the liquid taken out is used as a dispersion.
The polyimide precursor solution is mixed with the dispersion to dilute to a predetermined carbon black concentration. As a mixing method at this time, a centrifugal stirrer, a Henschel mixer, a homogenizer, a planetary stirrer, or the like can be used.
If necessary, additives such as a leveling agent and a catalyst can be added at this time.
Further, after stirring, it is preferable to defoam using a vacuum defoamer or the like.

Next, the process of applying the base layer coating solution prepared above will be described.
Examples of the method for forming a film on the support include centrifugal molding, roll coating, blade coating, ring coating, dipping, spray coating, dispenser coating, and die coating.
Centrifugal molding can be used as a method of forming the base layer of the seamless belt from polyimide. However, in the centrifugal molding method, since the base layer coating solution is applied to the inner surface of the support to form a film, another layer (for example, a surface layer when directly forming the surface layer) is laminated on the surface of the base layer. In this case, after forming the base layer, it is necessary to remove the mold once, transfer the base layer to another mold, and form a surface layer by another coating method, which complicates the process.
For this reason, in the case of a seamless belt structure for electrophotography in which at least a surface layer is provided on the base layer of the present invention, a base layer is formed by applying a base layer coating solution on the outer surface of the support, and if necessary, an intermediate layer is formed. It is preferable to sequentially laminate the surface layer with a layer or the like interposed therebetween, and as such a method, roll coating, dispenser coating, ring coating, die coating, or spray coating is preferably used.

  After applying a coating solution containing polyamic acid to a predetermined film thickness on the outer surface of a support (metal cylindrical support) coated with a release agent in advance by the above method, using a hot air dryer, IH heater, far infrared heater, etc. Dry the coating. In drying, first, drying is performed at a temperature of about 80 to 120 ° C. for 10 to 60 minutes, and then the temperature is increased at a temperature rising rate of about 2 to 5 ° C./min, and imidization baking is performed at 300 to 400 ° C. Do. Then, after sufficiently cooling, the surface layer is applied. It should be noted that other layers other than the base layer, such as the surface layer and the intermediate layer provided if necessary, do not necessarily have to be formed by the same method.

As a film thickness of the base layer formed by this invention, 50-100 micrometers is preferable. If the film thickness is too thin, the strength is insufficient and the durability is inferior, and if it is too thick, the rigidity is too large to be stably driven by a driving roller having a small curvature. The content of the carbon black used as a resistance adjusting agent, preferably 5-25 wt%, it is preferable that a 10 ⁶ to 10 ¹⁰ [Omega] cm as volume resistivity. If the carbon black content is too small, it is difficult to control the variation in resistance value. If the carbon black content is too large, the film is brittle and inferior in flexibility and inferior in durability. If the resistance value is too low, the toner is scattered in the non-image area at the time of transfer and the sharpness is lowered. On the other hand, if it is too high, the transfer electric field does not work well, which is not preferable in terms of transfer efficiency.

[Surface layer]
Next, the surface layer constituting the electrophotographic seamless belt of the present invention will be described.
As described above, the surface layer in the present invention contains at least a polyimide obtained by curing bisallylnadiimide represented by the general formula (i) as a main component.
Here, R in the formula (i) represents a divalent hydrocarbon group having at least two carbon atoms. Examples of the divalent hydrocarbon group include an alkylene group, an arylene group, an aralkylene group, and the like. The divalent hydrocarbon groups represented by the chemical formulas (ii) to (iv) are preferably used. Note that the alkylene group, arylene group, aralkylene group, and the like may have a hetero atom such as an oxygen atom or a nitrogen atom in the bond, or may have a substituent.

What is marketed as said bisallyl nadiimide can be used.
For example, as the R part of the general formula (i) corresponds to the chemical formula (ii), BANI-M of Maruzen Petrochemical Co., Ltd., the R part of the general formula (i) corresponds to the chemical formula (iii) As examples, BANI-H of Maruzen Petrochemical Co., Ltd., and BANI-X of Maruzen Petrochemical Co., Ltd. can be cited as the R portion of the chemical formula (i) corresponding to the chemical formula (iv).

