JP2014238472A - Intermediate transfer belt and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer belt having excellent secondary transferability, and an image forming apparatus using an intermediate transfer system, configured to use the intermediate transfer belt and to be suitable for full-color image formation.SOLUTION: An electrophotographic device includes means for primarily transferring a toner image formed on an image carrier to an intermediate transfer body, and means for secondarily transferring the image primarily transferred on the intermediate transfer body to a transfer material. An intermediate transfer belt for the electrophotographic device includes, from the inside, at least a base layer and a surface layer. The surface layer having an irregular shape formed of spherical resin fine particles is surface-treated by a fluorine-based silane coupling agent.

Description

  The present invention relates to a seamless belt provided in an image forming apparatus such as a copy printer and the like, and an image forming apparatus using the same, and more particularly to an intermediate transfer belt suitable for full-color image formation and an image forming apparatus using the same.

  Conventionally, seamless belts have been used as members for various uses in electrophotographic apparatuses. Particularly in recent full-color electrophotographic apparatuses, an intermediate transfer belt system in which developed images of four colors of yellow, magenta, cyan, and black are once overlaid on an intermediate transfer medium, and then collectively transferred to a transfer medium such as paper. Is used.

  Such an intermediate transfer belt system has been used in a system that uses four color developing devices for one photoconductor, but has a drawback in that the printing speed is slow. For this reason, as a high-speed print, a four-tandem tandem method is used in which the photoreceptors are arranged for four colors and each color is continuously transferred to paper. However, in this method, there are fluctuations due to the environment of the paper, etc., and it is very difficult to match the position accuracy of overlapping each color image, causing a color misregistration image. Therefore, in recent years, it has become the mainstream to adopt the intermediate transfer method for the quadruple tandem method.

  Under such circumstances, the required characteristics (high-speed transfer, positional accuracy) of the intermediate transfer belt are also stricter than before, and it is necessary to satisfy the characteristics corresponding to these requirements. Yes. In particular, for positional accuracy, it is required to suppress fluctuations due to deformation such as elongation of the belt itself due to continuous use. Further, the intermediate transfer belt is laid out over a wide area of the apparatus, and is required to be flame retardant because a high voltage is applied for transfer. In order to meet such requirements, polyimide resins, polyamideimide resins, and the like that are high elastic modulus and high heat resistance resins are mainly used as intermediate transfer belt materials.

  In order to improve secondary transfer performance and cleaning performance, it is effective to reduce the adhesion between the toner and the intermediate transfer member. Therefore, the surface of the base layer made of polyimide resin or polyamideimide resin is formed on the belt by using concave and convex spherical resin particles, whereby the friction coefficient is lowered and toner adhesion can be prevented. As a result, the secondary transfer property and the cleaning property were improved.

  However, dropping of the spherical resin fine particles occurred on the spherical fine particles due to filming of the toner and rubbing against a contact member such as a cleaning blade. (Japanese Patent Laid-Open No. 2011-150059 of Patent Document 1)

  In Patent Document 2, it is supposed that the durability improvement and the cleaning property of the inorganic compound layer are improved by laminating a protective layer having a low friction property on the base layer, the elastic layer, the three-dimensional crosslinkable resin layer, and the inorganic compound layer. In particular, it is desirable to use a fluorine-based silane compound as a protective layer. However, in this proposal, since the uneven surface is not formed on the surface, poor toner cleaning and secondary transferability are deteriorated, and a product satisfying the high level of image quality required for recent electrophotography is obtained. I can't.

  In Patent Document 3, in an elastic composition containing a resin having elasticity and an inorganic filler, water repellency is improved by forming a water-repellent film with a water-repellent film-forming molecule on a part of the exposed inorganic filler surface. If so. The water-repellent film-forming molecule preferably contains a fluorinated carbon group. However, in this proposal, an inorganic additive is mixed with an elastic molding to form a belt. For this reason, problems such as “the surface unevenness shape obtained by intentionally embedding particles on the belt surface” according to the present invention cannot be formed, and the projected area ratio of the exposed particles cannot be controlled well. As a result, toner cleaning failure and secondary transferability are deteriorated, and it is not possible to obtain a product that satisfies the high level of image quality required for recent electrophotography.

