JP5470814B2 - Intermediate transfer member and image forming apparatus using the same - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, and an intermediate transfer member used therefor. The present invention relates to an intermediate transfer type image forming apparatus that performs next transfer, and an intermediate transfer member used therefor.

In an electrophotographic image forming apparatus, a seamless belt member is used for various functions and applications in the apparatus. For example, a fixing belt, a transfer belt, a paper conveyance belt, and the like can be given.
In a full-color image forming apparatus, a four-color toner image formed on a photoreceptor (image carrier) is temporarily transferred to an intermediate transfer belt to form a full-color image on the intermediate transfer belt, and then In addition, there is a method of batch transfer to a transfer medium (recording medium) such as paper, and an intermediate transfer belt which is a seamless belt member is used for this.
The demand for intermediate transfer belts has been rapidly increasing as image forming apparatuses such as copying machines have become full color. As the intermediate transfer belt, materials such as thermoplastic resin, thermosetting resin, rubber, and elastomer are used.

  In the intermediate transfer method using the intermediate transfer belt, in order to obtain high speed, a method called a tandem method in which color developing devices for respective colors facing the intermediate transfer belt are arranged in series is mainly used.

  The intermediate transfer belt used in this tandem system is not subject to color misregistration due to deformation during running, requires high strength that can withstand repeated use, and also requires flame retardancy. Resins are preferably used. In particular, a polyimide resin is preferably used in terms of creep deformability and durability.

  Since the intermediate transfer belt made of polyimide resin has high strength and high surface hardness, a high pressure is applied to the toner layer when the toner image is transferred, and the toner is locally aggregated and a part of the image is not transferred. A so-called hollow image may occur. 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. Rough materials such as paper, Japanese paper and kraft paper are increasingly used. Such followability to papers having different surface properties is important. If the followability is poor, uneven unevenness of color and uneven color tone occur. In addition, the intermediate transfer belt in contact with the sheet requires not only the ability to follow the sheet but also wear resistance.

  Furthermore, it is necessary to control the glossiness of the belt surface. If the glossiness is low, a malfunction occurs in the sensor using light reflection in the electrophotographic apparatus. For this reason, the required glossiness should be maintained and not lowered as the number of print outputs increases. When the glossiness of the intermediate transfer belt decreases, the life of the intermediate transfer belt is shortened.

In order to solve these problems, various intermediate transfer belts in which a relatively flexible layer is laminated on a base layer have been proposed.
On the other hand, the intermediate transfer belt is required to have high flame resistance. However, in the intermediate transfer belt in which the relatively flexible layer as described above is laminated on the base layer, the flame retardancy becomes poor. For this reason, a material called a flame retardant is generally added to develop flame retardancy. However, as a side effect thereof, there have been a problem that the glossiness is lowered and the original characteristics of the film are impaired.

  Therefore, in Patent Document 1, an elastic layer is provided on the base layer, and a relationship between the thickness of the elastic layer and the thickness of the base layer is defined, thereby reducing the hollow image and preventing the film from being damaged. . However, when providing an elastic layer thickness that is effective in this technology, the thickness of the base layer also increases, so that a base layer having a high elastic modulus such as polyimide cannot be used. For this reason, there are problems in creep deformation and durability. Moreover, it does not describe the flame retardancy.

  In Patent Document 2, it is proposed to provide environmental stability of volume resistance by defining volume resistance values of the base layer and the surface layer in the lamination, and further defining the water absorption rate of the material of the surface layer. It is not special as a material to be used, and there is no mention of other physical properties.

  In Patent Document 3, a binder layer having a lower bending elastic modulus than that of the base layer and excellent adhesion to the base layer is provided on the base layer, and fine particles are adhered thereon without impairing the flexibility of the binder layer. Proposals have been made that can achieve good transferability and durability and are inexpensive. However, the invention described in Patent Document 3 has a problem that it is difficult to stably control the coating state of the particles although the particle size of the fine particles is regulated. In addition, the flame retardancy is not described, and is easy to wear and inferior in wear resistance.

  Patent Document 4 proposes a structure in which a surface layer made of liquid silicone rubber in which carbon black is dispersed in a base layer is laminated. Polyimide or polyamideimide is preferably used for the base layer, and the surface layer is made of toner release. It is described that the property and elasticity, and excellent surface properties can be obtained. However, since silicone rubber has poor adhesion to polyimide, it is necessary to provide an adhesive layer. Further, since the dispersibility of carbon black is not good, the resistance tends to vary and the production stability is inferior, and further, no flame retardancy is described.

  Patent Document 5 proposes using a cured methacrylic resin or a cured acrylic resin as a main component of the surface layer. However, Patent Document 5 does not describe glossiness control and does not describe flame retardancy.

  Patent Document 6 discloses an intermediate transfer belt in which an elastic layer is provided as an intermediate layer on a polyether sulfone resin base layer, and a surface layer is provided on the intermediate layer to improve followability to paper and wear resistance. Proposed. It is described that the followability is improved by providing the intermediate layer, the uneven unevenness of the unevenness of the paper and the unevenness of the color tone are improved, and at the same time, the wear resistance is obtained by providing the surface layer. However, Patent Document 6 does not describe glossiness control and does not describe flame retardancy.

  Patent Document 7 proposes a structure in which a surface layer formed by curing a thermosetting resin that is cured at 300 ° C. or less and containing a curing agent is laminated on a thermoplastic base layer. Yes. Further, it is described that by providing a layer imparting elasticity as an intermediate layer in addition to such a configuration, it is possible to make contact with a photoconductor or a recording medium with a wide width and to obtain high transfer efficiency. Further, it is described that the scratch resistance of the surface layer can be improved and the decrease in glossiness can be suppressed. However, since a thermoplastic resin is used as the base layer, deformation and change in resistance occur during the thermosetting of the surface layer, and in addition to poor production stability, flame retardancy is not described.