Bisallyl nadiimide proceeds and cures by the addition reaction of double bonds in the allyl group and the norbornene skeleton to form a three-dimensional crosslinked structure. That is, the reaction of bisallyl nadiimide proceeds by heating as in the case of a normal thermosetting resin.
The obtained cured bisallylnadiimide has an appropriate hardness, improves the abrasion resistance and scratch resistance of the electrophotographic seamless belt surface layer, and reflects the reflected light in the electrophotographic apparatus equipped with the belt. The surface glossiness [20 ° glossiness on the surface is 60 to 200] suitable for the used detection means can be maintained, so that the detection sensor does not have a problem and the life can be extended.
The 20 ° glossiness on the surface is a value measured by a gloss meter PG-1 [Nippon Denshoku Industries Co., Ltd.] [measurement area is 10.0 × 10.6 mm ² ].

  The bisallyl nadiimide has a low melting point and is soluble in most organic solvents except aliphatic hydrocarbons and aliphatic alcohols. Therefore, a surface layer can be formed on the base layer by the same coating method as described in the above “base layer” by using a solution (surface layer coating solution) in which bisallylnadiimide is dissolved in an organic solvent. it can. If a coating film is formed on the base layer using the surface layer coating solution, it is suitable for continuous production. Further, the surface layer coating liquid can be adjusted in viscosity with a solvent or the like as required, and various additive materials can be easily blended. As a material to be blended, for example, a resistance adjusting agent, a reinforcing material, a leveling agent, a surfactant, a lubricant, an antioxidant, a catalyst, and the like can be blended.

Among these, a particularly important formulation of the resistance adjusting agent will be described. As the resistance adjusting agent, the same ones as described above can be applied. In particular, carbon black is preferably used. The bisallyl nadiimide of the present invention has a good dispersibility with respect to carbon black and is easy to be obtained with a small variation in resistance.
Here, a method of dispersing carbon black as a resistance control agent will be described as an example. In addition, the following is an example and it is not limited to this.

Carbon black and a small amount of bisallylnadiimide are mixed with N-methyl-2-pyrrolidone, and dispersed in a ball mill, paint shaker, bead mill or the like for a predetermined time using zirconia beads. After being dispersed to a certain particle size, the liquid taken out is used as a dispersion.
By diluting the dispersion with bisallylnadiimide, the dispersion is diluted to a predetermined carbon black concentration. As a mixing method at this time, a centrifugal stirrer, a Henschel mixer, a homogenizer, a planetary stirrer, or the like can be used.
If necessary, additives such as a leveling agent and a catalyst can be added at this time. Further, after stirring, it is preferable to defoam using a vacuum defoamer or the like.

  Next, the obtained surface layer coating solution is applied so as to have a predetermined film thickness on the base layer (including the base layer polyimide) by selecting a method suitably selected from the same method as described above. To do. Although the final film thickness is not particularly limited, it is preferably about 0.5 to 50 μm, more preferably about 1 to 20 μm.

  After applying the surface layer coating solution, it is cured by heating in a dryer. First, it is dried for 10 to 60 minutes at a temperature of about 80 to 120 ° C., and then heated at a rate of temperature increase of about 2 to 5 ° C./min, and heated at a temperature of about 200 to 400 ° C. for several hours, It is preferable to cure. After heating, it is cooled and removed from the mold to obtain a seamless belt.

  In the above description of the seamless belt for electrophotography, the description has been mainly made of the two-layer configuration of the base layer and the surface layer. However, the configuration is not necessarily limited to the two-layer configuration, for example, between the base layer and the surface layer. You may laminate | stack in multiple layers as needed, such as providing an intermediate | middle layer.

  The seamless belt for electrophotography of the present invention is suitably used as an intermediate transfer belt of an electrophotographic apparatus (particularly, a full-color electrophotographic apparatus) because it has little deformation even after repeated use and has durability. That is, even when used as an intermediate transfer belt of a full-color electrophotographic apparatus, wear and damage of the surface of the intermediate transfer belt due to paper passing or the like is prevented, and high transferability is maintained over a long period of time. As a result, a high-quality full-color image can be output without generating abnormal images (such as voids, uneven density, and uneven color).