  In Patent Documents 4 and 5, it is proposed to form a layer with a material having affinity for the hydrophobized fine particles. In these, particles having a very small particle size are preferably used. However, the particle layer is thick, there are non-uniform portions due to particle aggregation, and the transfer performance also varies, which can satisfy the high level of image quality required of recent electrophotographic devices. I can't get it.

  Patent Documents 6 and 7 propose a configuration in which durability is achieved by using relatively large particles and embedding in resin to some extent. However, even in this proposal, non-uniformity is present in the presence of particles, and it is still impossible to obtain a product that can satisfy the high level of image quality required for recent electrophotographic apparatuses.

  In Patent Documents 4 to 7, silica is preferably used. However, since silica particles have a strong cohesive force, a uniform particle layer cannot be formed as described above. In addition, inorganic particles such as silica tend to scratch and wear the surface of the organic photoreceptor due to contact with the organic photoreceptor that is preferably used as a latent image carrier for image formation, and reduce durability. This causes the problem of

  The present invention has been made in view of the above prior art, and has an intermediate transfer belt excellent in secondary transfer performance, and an intermediate transfer type image forming apparatus using the intermediate transfer belt, particularly suitable for full color image formation. The purpose is to provide.

As a result of intensive studies, the present inventors have made primary transfer of a toner image formed on an image carrier onto an intermediate transfer member and secondary transfer of the primary transferred image on the intermediate transfer member onto a transfer material. As an intermediate transfer belt for an electrophotographic apparatus having a base layer and a surface layer from at least the inner side of the intermediate transfer belt, the surface layer has spherical resin fine particles arranged thereon to form a concavo-convex shape, and the surface layer is further made of a fluorine-based silane coupling. It has been found that the above problem can be solved by providing an intermediate transfer belt surface-treated with an agent.
That is, the present invention relates to an intermediate transfer belt as described below and an image forming apparatus using the same.
(1) “having means for primary transfer of a toner image formed on an image carrier onto an intermediate transfer member and means for secondary transfer of an image primarily transferred on the intermediate transfer member onto a transfer material In the intermediate transfer belt for an electrophotographic apparatus, the intermediate transfer belt has at least a base layer and a surface layer from the inside, the surface layer has an uneven shape by spherical resin fine particles, and the surface layer having the uneven shape is a fluorine-based silane coupling agent. An intermediate transfer belt for electrophotography, which has been surface-treated by the above. "
(2) “The intermediate transfer belt according to (1), wherein the spherical resin fine particles are formed in a concavo-convex shape using a material obtained by previously treating with a fluorine-based silane coupling agent.”
(3) “The intermediate transfer belt according to (1) or (2), wherein a surface layer of the intermediate transfer belt is an elastic layer.”
(4) “The intermediate transfer belt according to any one of (1) to (3), wherein the spherical particle diameter of the intermediate transfer belt is in a range of 1 μm to 5 μm.”
(5) Any one of (1) to (4) above, wherein in the intermediate transfer belt, the projected area ratio of the spherical resin fine particles existing in the elastic layer is 60% or more with respect to the belt surface. The intermediate transfer belt described in Crab. "
(6) “An image carrier on which a latent image is formed and capable of carrying a toner image, a developing unit for developing the latent image formed on the image carrier with toner, and a toner image developed by the developing unit Includes an intermediate transfer belt on which the 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. The intermediate transfer belt includes the intermediate transfer belt (1) to (5). Or an intermediate transfer belt according to any one of the above.
(7) “The image forming apparatus according to (6), wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of latent image carriers having developing units for each color are arranged in series.”