Japanese Patent Laid-Open No. 2001-100545 JP 2001-125388 A JP 2004-354716 A JP 2006-285048 A JP 2007-316622 A JP 2004-310016 A JP 2005-266793 A

  The present invention solves the above-mentioned problems of the prior art, and is excellent in wear resistance, creep resistance, dimensional stability, durability and scratch resistance, and maintains a certain surface gloss while having flame retardancy. In addition, a high transfer rate and transfer performance are exhibited regardless of the surface properties of a recording medium such as an image carrier or paper, and a high-quality image is provided without abnormal images such as voids, density unevenness, and color unevenness. An intermediate transfer belt for an image forming apparatus having a long life and an image forming apparatus using the intermediate transfer belt are provided.

  As a result of intensive studies, the inventors have selected and laminated an epoxy-silicone copolymer in which a flame-retardant compound is dispersed as a surface resin layer to be laminated on a base layer as an intermediate transfer member. As a result, the inventors have found that the above-mentioned problems can be solved, and have completed the present invention.

That is, in order to solve the above problems, the intermediate transfer member and the image forming apparatus according to the present invention specifically have the technical features described in the following (1) to (8).
(1): 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 at least an epoxy-silicone layer on a base layer. An epoxy-silicone layer containing a polymer is laminated, and the epoxy-silicone layer contains a flame retardant compound and is a surface layer, and the flame retardant compound includes melamine sulfate, chlorinated polyethylene, The intermediate transfer member is any one selected from dibromostyrene, magnesium hydroxide, and zinc borate .

  According to the invention described in (1) above, by providing a layer containing an epoxy-silicone copolymer containing a flame retardant compound as a surface layer on the base layer, high flame retardancy is maintained and transfer is performed. Therefore, it is possible to obtain an intermediate transfer member that has good followability to the surface of the image carrier or recording medium that is in contact with each other, and that can perform good transfer regardless of the surface properties of the image carrier or recording medium.

(2): The intermediate transfer member according to (1), wherein the content of the flame retardant compound is 1 to 100 parts by weight with respect to 100 parts by weight of the epoxy-silicone copolymer. .

  According to the invention described in (2) above, an intermediate transfer body that can perform good transfer without impairing the resin strength and physical properties of the epoxy-silicone copolymer can be obtained.

(3) The intermediate transfer member according to (1), wherein the flame retardant compound has a particle size of 10 μm or less.

  According to the invention described in (3) above, it is possible to maintain the glossiness of the epoxy-silicone copolymer at a high value (suppress reduction).

(4) The intermediate transfer member according to (1) above, wherein the flame retardant compound is a nitrogen compound.

(5) The intermediate transfer member according to (1) above, wherein the flame retardant compound is a chlorine compound.

  According to the inventions described in the above (4) and (5), an intermediate transfer body having high flame retardancy and high glossiness can be obtained with a smaller content of the flame retardant compound.

(6) The intermediate transfer member according to (1) above, which is a seamless belt.

  According to the invention described in (6) above, an intermediate transfer member capable of efficiently transferring an image onto paper can be obtained.

(7): an image bearing member on which a latent image is formed and capable of bearing a toner image, a developing unit that develops the latent image formed on the image bearing member with toner, and a toner image developed by the developing unit And an intermediate transfer member on which the toner image carried on the intermediate transfer member is secondarily transferred to a recording medium. The intermediate transfer member is described in (1) above. The image forming apparatus is an intermediate transfer member.

  According to the invention described in (7) above, since the intermediate transfer member is used, an image forming apparatus capable of forming a high-quality image without generating an abnormal image over a long period of time can be provided. The intermediate transfer member in the present invention is not limited to a tandem type image forming apparatus. In addition, for example, a transfer drum system and a transfer roll system are also applicable.

(8): The image forming apparatus is a full-color image forming apparatus, in which a plurality of image carriers corresponding to each color are arranged in series, and each of the plurality of latent image carriers has a developing unit corresponding to each color. The image forming apparatus as described in (7) above.

  According to the invention described in (8) above, it is possible to provide an image forming apparatus suitable for full color image formation adapted to higher speed while maintaining quality.

According to the present invention, high flame retardancy is maintained, and the followability to the surface of the image carrier or recording medium that is in contact with the transfer portion is good, regardless of the surface properties of the image carrier or recording medium. An intermediate transfer body on which transfer is performed can be provided.
Further, according to the present invention, it is possible to provide an image forming apparatus capable of forming a high-quality image without generating an abnormal image over a long period of time.

<Intermediate transfer member>
The intermediate transfer member according to the present invention is an intermediate transfer member onto which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred, and the intermediate transfer member includes at least a base layer An epoxy-silicone layer containing an epoxy-silicone copolymer is laminated on the epoxy-silicone layer, and the epoxy-silicone layer contains a flame retardant compound.

Next, the intermediate transfer member according to the present invention will be described in more detail.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

[Base layer]
Resins used for the base layer include polyester, polyethylene, polypropylene, polyalkylene terephthalate, polyamide, polyimide, polycarbonate, thermoplastic resins such as ABS, PVdF, ETFE and other fluorine resins, ester-based, olefin-based, amide-based, and diene-based resins. , Silicone-based thermoplastic elastomers, epoxy-based, phenol-based, urethane-based, imide-based, silicone-based thermosetting resins, etc., acrylonitrile rubber, chloroprene rubber, chlorosulfonated ethylene rubber, ethylene propylene diene rubber, silicone Rubbers such as rubber, fluororubber and epichlorohydrin rubber are used.
Among these, as the base layer, a fluorine resin or an imide resin is preferably used in terms of excellent mechanical strength durability without deformation in the apparatus and in terms of flame retardancy. More preferably, polyimide or polyamideimide resin is applied.

In the present invention, an epoxy-silicone layer described later is laminated on the base layer.
Furthermore, in the present invention, a surface layer may be laminated on the epoxy-silicone layer. The above-mentioned general resins can be applied as the surface layer, but fluorine-based and silicone-based resins are preferable from the viewpoints of toner releasability and wear resistance.

First, the polyimide resin used suitably for a base layer and a surface layer is demonstrated.
In the case of an intermediate transfer belt (intermediate transfer member) made of a polyimide resin, a belt formed by applying a solution made of a polyimide precursor using an organic polar solvent as a coating solution and applying the coating solution to a mold is preferably used.
The polyimide produced | generated by the heat processing (imidation) of the polyimide precursor which is a component of a coating liquid is demonstrated in detail.