The seamless belt of the present invention used in the belt constituting unit equipped in the electrophotographic apparatus will be described in detail below 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.
The schematic diagram of FIG. 1 shows a schematic configuration of a main part for explaining an electrophotographic apparatus equipped with a belt constituting portion in which a seamless belt according to the present invention is used.
The intermediate transfer unit (500) which is a belt component shown in FIG. 1 includes an intermediate transfer belt (501) which is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt (501), there are a secondary transfer bias roller (605) as a secondary transfer charge applying means of the secondary transfer unit (600), and a belt cleaning blade (504) as an intermediate transfer body cleaning means. A lubricant application brush (505), which is a lubricant application member of the lubricant application means, is disposed so as to face each other.

  Further, a position detection mark (not shown) is 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. In this case, a position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt (501).

  The 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) on which the intermediate transfer belt (501) is stretched. Position detection is performed by detecting light reflection from the surface of the intermediate transfer belt. For this reason, detection is not stable when the glossiness of the surface of the intermediate transfer belt decreases or becomes non-uniform, but the use of the seamless belt (intermediate transfer belt) of the present invention can suppress the decrease in surface glossiness and detect it. Can be stabilized.

  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), which are primary transfer charge applying means, and a cleaning device. It is stretched between the counter roller (511) and the feedback current detection roller (512). Each roller is made of a conductive material, and each roller other than the primary transfer bias roller (507) is grounded. The primary transfer bias roller (507) is controlled by a primary transfer power source (801) controlled by a constant current or a constant voltage so that the current or voltage is controlled to a predetermined magnitude according to the number of superimposed toner images. A bias is applied.

  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), which is the belt component, is usually a semiconductor or insulator and has a single layer or multilayer structure, but the seamless belt of the present invention is preferably used, thereby improving durability. In addition, excellent image formation can be realized. In addition, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose the toner images formed on the photosensitive drum (200).

  A secondary transfer bias roller (605), which is a secondary transfer means, is in contact with / separating means, which will be described later, with respect to the belt outer peripheral surface of a portion of the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510). It is comprised so that contact / separation is possible by the contact / separation mechanism. 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). A transfer bias having a predetermined current is applied by a secondary transfer power source (802) controlled at a constant current.

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

  In the color copying machine having such a configuration, when the image forming cycle is started, the photosensitive drum (200) is rotated in the counterclockwise direction indicated by an arrow by a drive motor (not shown), and a charging charger is used according to each color. After charging by (203) and image exposure by the exposure means (L), Bk (black) toner image formation, C (cyan) toner image formation, M (magenta) toner image formation on the photosensitive drum (200) , Y (yellow) toner image formation is 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, 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. 1, 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 charged uniformly, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing machine (231K) comes into contact with this Bk electrostatic latent image, the toner adheres to the portion where the charge of the photosensitive drum (200) remains. In other words, toner is attracted to a portion having no charge, that is, an 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 way is primary on the belt outer peripheral surface of the intermediate transfer belt (501) rotating at a constant speed while being in contact with the photosensitive drum (200). Transcribed. 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). Is done. On the photosensitive drum (200) side, the process proceeds to the C image forming process after the Bk image forming process, and reading of the C image data by the color scanner starts at a predetermined timing. A C electrostatic latent image is formed on the surface of the body drum (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 reaches, the revolver developing unit (230) is rotated, and the C developing machine ( 231C) is set at the development position, and the C electrostatic latent image is developed with C toner. Thereafter, development of the C electrostatic latent image area is continued, but when the rear end portion of the C electrostatic latent image passes, the revolver developing unit is rotated as in the case of the previous Bk developing machine (231K). Then, the next 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).
Then, on the intermediate transfer belt (501), the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510) and the secondary transfer bias roller (605) form a nip. When the leading edge of the toner image approaches, 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 is transferred along the transfer paper guide plate (601). The paper (P) is conveyed and registration of the transfer paper (P) and the toner image is performed.