  As will be more apparent from the following detailed and specific description, according to the present invention, an intermediate transfer belt that can be mounted on an electrophotographic apparatus with high image quality that can realize high transfer performance regardless of the type and surface shape of the transfer medium. Thus, an extremely excellent effect is provided that an image forming apparatus equipped with the intermediate transfer belt can be provided.

FIG. 3 is a diagram illustrating a layer configuration of an intermediate transfer belt preferably used in the present invention. It is the figure which showed the enlarged schematic diagram which observed the surface of the belt from right above. It is the figure which showed the formation method of the spherical particle layer which concerns on this invention. It is a principal part schematic diagram for demonstrating the image forming apparatus equipped with the seamless belt obtained by the manufacturing method which concerns on this invention as a belt member. FIG. 2 is a schematic diagram of a main part for explaining an image forming apparatus in which a plurality of photosensitive drums are arranged side by side along a single intermediate transfer belt made of a seamless belt, as shown in a schematic diagram of the main part.

  In an electrophotographic apparatus, a seamless belt is used for several members, and an intermediate transfer member (intermediate transfer belt) is one of important members that require electrical characteristics. The intermediate transfer belt of the present invention will be described below.

The seamless belt of the present invention comprises an intermediate transfer belt type electrophotographic apparatus [a so-called so-called image carrier (for example, a photosensitive drum) in which a plurality of color toner developed images sequentially formed are sequentially superimposed on the intermediate transfer belt. The apparatus is suitably equipped as an intermediate transfer belt in an apparatus that performs primary transfer and performs secondary transfer of the primary transfer image collectively onto a recording medium].
FIG. 1 shows a layer structure of an intermediate transfer belt preferably used in the present invention. As a configuration, a flexible surface layer 12 is laminated on a rigid base layer 11 which can be relatively flexible, and the surface layer 12 has an uneven shape by arranging spherical resin fine particles 13. .

<Base layer>
First, the base layer 11 will be described. Examples of the constituent material include a material containing a filler (or additive) for adjusting electric resistance in the resin, that is, a so-called electric resistance adjusting material.
As such a resin, from the viewpoint of flame retardancy, for example, a fluorine-based resin such as PVDF, ETFE, a polyimide resin or a polyamide-imide resin is preferable, and particularly from the viewpoint of mechanical strength (high elasticity) and heat resistance. A polyimide resin or a polyamideimide resin is preferred.

Examples of the electrical resistance adjusting material include a metal oxide, carbon black, an ionic conductive agent, and a conductive polymer material. Examples of the metal oxide include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. Moreover, in order to improve dispersibility, the metal oxide may be subjected to surface treatment in advance. Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black. Examples of the ionic conductive agent include tetraalkylammonium salts, trialkylbenzylammonium salts, alkylsulfonates, alkylbenzenesulfonates, alkyl sulfates, glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acids. Alcohol ester, alkyl betaine, lithium perchlorate, etc. are mentioned, and these may be used in combination.
The electrical resistance adjusting material in the present invention is not limited to the above exemplary compounds.
In addition, the coating liquid containing at least the resin component in the method for producing a seamless belt of the present invention further contains additives such as a dispersion aid, a reinforcing material, a lubricant, a heat conduction material, and an antioxidant as necessary. May be.

  When used in a seamless belt suitably equipped as the intermediate transfer belt, the resistance value is preferably 1 × 10 ^ 8 to 1 × 10 ^ 13Ω / □ in surface resistance, and 1 × 10 ^ 8 to 1 in volume resistance. The amount of carbon black so as to be × 10 ^ 11 Ω · cm is contained, but from the viewpoint of mechanical strength, a carbon black amount that can be achieved with an addition amount that is not brittle and does not easily break is selected. In other words, in the case of an intermediate transfer belt, an electrical characteristic (for example, a coating liquid in which the blending of the resin component (for example, a polyimide resin precursor or a polyamideimide resin precursor) and an electrical resistance adjusting material is appropriately adjusted is used. It is preferable to manufacture and use a seamless belt having a balance between surface resistance and volume resistance) and mechanical strength.