<Polyimide>
The polyimide used in the present invention is first obtained via a polyamic acid (polyimide precursor) by reaction of a generally known aromatic polycarboxylic acid anhydride or derivative thereof with an aromatic diamine.
That is, polyimide is insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, a polyimide precursor that is soluble in an organic solvent from an acid anhydride and an aromatic diamine ( Polyamic acid or polyamic acid) is synthesized, and at this stage, molding is performed by various methods, and then the polyamic acid is subjected to dehydration reaction by heating or a chemical method to be cyclized (imidized) to obtain polyimide. The outline of the reaction is shown in the following chemical reaction formula.

(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 include, for example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic 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-dicarboxyphenyl) methane dianhydride, 2,2-bis ( 3, 4 Dicarboxylphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetra Carboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic acid A dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, 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 to be reacted with the polycarboxylic 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-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) ) Sulfone, bis (4-aminophenyl) Hong, 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] 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-amino) Phenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ke 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-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bi [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 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 for producing a polyimide precursor, first, one or a plurality of diamines are dissolved in the above organic solvent or diffused in a slurry state in an inert gas atmosphere such as argon or nitrogen. When at least one aromatic polycarboxylic 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 generates heat. A ring-opening polyaddition reaction occurs, and the viscosity of the solution rapidly increases, 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. 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 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.

In the present invention, it is possible to use a polyimide precursor solution (polyamic acid solution) synthesized as described above, but in a state where the polyamic acid composition is simply dissolved in an organic solvent, What is marketed as what is called 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.

  A filler described later is mixed and dispersed in the synthesized or obtained polyamic acid solution, and a siloxane compound (polydimethylsiloxane or alkylene oxide-modified polymethylsiloxane) is further added and mixed to prepare a coating solution. 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.

That is, 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 heat treatment at 200 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 (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 the method is more complicated and costly than the method of heating.
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 resonance spectroscopy calculated from an integration ratio of 1H attributed to an amide group in the vicinity of 9 to 11 ppm and 1H attributed to an aromatic ring in the vicinity of 6 to 9 ppm. Various methods are used such as a method (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. Outer 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), Is done.

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 imidation ratio can be evaluated using the following absorbance ratios (1) to (4).
(1) Absorbance ratio between 725 cm ⁻¹ (immobilization band of imide ring C═O group), which is one of characteristic absorptions of imide, and 1,015 cm ⁻¹ of characteristic absorption of benzene rings.
(2) Absorbance ratio between 1,380 cm ⁻¹ (inflection vibration band of imide ring C—N group), which is one of characteristic absorptions of imide, and 1,500 cm ⁻¹ of characteristic absorption of benzene rings.
(3) Absorbance ratio between 1,720 cm ⁻¹ (immobilization vibration band of imide ring C═O group) which is one of characteristic absorptions of imide and 1,500 cm ⁻¹ of characteristic absorption of benzene ring.
(4) 1,720 cm ⁻¹ which is one of characteristic absorptions of imide and 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and C—N stretching vibration) Absorbance ratio.
Moreover, if it is confirmed that the multiple absorption band derived from the amide group over 3000 to 3300 cm ⁻¹ disappears, the reliability of imidization completion is further increased.

In the present invention, not only the polyimide precursor solution as described above but also a so-called solvent-soluble polyimide that has been imidized in advance and is soluble in an organic polar solvent can be used.
Examples of this include Rika Coat (New Nippon Rika) and block copolymerized polyimide (PI Giken).

  In addition, the coating solution may contain not only the polyimide but also other resin components as necessary. Moreover, you may use various additives, such as a leveling agent, a lubricant, antioxidant, a catalyst.

Next, the filler contained as a component of the coating liquid will be described. As the filler, general organic and inorganic materials can be used.
When used as an intermediate transfer belt, a resistance adjusting agent having a resistance adjusting function is used as a filler. The resistance adjuster is indispensable for adjusting the intermediate transfer belt to a predetermined resistance value.
As the resistance control agent, carbon black, graphite, or metal such as copper, tin, aluminum, indium, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, Examples thereof include metal oxide fine powders such as indium oxide doped with tin. In addition, as an ion conductive resistance control agent, tetraalkylammonium salt, trialkylbenzyl, ammonium salt, alkylsulfonate, alkylbenzenesulfonate, alkylsulfate, glycerol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine Polyoxyethylene fatty alcohol ester, alkyl betaine, lithium perchlorate and the like may be used. Further, polyether amide, polyether ester amide, polypyrrole, polythiophene, polyaniline, or the like which is a conductive polymer may be used. In addition, the resistance control agent used for this invention is not limited to these exemplary compounds.

In the present invention, carbon black is preferably used among the resistance control 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 dispersion aid as needed. Furthermore, the surface functional group of carbon black and the surface treatment may be performed by reacting an organic compound having reactivity with the functional group.

Next, a method for producing an intermediate transfer belt using the coating liquid containing the polyimide precursor will be described.
A step of dispersing a resistance adjuster as necessary, a step of applying and casting a coating solution produced by the step on a support (molding mold), and a coating in a coating applied and cast on the support Manufactured by removing the solvent by heating, heating the mixture to promote imidation of the precursor contained in the coating film, and releasing the formed thin film from the support to form an intermediate transfer belt .

In the step of dispersing the resistance adjusting agent, there are a method of dispersing and mixing the resistance control agent directly in the polyimide precursor solution or a method of dispersing the resistance control agent in a solvent in advance and then mixing with the polyimide precursor solution.
Here, a method of dispersing carbon black as a resistance control agent will be described as an example. Note that this is an example and the present invention 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 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. As a method for forming a polyimide intermediate transfer belt, a centrifugal molding method is often used. However, in order to form a film on the inner surface of a support, when a layer is laminated on the surface, after film formation, the mold is once removed and separated. Therefore, it is necessary to form the surface layer by another coating method and the process becomes complicated. Therefore, in the case of the present invention, roll coating, dispenser coating, ring coating, and die coating are preferable as the construction method that can be applied to the outer surface of the support and sequentially laminated with the base layer and the surface layer.
After applying a coating solution made of polyamic acid to a predetermined thickness on the outer surface of a metal cylindrical support that has been previously coated with a release agent by the above method, the coating film is dried with a hot air dryer, IH heater, far-infrared heater or the like. . 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. The base layer and the surface layer are not necessarily formed by the same method.