  In this way, when the transfer paper (P) passes through the secondary transfer portion, the intermediate transfer belt (501) is transferred by the transfer bias due to the voltage applied to the secondary transfer bias roller (605) by the secondary transfer power source (802). ) The four-color superimposed toner image on the top is transferred onto the transfer paper (P) at once (secondary transfer). Conventionally, plain paper that is relatively smooth has been used as this transfer paper, but in recent years, paper with relatively rough surface properties such as recycled paper has also been used. Furthermore, photographic images are often printed using a wide variety of paper such as coated paper and embossed paper. In particular, when a paper having unevenness and patterns on its surface such as embossed paper is used, there is a problem that the toner image cannot be transferred well due to the unevenness. A conventional intermediate transfer belt made of polyimide cannot follow this uneven shape, and thus toner is not transferred to the concave portion, resulting in uneven transfer. This phenomenon results in an uneven color image having a different color tone on the pattern, particularly in a color portion where two or more colors overlap. By using the intermediate transfer belt of the present invention, it is possible to realize good transfer without causing unevenness due to the unevenness of the paper.

  This transfer paper (P) is conveyed along the transfer paper guide plate (601) and passes through a portion facing the transfer paper neutralization charger (606) comprising a static elimination needle disposed downstream of the secondary transfer portion. After being neutralized by this, the belt is conveyed toward the fixing device (270) by the belt conveying device (210) which is a belt component (see FIG. 1). Then, after the toner image is melted and fixed at the nip portion 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). Stacked face up on a copy tray (not shown). 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). The 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 contact and separate at a predetermined timing with respect to the belt outer peripheral surface of the intermediate transfer belt (501) 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) contacting and separating from the belt outer peripheral surface of the intermediate transfer belt (501) is provided. Yes. The toner seal member (502) receives the falling toner that has dropped from the belt cleaning blade (504) during cleaning of the residual toner, and prevents the falling toner from scattering on the transfer path of the transfer paper (P). It is preventing. 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 belt 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). This lubricant application mechanism is intended to maintain the transfer performance or cleaning performance in a good condition over the long term, but if this function is not necessary depending on the performance of the intermediate transfer belt, it is not necessary to use this function. Good. 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) 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 and out of contact with the outer peripheral surface of the intermediate transfer belt (501) at a predetermined timing by a contact / separation mechanism (not shown). It has become.

Here, at the time of repeat copying, 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 forming process. The process proceeds to the image forming process for the first color (Bk). The intermediate transfer belt (501) has two sheets 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 Bk toner image of the eye is primarily 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 number of times. In the case of the single color copy mode, only the developing device of the predetermined color 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 moved to the intermediate transfer belt (501). The copy operation is performed with the touch panel kept in contact.
In FIG. 1, reference numeral 70 denotes a static elimination roller, 80 denotes a ground roller, 204 denotes a potential sensor, 205 denotes a toner image density sensor, 503 denotes a charging charger, and 513 denotes a toner image.

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

  In FIG. 2, 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 electrophotography. Based on the image signal, the image processing unit converts the image signal into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation, and the image writing unit (12). Send to. 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, and corresponds to each color signal described above. An image document corresponding to each color signal is provided in an image carrier (photosensitive member) (21BK), (21M), (21Y), and (21C) having four writing optical paths and provided for each color of the image forming unit. Doing

  The image forming unit (13) is a photoconductor (21BK), (21M), (21Y) which is an image carrier for black (BK), magenta (M), yellow (Y), and cyan (C). ), (21C). As each photoconductor for each color, an OPC photoconductor is usually used. Around each of the photosensitive members (21BK), (21M), (21Y), and (21C), there are a charging device, a laser beam exposure unit from the writing unit (12), and each color of black, magenta, yellow, and cyan Developing devices (20BK), (20M), (20Y), (20C), primary transfer bias rollers (23BK) as primary transfer means, (23M), (23Y), (23C), cleaning devices ( (Not shown), and a photosensitive member neutralizing device (not shown) are provided. 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, includes the photosensitive members (21BK), (21M), (21Y), and (21C) and the primary transfer bias rollers (23BK), (23M), and (23Y). , (23C), and the toner images of the respective colors formed on the respective photoreceptors are sequentially superimposed and transferred.

  On the other hand, the transfer paper (P) is fed from the paper feed section (14) and then carried by the transfer conveyance belt (50), which is a belt constituting section, via the registration rollers (16). When the intermediate transfer belt (22) and the transfer conveying belt (50) come into contact with each other, the toner image transferred onto the intermediate transfer belt (22) is transferred to a secondary transfer bias roller (60) as a secondary transfer unit. ) For secondary transfer (collective transfer). Thereby, 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). After the image transferred by the fixing device (15) is fixed, the transfer paper (P) is removed from the printer main body. To be discharged.