  There is no restriction | limiting in particular as thickness of the said base layer, Although it can select suitably according to the objective, 30 micrometers-150 micrometers are preferable, 40 micrometers-120 micrometers are more preferable, 50 micrometers-80 micrometers are especially preferable. If the thickness of the base material layer is less than 30 μm, the belt may be easily torn due to cracks, and if it exceeds 150 μm, the belt may be broken by bending. On the other hand, when the thickness of the base layer is within the particularly preferable range, it is advantageous in terms of durability. With respect to the base layer, it is preferable to eliminate film thickness unevenness as much as possible in order to improve running stability.

  The method for adjusting the thickness of the base layer is not particularly limited and may be appropriately selected depending on the purpose. For example, measurement with a contact-type or eddy-current film thickness meter or scanning of a cross section of the film with a scanning electron For example, a method of adjusting the thickness by measuring with a microscope (SEM) may be used.

  In the case of carbon black, the content of the electric resistance adjusting material in the present invention is 10 to 25 wt%, preferably 15 to 20 wt% of the total solid content in the coating liquid. Moreover, as content in the case of a metal oxide, it is 1-50 wt% of the total solid of a coating liquid, Preferably it is 10-30 wt%. When the content is less than the range of each of the electric resistance adjusting materials, it becomes difficult to obtain uniformity of the resistance value, and the fluctuation of the resistance value with respect to an arbitrary potential increases. On the other hand, when the content is larger than the above ranges, the mechanical strength of the intermediate transfer belt is lowered, which is not preferable in practical use.

  As polyimide and polyamideimide in the present invention, general-purpose products from manufacturers such as Toray DuPont, Ube Industries, Nippon Nippon Chemical, JSR, Unitika, IST, Hitachi Chemical, Toyobo, Arakawa Chemical, etc. are obtained. Can be used.

<Surface>
Next, the surface layer 12 laminated on the base layer 11 will be described.
It is possible to use a material such as a general-purpose resin or rubber as a constituent material.

<Resin layer>
Examples of the resin include styrene resin, phenol resin, acrylic resin, methacrylic resin, urethane resin, melamine resin, polyamide resin, polyester resin, polyether resin, polyvinyl ether resin, polyolefin resin, epoxy resin, ketone resin, silicone resin, fluorine resin. And the like. Moreover, these copolymers or a mixture is also included. In order to fully express the effect of the present invention, it is preferable to use a resin that can hold spherical resin fine particles, and in order to increase the affinity with the spherical resin fine particles treated with a fluorine-based silane coupling agent, In order to achieve a low μ, it is desirable to select a fluororesin for the resin layer.

  The fluororesin that is the surface layer of the present invention may be one that is currently on the market and is not particularly limited. Fluoropolymers are commercially available, such as Lumiflon (Asahi Glass) and Neoflon (Daikin Industries).

  As a method for forming the surface layer, existing coating methods such as spiral coating, die coating, and roll coating, spray coating, and the like can be applied. The surface layer coated on the base layer is dried while being leveled by maintaining a predetermined rotation speed and drying temperature. In this drying process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatile solvent) as in the base layer manufacturing method. After sufficiently cooling, the whole base layer is detached from the mold to obtain a seamless belt (intermediate transfer belt).

  There is no restriction | limiting in particular as thickness of the said surface layer, Although it can select suitably according to the objective, 5 micrometers-150 micrometers are preferable, 10 micrometers-100 micrometers are more preferable, 10 micrometers-50 micrometers are especially preferable. If the thickness of the surface material layer is less than 5 μm, the resin fine particles cannot be sufficiently buried, and sufficient mechanical strength cannot be obtained. If it exceeds 150 μm, the belt may be broken by bending. On the other hand, when the thickness of the surface layer is in a particularly preferable range, it is advantageous in terms of durability. Regarding the surface layer, it is preferable to eliminate as much as possible film thickness unevenness in order to improve running stability and toner transferability.