[Epoxy-silicone layer]
Next, the epoxy-silicone layer will be described.
The epoxy-silicone layer in the present invention includes an epoxy-silicone copolymer and is laminated on the base layer. The epoxy-silicone layer contains a flame retardant compound.
This epoxy-silicone layer may be a single layer (outermost surface layer), constitutes a part of a single layer intermediate layer or a plurality of intermediate layers, and further has an outermost surface layer. Also good.

<Epoxy-silicone copolymer>
The epoxy-silicone layer is preferably an epoxy-silicone copolymer.
Since the epoxy-silicone copolymer has an appropriate flexibility, it does not crack even when the intermediate transfer belt is bent. Further, it can sufficiently follow the surface of the image carrier or the recording medium.
Furthermore, since it is liquid, it can be produced by the same method as that for the base layer, which is suitable for continuous production. Further, the viscosity can be adjusted with a solvent or the like as necessary, and various additive materials can be easily blended.

The epoxy-silicone copolymer is formed by crosslinking and curing a block copolymer of an epoxy part and a silicone part.
The block copolymer is obtained by alternately copolymerizing siloxane units having a reactive group that reacts with an epoxy group of a general epoxy site such as bisphenol A type di-glycidyl ether and bisphenol F type di-glycidyl ether. It is an epoxy group.

  By introducing the silicone site to be introduced, the layer having the flexibility described above can be obtained. Although the flexibility increases as the amount of silicone increases, the amount of silicone to be introduced is preferably 40 to 60 wt%. If it is 40 wt% or less, it is hard and inferior in flexibility, and if it is 60 wt% or more, the film strength is low and it cannot withstand actual use durability.

  This copolymer is polymerized by thermosetting using a general-purpose catalyst for epoxy resin and a curing agent. As heating temperature, the heating of about 120 to 250 degreeC is required. For this reason, when a general thermoplastic resin is used, it is necessary to select one having high heat resistance because thermal deformation (shrinkage) may occur when the epoxy-silicone layer is heated. When such a resin is used, it is necessary to perform melt molding at a high temperature, which is not preferable for production. Therefore, polyimide is preferably used for the base layer in the present invention.

  As the curing agent for the epoxy-silicone copolymer, an acid anhydride compound, an amine compound, or a phenol compound is preferably used.

  Examples of the acid anhydride compound include tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydroanhydride. Phthalic acid, methylcyclohexene tetracarboxylic dianhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, ethylene glycose bisanhydrotrimellite, glycerin bis (anhydrotrimetic) Examples include monoacetate, dodecenyl succinic anhydride, aliphatic dibasic acid polyanhydride, and chlorendic anhydride.

  Examples of amine compounds include diethylenetriamine, triethylenetetramine, diethylaminopropylamine, N-aminoethylpiperazine, benzyldimethylamine, tris (dimethylaminomethyl) phenol, metaphenylenediamine, diaminophenylmethane, diaminodiphenylsulfone, polyamide resin, Examples include imidazole compounds. In particular, imidazole compounds are preferably used. For example, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl. Imidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-benzyl-2-methyl Imidazole, 1-benzyl-2-phenylimidazole, 2,4-diamino-6- (2′-methylimidazolyl- (1 ′)-ethyl-s-triazine, 2,4-diamino-6- (2′-un) Decylimidazolyl- (1 ′)-ethyl-s-triazine 2,4-diamino-6- (2'-ethylimidazolyl- (1 ')-ethyl-s-triazine, 2,4-diamino-6- (2'-methylimidazolyl- (1')-ethyl-s- Examples include triazine isocyanuric acid adducts, 2-methylimidazole isocyanuric acid adducts, and imidazole silanes.

  As the phenol compound, a novolac type phenol resin or a resol type phenol resin is preferably used. In addition, phenol-modified polyimide can also be used. These curing agents can be used not only alone but also in combination.

Among these curing agents, liquid ones are easily used because they can be easily mixed into liquid resins. It is also possible to add a solid material by dissolving it in a solvent and mixing it.
Moreover, the compounding quantity mix | blends the quantity calculated so that the epoxy equivalent of a epoxy-silicone copolymer and a reactive group equivalent may correspond.

Various additives can be blended in this resin as necessary, as in the base layer.
In particular, the formulation of the resistance adjuster will be described. As the resistance adjusting agent, the same ones as described above can be applied. In particular, carbon black is preferably used. Epoxy-silicone copolymers have good dispersibility with respect to carbon black and are easily obtained with small variations in resistance.

  There are two methods for blending the resistance adjuster and the block polymer into the resin: a method of directly mixing and a method of mixing after dissolving or dispersing in a solvent. It is preferable to mix by the method.

  Next, the obtained coating solution is applied on the base layer made of polyimide so as to have a predetermined film thickness by using a method preferably selected from the same method as described above. The final film thickness is preferably about 50 to 300 μm in order to exhibit preferable transfer performance. If the film is too thin, the followability to the surface properties of the photoreceptor and the transfer medium is not sufficient, and if it is too thick, the film tends to crack during driving at the curvature portion of the tension roller of the belt.

  After application, it is cured by heating in a dryer. The heating temperature is set to an appropriate temperature depending on the type of the crosslinking agent to be used, but it is preferable to cure in a temperature range of about 120 ° C to 250 ° C. After drying, it is cooled and removed from the mold to obtain a seamless belt.

  In the above description, the base layer and the surface layer have a two-layer structure. However, the present invention is not necessarily limited to this structure, and a plurality of layers may be stacked as necessary. Further, in the above description, the seamless belt has been described. However, the present invention is not limited to this, and may have a shape in which end belts are joined together or may have a shape other than the belt shape. The shape of the transfer body can be obtained.