  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 device (25). A lubricant application device (not shown) is disposed on the downstream side of the belt cleaning device (25). This lubricant application device 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.

Further, position detection marks (not shown) are provided on the outer peripheral surface or inner peripheral surface of the intermediate transfer belt (22). However, on the outer peripheral surface side of the intermediate transfer belt (22), it is necessary to devise a position detection mark that avoids the passing area of the belt cleaning device (25), which may be difficult to arrange. In this case, a position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt (22). The optical sensor (28) as a mark detection sensor is provided at a position between the secondary transfer bias roller (60) and the belt drive roller (24). Position detection is performed by detecting light reflection from the surface of the intermediate transfer belt. Therefore, detection becomes unstable when the glossiness of the surface of the intermediate transfer belt decreases or becomes non-uniform. By using the intermediate transfer belt of the present invention, it is possible to suppress a decrease in surface glossiness and to stabilize detection.
2, reference numeral 26 denotes a belt driven roller, 27 denotes a lubricant application device, and 70 denotes a bias roller.

  The seamless belt in the present invention can be suitably applied to an intermediate transfer belt type image forming apparatus equipped with the intermediate transfer belt (501) or (22) as described above, and the intermediate transfer belt (501) or (22). Instead of this, the present invention can also be applied to a transfer and conveyance belt type image forming apparatus equipped with a transfer and conveyance belt. Further, in the case of an image forming apparatus using a transfer / conveying belt system, the present invention can be applied to either the 1-photosensitive drum system or the 4-photosensitive drum system.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples without departing from the gist thereof.

[Example 1]
[Preparation of Intermediate Transfer Belt A]
(Preparation of base layer coating solution A)
First, the constituent materials shown below were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion A for base layer.
<Constituent material of carbon dispersion A for base layer>
Polyimide solution U-varnish A (Ube Industries, solid content 18%): 2 parts by weight Carbon black Special black 4 (Degussa): 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical): 88 parts by weight

Using the carbon dispersion A for base layer, constituent materials were mixed according to the following formulation, and mixed and defoamed with a centrifugal stirring deaerator to obtain a base layer coating liquid A.
<Constituent material of coating liquid A for base layer>
-Carbon dispersion A for base layer: 50 parts by weight-Polyimide solution U-varnish A (Ube Industries; solid content 18 wt%): 50 parts by weight-Polyether-modified silicone FZ2105 (Toray Dow Corning): 0.01 parts by weight

(Formation of base layer)
Next, a metal cylinder having an outer diameter of 100 mm and a length of 300 mm having a mirror finish and a release agent applied thereto is used as a mold, and the cylinder is rotated at 50 rpm (times / minute) while the base layer is used. The coating liquid A was cast and applied uniformly on the outer surface of the cylinder using a dispenser. The coating amount was such that the final film thickness was 70 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 100 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 310 ° C. at a heating rate of 2 ° C./min, and subjected to heat treatment (baking) for 60 minutes. After stopping the heating, it was gradually cooled to room temperature to form a base layer on the metal cylindrical outer surface.

(Preparation of surface layer coating solution A)
First, the following constituent materials were mixed and dispersed using a zirconia bead having a diameter of 1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion A for the surface layer.
<Constituent material of carbon dispersion A for surface layer>
・ Bisallyl nadiimide solution BANI-X
(Maruzen Petrochemical; solid content 50 wt%): 1 part by weight Carbon black Special black 4 (Degussa): 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical): 89 parts by weight

  Using the surface layer carbon dispersion A, the constituent materials were mixed according to the following formulation, and mixed and defoamed with a centrifugal stirring deaerator to obtain a surface layer coating liquid A.