  The method for adjusting the thickness of the surface layer is not particularly limited and may be appropriately selected depending on the purpose. For example, measurement with a contact type or eddy current type film thickness meter or a cross section of the film is a scanning electron. The method of measuring with a microscope (SEM) is mentioned.

<Elastic layer>
The surface layer 12 may be an elastic layer using an elastic body. By using the elastic body, the followability to papers having different surface properties can be improved, and uneven unevenness and color tone of the paper can be prevented. By using the elastic layer, it is possible to transfer to a rough surface material such as recycled paper, embossed paper, Japanese paper or kraft paper.
As a constituent material, a general-purpose resin, elastomer, rubber, or the like can be used as a constituent material, but a material having sufficient flexibility (elasticity) to sufficiently exhibit the effects of the present invention. It is preferable to use an elastomer material or a rubber material.
Examples of the elastomer material include thermoplastic elastomers such as polyester, polyamide, polyether, polyurethane, polyolefin, polystyrene, polyacryl, polydiene, silicone-modified polycarbonate, and fluorine copolymer. . Examples of thermosetting include polyurethane, silicone-modified epoxy, and silicone-modified acrylic.
Examples of the rubber material include isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, chloroprene rubber, acrylic rubber, chlorosulfonated polyethylene, fluorine rubber, urethane rubber, and hydrin rubber. .
From the above-mentioned various elastomers and rubbers, a material capable of obtaining performance is appropriately selected. In the present invention, acrylic rubber is most preferable from the viewpoints of ozone resistance, flexibility, flame resistance, and environmental stability. Hereinafter, the acrylic rubber will be described.

  The acrylic rubber which is the rubber elastic layer of the present invention may be currently marketed and is not particularly limited. However, among the various crosslinking systems (epoxy groups, active chlorine groups, carboxyl groups) of acrylic rubber, the carboxyl group crosslinking system is excellent in rubber properties (especially compression set) and processability, so select the carboxyl group crosslinking system. It is preferable to do.

The crosslinking agent used for the carboxyl group-crosslinked acrylic rubber is preferably an amine compound, and most preferably a polyvalent amine compound. Specific examples of such amine compounds include aliphatic polyvalent amine crosslinking agents and aromatic polyvalent amine crosslinking agents. Examples of the aliphatic polyvalent amine cross-linking agent include hexamethylene diamine, hexamethylene diamine carbamate, and N, N′-dicinnamylidene-1,6-hexane diamine. Aromatic polyvalent amine crosslinking agents include 4,4′-methylenedianiline, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4 ′-(m-phenylenediene. Isopropylidene) dianiline, 4,4 ′-(p-phenylenediisopropylidene) dianiline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-diaminobenzanilide, 4, 4'-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, 1,3,5-benzenetriamine, 1,3,5-benzenetriaminomethyl and the like can be mentioned.
The blending amount of the crosslinking agent is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic rubber. When the blending amount of the crosslinking agent is too small, crosslinking is not sufficiently performed, so that it is difficult to maintain the shape of the crosslinked product. On the other hand, when there is too much content, a crosslinked material will become hard too much and the elasticity etc. as a crosslinked rubber will be impaired.

  In the acrylic rubber elastic layer of the present invention, a crosslinking accelerator may be further blended and used in combination with the crosslinking agent. The crosslinking accelerator is not limited, but is preferably a crosslinking accelerator that can be used in combination with the polyvalent amine crosslinking agent. Examples of such a crosslinking accelerator include guanidine compounds, imidazole compounds, quaternary onium salts, tertiary phosphine compounds, weak metal alkali metal salts, and the like. Examples of the guanidine compound include 1,3-diphenylguanidine, 1,3-diortolylguanidine and the like. Examples of the imidazole compound include 2-methylimidazole and 2-phenylimidazole. Examples of the quaternary onium salt include tetra n-butylammonium bromide and octadecyltri-n-butylammonium bromide. Examples of the polyvalent tertiary amine compound include triethylenediamine and 1,8-diaza-bicyclo [5.4.0] undecene-7 (DBU). Examples of the tertiary phosphine compound include triphenylphosphine and tri-p-tolylphosphine. Examples of the alkali metal salt of a weak acid include inorganic weak acid salts such as sodium or potassium phosphates and carbonates, and organic weak acid salts such as stearates and laurates.