<Flame retardant compound>
As the flame retardant compound used in the present invention, both an organic flame retardant and an inorganic flame retardant can be used. Examples of organic flame retardants include halogen compounds, phosphorus compounds, melamine compounds, boron compounds, and silicone compounds, and inorganic flame retardants include metals, metal oxides, metal hydroxides, and metals. And carbonate compounds.

  Specific examples of the halogen flame retardant include, for example, pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromocyclooctane, tetrabromobisphenol A, tetrabromophenyl allyl ether, tribromoneopentyl alcohol, hexabromocyclododecane. , Hexabromobenzene, bis (pentabromophenyl) ethane, 1,2-bis (2,4,6-tribromophenoxy) ethane, 2,4,6-tris (2,4,6-tribromophenoxy)- 1,3,5-triazine, decabromodiphenyl oxide, octabromodiphenyl oxide, ethylene bis (pentabromophenyl), poly (pentabromobenzyl polyacrylate), ethylene bis (tetrabromophthal Bromides such as imide), tetrabromophthalic anhydride, brominated (alkyl) phenol, brominated polystyrene, brominated polyethylene, octabromotrimethylphenylindane, pentabromobenzyl acrylate, polydibromophenylene oxide, bis (tribromophenoxyethane) , Chlorinated paraffin, chlorinated polyethylene, chlorinated naphthalene, chlorinated polyphenyl, perchloropentacyclodecane, tetrachlorophthalic anhydride, chloroendic anhydride, hexachloroethane, hexachlorocyclohexane, tetrachlorophthalic anhydride, penta Chlorine such as chlorobenzene can be mentioned.

  Specific examples of the phosphorus flame retardant include, for example, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, diphenyl octyl phosphate, triallyl phosphate, tricresyl phosphate, cresyl Diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, triallyl phosphate, tri (hydroxyphenyl) phosphate, diethyl bis (hydroxyethyl) aminomethylphosphonate, tris (3-hydroxypropyl) phosphine oxide, dibutylhydroxymethylphosphonate, di (butoxy) ) Phosphinyl propylamide, dimethylmethyl phosphonate, guanidine phosphate, trisdichloro B pills phosphate, tris β- chloropropyl phosphate, polybrominated styrene, ammonium polyphosphate, polyphosphoric acid amide, such as red phosphorus and the like.

  Specific examples of nitrogen-based flame retardants include, for example, ammonium sulfate, melamine, melamine sulfate, acetoguanamine, benzoguanamine, melon, melam, succinoguanamine, ethylene dimelamine, guanylmelamine sulfate, melem sulfate, melam sulfate, mono (hydroxymethyl) Examples include melamine, di (hydroxymethyl) melamine, tri (hydroxymethyl) melamine, melamine cyanurate, cyanurate, 2-amide-4,6-diamino-1,3,5-triazine, melamine phosphate and the like.

  Specific examples of the boron flame retardant include boric acid, borax, zinc borate, zinc metaborate, barium metaborate, and the like.

  Any silicone-based flame retardant can be used without particular limitation as long as it is an organic compound containing a silicon atom. Examples thereof include silicone oil, silicone resin, and silsesquioxane.

  Specific examples of the metal include aluminum, iron, zinc, nickel, copper, titanium molybdenum, manganese, cobalt, bismuth, chromium, tungsten, and tin.

  Specific examples of the metal oxide include, for example, antimony trioxide, antimony tetraoxide, antimony pentoxide, cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxide, tungsten iron oxide, titanium oxide, manganese oxide, and zirconium oxide. Zinc molybdate, molybdenum trioxide, zinc stannate, tin oxide, aluminum oxide, zinc oxide, molybdenum oxide and the like.

  Specific examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, zirconium hydroxide, dolomite, hydrotalcite, and zinc hydroxystannate.

  Examples of the metal carbonate compound include cobalt carbonate, titanium carbonate, zinc carbonate, magnesium carbonate, basic magnesium carbonate, aluminum calcium carbonate, barium carbonate, and iron carbonate.

  These flame retardant compounds may be used alone or in combination of two or more as required.

Among the above flame retardant compounds, nitrogen flame retardants (nitrogen compounds) or chlorine flame retardants (chlorine compounds) exhibit high flame retardancy in combination with epoxy-silicone copolymers. Melamine, ammonium sulfate, melamine cyanurate and chlorinated polyethylene are preferred, and melamine sulfate, melamine cyanurate and chlorinated polyethylene are more preferred.
Melamine sulfate, ammonium sulfate, melamine cyanurate, and chlorinated polyethylene can be suitably used in that they are easy to make particles finer, flame-retardant with a small blending amount, and can have a high gloss value.
In this case, the dispersion solvent is not particularly limited, but alcohols and ketones are preferable from the viewpoint of compatibility with the epoxy-silicone copolymer. Further, in order to efficiently reduce the size of the particles, a dispersant such as a silicone surfactant or a fluorine surfactant may be used as appropriate.

  In blending the flame retardant compound into the resin, there are a method of directly mixing and a method of mixing after dissolving or dispersing in a solvent. If the primary particle size of the flame retardant compound is large, the effect of the present invention is obtained. Since it is not sufficiently exerted, it is necessary to pulverize or disperse to a predetermined particle size. In the present invention, the particle size of the flame retardant compound is preferably 10 μm or less, more preferably 3 μm or less.

  In the pulverizing step, the method is not particularly limited, and examples thereof include a method of mechanically pulverizing using a large mixer or the like, or dispersing with a commonly used disperser such as a ball mill, a roll mill, or a sand mill. Among these, high-speed sand mills are preferable. For example, when using a super mill, sand grinder, bead mill, agitator mill, glen mill, dyno mill, pearl mill, cobol mill (all of which are trade names), the particle size can be reduced in a shorter time. it can.

  Here, in order to measure the particle diameter of the flame-retardant compound that has been atomized, a sample diluted with a dispersion solvent can be measured with a particle size analyzer (for example, Microtrack UPA manufactured by Nikkiso Co., Ltd.).

  The amount of the flame retardant compound finely divided can be appropriately selected depending on the required flame retardancy, but is preferably 1 to 100 parts by weight, more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the resin. Part. If the blending amount is more than 100 parts, the glossiness of the film is lost and the actual use durability cannot be endured. On the other hand, if the blending amount is less than 1 part, it is not preferable because sufficient flame retardancy cannot be exhibited.