<Constituent material of surface layer coating liquid A>
-Carbon dispersion A for surface layer: 20 parts by weight-Bisallyl nadiimide solution BANI-X
(Maruzen Petrochemical; solid content 50 wt%): 80 parts by weight Polyether-modified silicone FZ2105
(Toray Dow Corning): 0.01 parts by weight

[Formation of surface layer A on the base layer]
The surface layer coating solution A was uniformly cast and applied to the outer surface of the polyimide base layer formed on the metal cylindrical mold using a dispenser, as in the case of the base layer. The coating amount was such that the final film thickness was 5 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 110 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Then, it heated up to 300 degreeC with the temperature increase rate of 3 degree-C / min, and heat-processed for 120 minutes. After stopping the heating, it was gradually cooled to room temperature, and the seamless belt having the surface layer A formed on the base layer was removed from the metal cylinder to obtain an intermediate transfer belt A.

[Example 2]
[Preparation of intermediate transfer belt B]
A surface layer was formed on the base layer formed in the same manner as in Example 1 using the following surface layer coating solution B, whereby an intermediate transfer belt B was obtained.

(Preparation of surface layer coating solution B)
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion B for the surface layer.
<Constituent material of carbon dispersion B for surface layer>
・ Bisallyl nadiimide solution BANI-M
(Maruzen Petrochemical; solid content 50 wt%): 1 part by weight Carbon black Special black 4 (Degussa): 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical): 89 parts by weight

  Using the surface layer carbon dispersion B, the constituent materials were mixed according to the following formulation, and mixed and defoamed with a centrifugal stirring deaerator to obtain a surface layer coating liquid B.

<Constituent material of surface layer coating liquid B>
-Carbon dispersion B for surface layer: 22 parts by weight-Bisallyl nadiimide solution BANI-M
(Maruzen Petrochemical; solid content 50 wt%): 78 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning): 0.01 parts by weight

[Formation of surface layer B on base layer]
In the same manner as in Example 1, the surface layer coating liquid B was uniformly applied to the outer surface of the polyimide base layer formed on the metal cylinder using the base layer coating liquid A in the same manner as in the case of the base layer. Then, it was cast and applied. The coating amount was such that the final film thickness was 10 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 110 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Then, it heated up to 300 degreeC with the temperature increase rate of 3 degree-C / min, and heat-processed for 120 minutes. After stopping the heating, it was gradually cooled to room temperature, and the seamless belt having the surface layer B formed on the base layer was removed from the metal cylinder to obtain an intermediate transfer belt B.

[Example 3]
[Preparation of intermediate transfer belt C]
A surface layer was formed on the base layer formed in the same manner as in Example 1 using the following surface layer coating solution C, whereby an intermediate transfer belt C was obtained.

(Preparation of surface layer coating solution C)
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion C for the surface layer.
<Constituent material of carbon dispersion C for surface layer>
・ Bisallyl nadiimide solution BANI-H
(Maruzen Petrochemical; solid content 50 wt%): 1 part by weight Carbon black Special black 4 (Degussa): 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical): 89 parts by weight

  Using the surface layer carbon dispersion C, constituent materials were mixed according to the following formulation, and mixed and defoamed using a centrifugal stirring deaerator to obtain a surface layer coating liquid C.

<Constituent material of surface layer coating liquid C>
-Carbon dispersion C for surface layer: 19 parts by weight-Bisallyl nadiimide solution BANI-H
(Maruzen Petrochemical; solid content 50 wt%): 81 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning): 0.01 parts by weight

[Formation of surface layer C on base layer]
In the same manner as in Example 1, the surface layer coating liquid C was uniformly applied to the outer surface of the polyimide base layer formed on the metal cylinder using the base layer coating liquid A in the same manner as in the case of the base layer. Then, it was cast and applied. The coating amount was such that the final film thickness was 10 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 110 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Then, it heated up to 300 degreeC with the temperature increase rate of 3 degree-C / min, and heat-processed for 120 minutes. After stopping the heating, it was gradually cooled to room temperature, and the seamless belt having the surface layer C formed on the base layer was removed from the metal cylinder to obtain an intermediate transfer belt C.

[Example 4]
[Preparation of intermediate transfer belt D]
A surface layer was formed on the base layer formed in the same manner as in Example 1 using the following surface layer coating solution D, whereby an intermediate transfer belt D was obtained.

(Preparation of surface layer coating solution D)
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a surface layer carbon dispersion D.
<Constituent material of carbon dispersion D for surface layer>
・ Bisallyl nadiimide solution BANI-X
(Maruzen Petrochemical; solid content 50 wt%): 1 part by weight Carbon black Special black 4 (Degussa): 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical): 89 parts by weight

  Using the surface layer carbon dispersion D, constituent materials were mixed according to the following formulation, and mixed and degassed with a centrifugal stirring deaerator to obtain a surface layer coating liquid D.