  The amount of the crosslinking accelerator used is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 10 parts by weight per 100 parts by weight of the acrylic rubber. When there are too many crosslinking accelerators, the crosslinking rate may become too fast at the time of crosslinking, the bloom of the crosslinking accelerator on the surface of the crosslinked product may occur, or the crosslinked product may become too hard. If the amount of the crosslinking accelerator is too small, the tensile strength of the crosslinked product may be remarkably reduced, or the elongation change or the tensile strength change after heat load may be too large.

  In preparing the acrylic rubber, an appropriate mixing method such as roll mixing, Banbury mixing, screw mixing, or solution mixing can be employed. The order of blending is not particularly limited, but after sufficiently mixing components that are not easily reacted or decomposed by heat, as a component that is easily reacted by heat or a component that is easily decomposed, for example, a crosslinking agent or the like at a temperature at which reaction or decomposition does not occur. What is necessary is just to mix in a short time.

  Acrylic rubber can be made into a crosslinked product by heating. The heating temperature is preferably 130 to 220 ° C, more preferably 140 to 200 ° C, and the crosslinking time is preferably 30 seconds to 5 hours. As a heating method, a method used for crosslinking of rubber such as press heating, steam heating, oven heating, hot air heating and the like may be appropriately selected. Further, after cross-linking once, post-cross-linking may be performed in order to surely cross-link to the inside of the cross-linked product. Post-crosslinking is preferably performed for 1 to 48 hours, although it varies depending on the heating method, crosslinking temperature, shape, and the like. What is necessary is just to select the heating method and heating temperature at the time of post-crosslinking suitably.

  Further, the flexibility of the rubber elastic layer is preferably such that the micro rubber hardness value at 25 ° C. and 50% RH is 40 or less. The micro rubber hardness can be obtained by using a commercially available micro rubber hardness meter, for example, by using “Micro Rubber Hardness Meter MD-1” of Kobunshi Keiki Co., Ltd.

  On the other hand, the film thickness of the elastic layer is preferably 400 μm to 1000 μm, more preferably 500 μm to 700 μm. If it is 400 μm or less, the image quality for paper types with surface irregularities will be insufficient. When the thickness is 1000 μm or more, the film becomes heavy, becomes easy to bend, the warpage becomes large and the running performance becomes unstable, or cracks occur due to bending at the roller curvature part for stretching the belt. Since it becomes easy, it is not preferable.

  Further, the length in the belt width direction is preferably 300 mm or more from the viewpoint of speeding up, high image quality, and high durability of recent electrophotography.

  The selected material is mixed with a resistance adjuster for adjusting electrical characteristics and, if necessary, a material such as an antioxidant, a reinforcing agent, a filler, and a vulcanization accelerator as appropriate.

  The resistivity control required for the intermediate transfer belt requires the addition of a conductive agent because acrylic rubber alone has a high resistivity. Carbon or an ionic conductive agent can be added to control the resistivity. However, in the present invention, the rubber hardness is important, and therefore it is preferable to use an ionic conductive agent that is effective when added in a small amount and does not affect the rubber hardness. Specifically, it is preferable to add 0.01 to 3 parts of various perchlorates and ionic liquids with respect to 100 parts of rubber. If the addition amount of the ionic conductive agent is 0.01 parts or less, the effect of reducing the resistivity cannot be obtained, and if the addition amount is 3 parts or more, the possibility that the conductive agent blooms or bleeds to the belt surface becomes high. The resistance value of the elastic layer should be adjusted so that the surface resistance is 1 × 10 ^ 8 to 1 × 10 ^ 13Ω / □, and the volume resistance is 1 × 10 ^ 7 to 1 × 10 ^ 12Ω · cm. Is preferred.