  In the present invention, the flame retardancy of the flame retardant compound-blended film can be evaluated based on the UL94-VTM test (thin material vertical combustion test).

<Image forming apparatus>
An image forming apparatus according to the present invention includes an image carrier on which a latent image is formed and can carry a toner image, a developing unit that develops the latent image formed on the image carrier with toner, and the developing unit. An intermediate transfer member to which the developed toner image is primarily transferred; and transfer means for secondary transfer of the toner image carried on the intermediate transfer member to a recording medium. It is characterized by being an intermediate transfer member.
The image forming apparatus according to the present invention is a full-color image forming apparatus, in which a plurality of image carriers corresponding to each color are arranged in series, and each of the plurality of latent image carriers is a developing unit corresponding to each color. It is characterized by having.

Next, an image forming apparatus according to the present invention and a seamless belt used in a belt constituting unit provided in the image forming apparatus will be described in detail below with reference to schematic diagrams of relevant parts. 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 the main part of an electrophotographic apparatus equipped with a belt component and the like. 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), a secondary transfer bias roller (605) as a secondary transfer charge applying means of a secondary transfer unit (600) as a transfer means, and a belt cleaning as an intermediate transfer body cleaning means. A blade (504), a lubricant application brush (505), which is a lubricant application member of the lubricant application means, and the like are arranged 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.

  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 serving as the belt component is usually a semiconductor or an insulator, and the seamless belt of the present invention having a single-layer or multilayer structure is used, thereby improving durability and excellent image formation. realizable. Further, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose toner images formed on the photosensitive drum (200) as an image carrier.

  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 as a recording medium between the intermediate transfer belt (501) of the portion stretched around the secondary transfer counter roller (510). A transfer bias of 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 a counterclockwise direction indicated by an arrow by a driving motor (not shown), and the photosensitive drum (200) is rotated on the photosensitive drum (200). In addition, 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. 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 using the laser light L 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. The negatively charged Bk toner on the developing roller of the Bk developing device (231K) as the developing means comes into contact with this Bk electrostatic latent image, so that the portion where the charge on the photosensitive drum (200) remains is left. The toner does not adhere and the toner is attracted to the portion without charge, 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 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 Y image forming process after the Bk image forming process, and reading of Y image data by a color scanner starts at a predetermined timing. A Y 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 (T) electrostatic latent image reaches, the revolver developing unit (230) is rotated, and Y development is performed. The machine (231Y) is set at the development position, and the Y electrostatic latent image is developed with Y toner. Thereafter, the development of the Y electrostatic latent image area is continued, but when the rear end of the Y electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the previous Bk developing machine (231K). Then, the next C developing machine (231C) is moved to the developing position. This is also completed before the leading edge of the next C electrostatic latent image reaches the developing position. Note that the C and M image forming steps are the same as the Bk and Y steps described above because the color image data reading, electrostatic latent image forming, and developing operations are the same as those described above.

The Bk, Y, C, and M 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 the registration between 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 which is the intermediate transfer member 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).

  A toner seal member (503) that contacts and separates from the belt outer peripheral surface of the intermediate transfer belt (501) is provided on the upstream side of the belt cleaning blade (504) in the moving direction of the intermediate transfer belt (501). Yes. The toner seal member (503) receives the falling toner dropped from the belt cleaning blade (504) during cleaning of the residual toner, and the falling toner is scattered on the transfer path of the transfer paper (P). It is preventing. The toner seal member (503) 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 copy, the operation of the color scanner and the image formation on the photosensitive drum (200) are performed at a predetermined timing following the image formation process for the fourth color (M) of the first sheet. 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 the 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 the above-described embodiment, the copying machine including only one photosensitive drum 1 has been described. However, the present invention may include a plurality of photosensitive drums (image carriers) as shown in FIG. The present invention can also be applied to an image forming apparatus arranged along (intermediate transfer member).
FIG. 2 shows four drums including four photosensitive drums (21BK), (21Y), (21M), and (21C) for forming toner images of four different colors (black, yellow, magenta, and cyan). 1 shows an example of the configuration of a type digital color printer.

In FIG. 2, the printer main body (10) includes an image writing unit (12), an image forming unit (13), and a paper feeding unit (14) for forming a color image 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. There are four writing optical paths, and image carriers (photoconductors) (21BK), (21M), (21Y), and (21C) provided for each color of the image forming unit (13) according to the respective color signals. Perform image writing.

  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) as primary developing means, primary transfer bias rollers (23BK), (23M), (23Y), (23C) as primary transfer means , A cleaning device (not shown), a photosensitive member static elimination device (not shown), and the like 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.

  The seamless belt according to the present invention can be preferably 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 ( The present invention can also be applied to a transfer / conveying belt type image forming apparatus equipped with a transfer / conveying belt instead of 22). 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. For the flame retardancy test, in order to clarify the effect of the flame retardant film in each Example and Comparative Example, a test piece having a length of 200 mm, a width of 50 mm, and a thickness of 0.240 mm was cut out as a test film. Five pieces were made for the flame retardant test. About other conditions and evaluation, it carried out based on UL94-VTM test (thin material vertical combustion test).
Of Examples 1 to 12 shown below, Examples 4 to 5 and 11 are test examples as reference examples not belonging to the scope of the present invention.

[Example 1]
[Preparation of coating solution for base layer]
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.

<Dispersion constituent material for base layer>
Polyimide solution U-Varnish A (Ube Industries, Ltd .; solid content 18%) 2 parts by weight Carbon black Special black 4 (Degussa) 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical Corporation) 88 parts by weight

  Using the above dispersion, the following constituent materials were mixed, mixed and defoamed with a centrifugal stirring deaerator to obtain a coating solution.

<Coating liquid composition material for base layer>
Carbon black dispersion 50 parts by weight Polyimide solution U-varnish A (Ube Industries, Ltd .; solid content 18 wt%) 50 parts by weight Polyether-modified silicone FZ2105 (Toray Dow Corning) 0.01 parts by weight

[Production of seamless belt]
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 coating is performed while rotating the cylinder at 50 rpm (times / minute). The liquid was uniformly cast on the outer surface of the cylinder using a dispenser. The coating amount was such that the final film thickness was 60 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.