<Constituent material of coating liquid D for surface layer>
-Carbon dispersion D for surface layer: 50 parts by weight-Bisallyl nadiimide solution BANI-X
(Maruzen Petrochemical; solid content 50 wt%): 50 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning): 0.01 parts by weight

[Formation of surface layer D on base layer]
In the same manner as in Example 1, the surface layer coating liquid D was uniformly applied to the outer surface of the polyimide base layer formed on the metal cylinder using the base layer coating liquid A in the same manner as in the case of the base layer. Then, it was cast and applied. The coating amount was such that the final film thickness was 10 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 110 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Then, it heated up to 300 degreeC with the temperature increase rate of 3 degree-C / min, and heat-processed for 120 minutes. After stopping the heating, it was gradually cooled to room temperature, and the seamless belt having the surface layer D formed on the base layer was removed from the metal cylinder to obtain an intermediate transfer belt D.

[Comparative Example 1]
[Preparation of intermediate transfer belt E]
In the intermediate transfer belt A of Example 1, Example 1 except that the surface layer was formed in place of the resin material obtained by mixing the bisallylnadiimide used in the preparation of the surface layer coating liquid A with the following composition. Similarly, an intermediate transfer belt E was obtained.
<Composition of resin material>
-Urethane-modified copolymer polyester resin (Byron UR1350; Toyobo): 100 parts by weight-TDI-modified isocyanate curing agent Coronate L (Japan Polyurethane Industry) 7 parts by weight

[Comparative Example 2]
[Preparation of intermediate transfer belt F]
In the intermediate transfer belt A of Example 1, Example 1 except that the surface layer was formed in place of the resin material obtained by mixing the bisallylnadiimide used in the preparation of the surface layer coating liquid A with the following composition. Similarly, an intermediate transfer belt F was obtained.
<Composition of resin material>
Polyimide solution U-varnish S (Ube Industries; solid content 18.5 wt%): 50 parts by weight

[Comparative Example 3]
[Preparation of intermediate transfer belt G]
An intermediate transfer belt G was obtained in the same manner as in Example 1 except that the intermediate transfer belt A of Example 1 had a single-layer structure having only a base layer without a surface layer.

Each of the intermediate transfer belts of Examples 1 to 4 and Comparative Examples 1 to 3 is installed as an intermediate transfer belt of the electrophotographic apparatus shown in FIG. 2, and after standing for one week, a solid image of cyan is printed and printed. The image density (ID) of the solid image was measured.
Thereafter, each intermediate transfer belt was taken out, and the glossiness of the surface (20 ° glossiness) was measured. The surface was again equipped as an intermediate transfer belt, and continuous 10,000 sheets were printed. Thereafter, the seamless belt was taken out, and the 20 ° glossiness of the surface was measured again. Further, the image density of the solid image printed last was measured.
TYPE 6200 (Ricoh) was used as the printing paper.
A gloss meter PG-1 (Nippon Denshoku Industries Co., Ltd.) was used for the measurement of glossiness. The measurement area is 10.0 × 10.6 mm ² .
A spectral density measuring device X-Rite (model 520 X-Rite) was used for image density measurement.
Each measurement result is shown in Table 1 below.