<Spherical resin fine particles>
Next, the spherical resin fine particles 13 that form the uneven shape on the surface layer 12 will be described. The spherical resin fine particles are fine particles having an average particle diameter of 100 μm or less and a true spherical shape, insoluble in an organic solvent, and having a 3% thermal decomposition temperature of 200 ° C. or higher.

  The material of the spherical resin fine particles is not particularly limited, but particles having a hydroxyl group in the material structure and capable of reacting strongly with a silane coupling agent described later are preferred. Examples thereof include spherical particles mainly composed of resins such as acrylic resin, melamine resin, polyamide resin, polyester resin, silicone resin, and fluororesin. Further, the surface of particles made of these resin materials may be subjected to surface treatment with a different material. However, in order to sufficiently exhibit the effects of the present invention, silicone spherical fine particles are most preferable as those having slipperiness and a high function capable of imparting releasability and abrasion resistance to the toner.

  Further, the spherical resin fine particles referred to herein include a rubber material. A structure in which the surface of spherical fine particles made of a rubber material is coated with a hard resin is also applicable. Moreover, it may be hollow or porous.

The spherical resin fine particles are preferably particles produced in a spherical shape by a polymerization method or the like, and in the present invention, those closer to a true sphere are more preferable. Moreover, as for the particle size, a volume average particle diameter is 1.0 micrometer-5.0 micrometers, and it is desirable that it is a monodisperse particle. The monodisperse particles referred to here do not mean particles with a single particle diameter but refer to those having a very sharp particle size distribution. Specifically, it may have a distribution width of volume average particle size ± (average particle size × 0.5) μm or less.
When the particle size is 1.0 μm or less, the effect of the transfer performance by the particles cannot be sufficiently obtained. On the other hand, when the particle size is 5.0 μm or more, the surface roughness increases and the particles fall off. Further, since the gap between the particles becomes large, there is a problem that the toner having a particle diameter of 4 to 10 μm, which is currently mainstream, enters the gap and cannot be transferred well or has a poor cleaning. Furthermore, since many particles have high insulating properties, if the particle size is too large, a residual charging potential due to the particles causes a problem that image disturbance occurs due to accumulation of the potential during continuous image output. The timing for applying the particles to the surface of the surface layer is not particularly limited, and in the case of rubber, it can be performed either before or after vulcanization.

  There is no restriction | limiting in particular as said spherical resin fine particle, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available product include silicone particles such as “Tospearl Series” (Momentive Performance Materials) and “KMP Series” (Shin-Etsu Silicone).

<Surface condition of the belt>
Next, the belt surface state in the present invention will be described.
FIG. 2 shows an enlarged schematic view of the belt surface observed from directly above. As described above, the spherical resin fine particles having a uniform particle diameter are independently and regularly arranged. Little overlap between spherical resin particles is observed. The diameter of the cross section of each particle constituting the surface on the resin layer surface is preferably uniform, and specifically, the distribution width is preferably ± (average particle diameter × 0.5) μm or less.
In order to form this, it is preferable to use particles having a uniform particle size as much as possible, but the particle size distribution can be obtained by forming a surface by a method in which particles having a certain particle size can be selectively formed on the surface without using this. It is good also as a structure used as a width | variety.

The projected area ratio of the spherical resin fine particles 13 is preferably 60% or more. If it is 60% or less, the exposed portion of the surface layer 12 is large and the toner comes into contact with the rubber, so that good transferability cannot be obtained.
As for the upper limit, the projected area ratio is preferably closer to 100% in order to reduce the exposed portion.