[Preparation of coating solution A for surface layer]
First, the following constituent materials were mixed and dispersed using a zirconia bead having a diameter of 1 mm for 6 hours with a bead mill disperser to prepare a surface layer carbon dispersion A.

<Structure material of carbon dispersion A for surface layer>
Epoxy-silicone copolymers;
ALBIFLEX 348 (silicone 60 wt% Nanoresins) 1 part by weight Carbon black Special black 4 (Degussa) 10 parts by weight N-methyl-2-pyrrolidone (Mitsubishi Chemical) 89 parts by weight

[Preparation of Flame Retardant Dispersion A for Surface Layer (Epoxy-Silicone Layer)]
Subsequently, each constituent material shown below was mixed and dispersed using a zirconia bead of φ0.3 mm for 5 hours in a sand mill disperser to prepare flame retardant dispersion liquid A.

<Flame retardant dispersion liquid A for the surface layer>
Melamine sulfate; Apinon-901 (Sakai Chemical Industry Co., Ltd.) 15 parts by weight Epoxy-silicone copolymer;
ALBIFLEX 348 (Silicone 60wt% Nanoresins) 1 part by weight 1-butanol 82 parts by weight

At this time, the volume average particle diameter of melamine sulfate was 0.322 μm.
Next, using the carbon dispersion A for surface layer and the flame retardant dispersion A for surface layer, mixing is performed so that the weight ratio of the solids of the respective constituent materials is as follows. , Mixed and degassed to obtain surface layer coating solution A.

<Material composition of coating liquid A for surface layer>
35.4 parts by weight of the above carbon black dispersion A for surface layer
ALBIFLEX 348 (Silicone 60 wt% Nanoresins) 26 parts by weight methyltetrahydrophthalic anhydride;
HN-2000 (Hitachi Kasei Kogyo Co., Ltd.) 4.2 parts by weight The above surface layer flame retardant dispersion A 34.4 parts by weight (20 parts by solid content with respect to resin)

[Preparation of surface layer A on the base layer]
On the polyimide base layer produced previously, the said surface layer coating liquid A was similarly cast | casted and apply | coated to the outer surface using the dispenser. The coating amount was such that the final film thickness was 240 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 120 ° C. at a temperature rising rate of 2 ° C./min, and heated for 30 minutes. Then, it heated up to 250 degreeC with the temperature increase rate of 2 degree-C / min, and heat-processed for 120 minutes. After stopping the heating, it was gradually cooled to room temperature, sufficiently cooled and demolded to obtain a seamless belt A.

[Comparative Example 1]
A seamless belt B was obtained in the same manner as in Example 1, except that the surface layer flame retardant dispersion A was not used.

[Example 2]
The same method as in Example 1 except that the surface layer flame retardant dispersion A prepared in Example 1 was used, the amount added to the surface layer coating liquid A was changed, and 120 parts of the resin was added to the resin. A seamless belt C was obtained.

[Example 3]
Dispersion was carried out in the same manner except that the dispersion time of the surface layer flame retardant dispersion A in Example 1 was changed to 30 minutes, thereby preparing a surface layer flame retardant dispersion D. The volume average particle diameter of melamine sulfate at this time was 23.5 μm. Thereafter, a seamless belt D was obtained in the same manner as in Example 1.

[Example 4]
Example 1 except that melamine sulfate in the flame retardant dispersion A for surface layer of Example 1 was changed to melamine cyanurate (STABIACE MC-5F; manufactured by Sakai Chemical Co., Ltd.) and the solvent was changed from 1-butanol to methyl isobutyl ketone. Dispersion was carried out in the same manner to prepare a surface layer flame retardant dispersion E. The volume average particle size of melamine cyanurate at this time was 0.214 μm. Next, mixing was carried out at the same mixing ratio as in Example 1 to prepare a surface layer coating solution E. Thereafter, a seamless belt E was obtained in the same manner as in Example 1.

[Example 5]
Dispersion was carried out in the same manner except that the dispersion time of the surface layer flame retardant dispersion liquid D of Example 4 was changed to 30 minutes, thereby preparing a surface layer flame retardant dispersion liquid F. The volume average particle diameter of melamine cyanurate at this time was 10.9 μm. Thereafter, a seamless belt F was obtained in the same manner as in Example 1.

[Example 6]
The same as in Example 1 except that the melamine sulfate in the flame retardant dispersion A for surface layer of Example 1 was changed to chlorinated polyethylene (Elaslene 401; manufactured by Showa Denko KK), and the solvent was changed from 1-butanol to methyl isobutyl ketone. Dispersion was carried out by the method to prepare a surface layer flame retardant dispersion liquid G. The volume average particle diameter of the chlorinated polyethylene at this time was 0.537 μm. Next, mixing was carried out at the same mixing ratio as in Example 1 to prepare a surface layer coating solution G. Thereafter, a seamless belt G was obtained in the same manner as in Example 1.

[Example 7]
The same method as in Example 1 except that the surface layer flame retardant dispersion I prepared in Example 6 was used, the amount added to the surface layer coating liquid G was changed, and 120 parts of the resin was added to the resin. The seamless belt H was obtained.

[Example 8]
A surface layer flame retardant dispersion I was prepared in the same manner as in Example 6 except that the dispersion time of the surface layer flame retardant dispersion G was changed to 30 minutes. The volume average particle size of the chlorinated polyethylene at this time was 27.9 μm. Thereafter, a seamless belt I was obtained in the same manner as in Example 1.

[Example 9]
Dispersion was performed in the same manner as in Example 1, except that melamine sulfate in the flame retardant dispersion A for surface layer of Example 1 was changed to polydibromostyrene (Great Lakes pdbs-80 (manufactured by Chemtura Japan)). A surface layer flame retardant dispersion J was prepared. At this time, the volume average particle size of Great Lakes pdbs-80 was 0.298 μm. Next, the mixture was mixed at the same mixing ratio as in Example 1 to prepare a surface layer coating solution J. Thereafter, a seamless belt J was obtained in the same manner as in Example 1.