As shown in Table 1, in Comparative Example 1, the test was interrupted because the surface layer was peeled off during the continuous output test. In Examples 1 to 4, such a phenomenon did not occur, and it was confirmed that the surface layer used in the present invention was excellent in adhesion to the base layer and could withstand long-term use.
In Comparative Example 2, since a polyimide surface layer was applied, no significant reduction in image density (ID) or glossiness occurred. However, the density unevenness was particularly remarkable during halftone output. This is considered to be because the carbon black dispersibility of the polyimide used for the surface layer was poor and the resistance variation was large. On the other hand, in Examples 1-4, such an abnormal image was not seen.
As a result of measuring the image density before and after the continuous output test, the ID decreased in all cases due to deterioration of the developer and the like, but compared with Comparative Example 3 having no surface layer, the bisallyl nadiimide of the present invention. In Examples 1 to 4 provided with a surface layer containing as a main component a polyimide obtained by curing the material, the degree of ID reduction was clearly small. That is, it was confirmed that it is possible to suppress a decrease in transferability by providing the surface layer of the present invention. Further, in Comparative Example 3, abnormal images such as voids and uneven density were confirmed.
Further, considering that the required 20 ° glossiness of the belt surface is in the range of 60 to 200, and more preferably in the range, 80 to 150, before and after the print output shown in Table 1, From the results of the 20 ° gloss measurement on the surface, it can be said that the glossiness is sufficiently maintained in Examples 1 to 4, and the wear resistance and scratch resistance are excellent.
From the above, according to the present invention, it is excellent in wear resistance and scratch resistance, maintains a certain surface glossiness and a high transfer rate and transfer performance, has no abnormal images such as voids and uneven density, and has high quality. It was confirmed that a seamless belt for electrophotography suitable for an intermediate transfer belt can be obtained with a long lifetime capable of realizing a full-color image.
If such a seamless belt for electrophotography is used, it is possible to cope with high speed, full color, high image quality, etc., which are strongly demanded in electrophotographic apparatuses (image forming apparatuses) such as copying machines, laser printers or ordinary facsimiles. Can do.

(Figure 1)
P transfer paper L exposure means 70 discharging roller 80 ground roller 200 photosensitive drum 201 photosensitive member cleaning device 202 discharging lamp 203 charging charger 204 potential sensor 205 toner image density sensor 210 belt conveying device 230 revolver developing unit 231Y Y developing device 231K Bk developing Machine 231C C developing machine 231M M developing machine 270 fixing device 271 and 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 Cleaning counter roller 512 Feedback Current transfer roller 513 Toner image 514 Optical sensor 600 Secondary transfer unit 601 Transfer paper guide plate 605 Secondary transfer bias roller 606 Transfer paper discharger 608 Cleaning blade 610 Registration roller 801 Primary transfer power source 802 Secondary transfer power source (FIG. 2) )
P Transfer paper 10 Printer body 12 Image writing unit 13 Image forming unit 14 Paper feeding 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 24 Belt drive roller 25 Belt cleaning member 26 Belt driven roller 27 Lubricant coating device 28 Optical sensor 50 Transfer conveyance belt 60 Secondary transfer bias roller 70 Bias roller

JP 2007-316622 A JP 2004-039552 A JP 2005-266793 A JP 2009-25786 A

Claims (8)

A seamless belt for electrophotography in which at least a surface layer is provided on a base layer,
The seamless belt for electrophotography, wherein the surface layer contains at least a polyimide obtained by curing bisallylnadiimide represented by the following general formula (i).

(In the formula (i), R represents a divalent hydrocarbon group having at least two carbon atoms.)   The electrophotographic seamless belt according to claim 1, wherein the electrophotographic seamless belt is an electrophotographic intermediate transfer belt. The R of the bisallylnadiimide represented by the general formula (i) includes at least one selected from divalent hydrocarbon groups represented by the following chemical formulas (ii) to (iv). The seamless belt for electrophotography according to 1 or 2.

  The electrophotography according to any one of claims 1 to 3, wherein the base layer contains, as a main component, a polyimide other than a polyimide obtained by curing the bisallylnadiimide represented by the general formula (i). Seamless belt for.   The polyimide other than the polyimide obtained by curing the bisallylnadiimide represented by the general formula (i) is obtained from a solution containing polyamic acid in an organic solvent. Seamless belt for electrophotography.   6. The surface layer is formed by coating and heating with a carbon black dispersion liquid containing at least carbon black, bisallylnadiimide represented by the general formula (i), and a solvent. The electrophotographic seamless belt according to any one of the above.   The seamless belt for electrophotography according to claim 6, wherein the content of the carbon black in the surface layer is 2 wt% to 20 wt%. In an electrophotographic apparatus for performing primary transfer by sequentially superimposing a plurality of color toner developed images sequentially formed on an image carrier on an intermediate transfer belt, and performing secondary transfer of the primary transfer image collectively to a recording medium ,
An electrophotographic apparatus, wherein the intermediate transfer belt is the electrophotographic seamless belt according to claim 1.

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