[Example 10]
Dispersion was performed in the same manner as in Example 1 except that melamine sulfate in the flame retardant dispersion liquid A for Example 1 was changed to magnesium hydroxide (MGZ-5; manufactured by Sakai Chemical Industry Co., Ltd.). A fuel dispersion K was prepared. The volume average particle diameter of MGZ-5 at this time was 0.134 μm. Next, the mixture was mixed at the same mixing ratio as in Example 1 to prepare a surface layer coating solution K. Thereafter, a seamless belt K was obtained in the same manner as in Example 1.

[Example 11]
Example 1 except that the melamine sulfate in the flame retardant dispersion A for surface layer of Example 1 was changed to a condensed phosphate ester (Adekastab FP-700; manufactured by Adeka) and the solvent was changed from 1-butanol to methyl isobutyl ketone. Dispersion was carried out in the same manner to prepare a surface layer flame retardant dispersion liquid L. The volume average particle diameter of ADK STAB FP-700 at this time was 0.456 μm. Next, they were mixed at the same mixing ratio as in Example 1 to prepare a surface layer coating solution L. Thereafter, a seamless belt L was obtained in the same manner as in Example 1.

[Example 12]
Example except that melamine sulfate in the flame retardant dispersion A for surface layer of Example 1 was changed to zinc borate (Alkanex FRC-500; manufactured by Mizusawa Chemical Co., Ltd.) and the solvent was changed from 1-butanol to 1-octanol. Dispersion was carried out in the same manner as in No. 1 to prepare a surface layer flame retardant dispersion M. The volume average particle size of Alkanex FRC-500 at this time was 3.24 μm. Next, mixing was carried out at the same mixing ratio as in Example 1 to prepare a surface layer coating solution M. Thereafter, a seamless belt M was obtained in the same manner as in Example 1.

  Table 1 shows the results of UL94-VTM tests of the seamless belt samples (A to M) of Examples 1 to 12 and Comparative Example 1.

  Further, the seamless belt samples (A to M) of Examples 1 to 12 and Comparative Example 1 were equipped as the intermediate transfer belt shown in FIG. 2, and a blue solid image composed of two colors of cyan and magenta was printed. As the paper, ripple paper FC Japanese paper (Ricoh Co., Ltd.) was used. This paper is a paper with a pattern in Japanese paper style and a smooth surface with a surface quality of 5. A blue solid image printed on the paper was observed to evaluate the color uniformity.

Thereafter, each seamless belt was taken out, the 20 ° glossiness of the surface was measured, and it 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. The paper used was TYPE 6200 (manufactured by Ricoh Co., Ltd.). A gloss meter PG-1 (Nippon Denshoku Industries Co., Ltd.) was used for the gloss measurement. The measurement area is 10.0 × 10.6 mm. The results are shown in Table 2.
The evaluation index for solid image observation is that the solid density is uniform, the solid density is slightly thin in the concave portions, and the concave portions are completely removed.

Based on the results shown in Table 2, the intermediate transfer belts of Examples 1 to 12 maintain high gloss even after printing 10,000 sheets, with the required belt surface 20 ° gloss of 60 to 200. I understand that. The intermediate transfer belt of Comparative Example 1 has a high glossiness at the initial stage, but the glossiness is greatly lowered after printing and is inferior in durability. Further, from Table 1, even with the same flame retardant material, the greater the number of blended parts, the higher the flame retardancy, but the lower the glossiness and the worse the transfer to the recesses. Further, even with the same number of blending parts, the smaller the particle size, the better the flame retardancy and the higher the gloss.
In this way, by adjusting the particle size and the number of blended parts of the flame retardant compound, while maintaining flame retardancy and maintaining high glossiness, it depends on the surface properties of the recording medium such as an image carrier or paper. Therefore, high transfer performance is exhibited, and there is no abnormal image such as voids, density unevenness, and color unevenness, and a high-quality full-color image can be realized over a long period of time.

FIG. 2 is a schematic view of a main part for explaining the configuration of an embodiment of an image forming apparatus according to the present invention and an intermediate transfer member used therefor. FIG. 5 is a schematic diagram of a main part for explaining the configuration of another embodiment of the image forming apparatus according to the present invention and an intermediate transfer member used therefor.

Explanation of symbols

(Figure 1)
P Transfer paper 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photoconductor cleaning device 202 Static elimination lamp 203 Charging charger 204 Potential sensor 205 Toner image density sensor 210 Belt conveyor 230 Revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C Developer 231M M Developer 270 Fixing device 271, 272 Fixing roller 500 Intermediate transfer unit 501 Intermediate transfer belt 503 Toner seal member 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 detection roller 513 Toner image 514 Optical sensor 6 00 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 (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 rollers 20BK, 20M, 20Y, 20C Developing devices 21BK, 21M, 21Y, 21C Photoconductor 22 Intermediate transfer belts 23BK, 23M , 23Y, 23C Primary transfer bias roller 25 Belt cleaning device 50 Transfer conveyance belt 60 Secondary transfer bias roller

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 is formed by laminating an epoxy-silicone layer containing an epoxy-silicone copolymer on at least a base layer,
The epoxy-silicone layer contains a flame retardant compound and is a surface layer;
The intermediate transfer member, wherein the flame retardant compound is any one selected from melamine sulfate, chlorinated polyethylene, polydibromostyrene, magnesium hydroxide, and zinc borate .   The intermediate transfer member according to claim 1, wherein the content of the flame retardant compound is 1 to 100 parts by weight with respect to 100 parts by weight of the epoxy-silicone copolymer.   The intermediate transfer member according to claim 1, wherein the flame retardant compound has a particle size of 10 μm or less.   The intermediate transfer member according to claim 1, wherein the flame retardant compound is a nitrogen-based compound.   The intermediate transfer member according to claim 1, wherein the flame retardant compound is a chlorine compound.   The intermediate transfer member according to claim 1, wherein the intermediate transfer member is a seamless belt. 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,
A plurality of image carriers corresponding to each color are arranged in series,
8. The image forming apparatus according to claim 7, wherein each of the plurality of latent image carriers has a developing unit corresponding to each color.

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