In the present invention, the spherical resin fine particles are in the form of being partially embedded in the surface layer 12, but the burying rate is preferably more than 50% and less than 100%, preferably 51% to 90%. Is more preferable. If it is 50% or less, the particles are likely to be detached during long-term use in the image forming apparatus, resulting in poor durability. On the other hand, 100% is not preferable because the effect of the particles on the transferability is reduced.
The burial rate is the rate of burial in the resin layer having a diameter in the depth direction of the particles, but the burial rate here means that all particles exceed 50% and do not reach 100%. Instead, the numerical value expressed by the average burial rate when viewed from a certain field of view should be more than 50% and less than 100%. However, when the burial rate is 50%, in the cross-sectional observation by the electron microscope, the particles completely buried in the elastic layer are hardly observed (the number% of the particles completely buried in the elastic layer is the total number of particles). (5% or less).

<Fluorine-based silane coupling agent>
In order to reduce the surface energy of the uneven belt surface, there is also a method of applying a low surface energy resin typified by fluorine resin or silicone resin to the surface, but in that case, since it does not form a direct bond with the resin, The coating agent peels off when the belt is used for a long time.
Therefore, in the present invention, the friction coefficient of the belt and the improvement of the durability are realized by reacting a fluorine-based silane coupling agent directly on the belt surface having an uneven shape.

  After the spherical resin fine particles 13 are exposed on the belt surface to form an uneven shape, a fluorine-based silane coupling agent is directly applied to modify the spherical resin fine particle surface. The fluorine-based silane coupling agent is applied as it is or dissolved in a solvent, and applied by spray coating, dipping or spin coating, and then dried by heating.

Alternatively, the entire surface of the spherical resin fine particles 13 may be previously treated with a fluorine-based silane coupling agent, and then the modified spherical resin particles may be buried in the belt surface to form the uneven shape. The fluorine-based silane coupling agent is used as it is or dissolved in a solvent, mixed with spherical resin fine particles, filtered and dried by heating. Finally, the particles can be washed with a solvent to remove excess fluorine-based silane coupling agent, which is preferable.

<About fluorinated silane coupling agents>
Next, a fluorine-based silane coupling agent that is preferably used as the hydrophilic organic compound in the present invention will be described. The fluorine-based silane compound is an organic silicon compound represented by the following general formula (1), and has a fluorine-containing organic functional group (X) and a hydrolyzable group (SiOR).

上記一般式（１）においてＯＲは加水分解性基から構成される。限定されるものではないが、加水分解性基の一例として、メトキシ基、エトキシ基、プロポキシ基、フェノキシ基、ブトキシ基、シクロヘキシルオキシ基、フェノキシ基、ベンジロキシ基などのエーテル基やアセトキシ基、プロピオニルオキシ基、アクリロキシ基、メタクリロキシ基、ベンゾイルオキシ基、メタンスルホニルオキシ基、ベンゼンスルホニルオキシ基、ベンジロキシカルボニル基などのエステル基、ハロゲン原子（塩素等）などが挙げられる。
上記一般式（１）においてXはフッ素を含む官能基を一部有する有機化合物を示す。限定されるものではないが、フッ素を含む官能基の一例として例えば、トリフルオロメチル基、パーフルオロエチル基、パーフルオロプロピル基、パーフルオロブチル基などのフッ素系アルキル基やフッ素系アルケニルハライド基、フッ素系アリールハライド基が挙げられる。前期フッ素含有官能基は有機化合物中どの位置に任意の数だけ結合していてもいいが、少なくとも1個以上結合している必要がある。

In the general formula (1), OR is composed of a hydrolyzable group. Examples of hydrolyzable groups include, but are not limited to, ether groups such as methoxy group, ethoxy group, propoxy group, phenoxy group, butoxy group, cyclohexyloxy group, phenoxy group, benzyloxy group, acetoxy group, and propionyloxy. Group, acryloxy group, methacryloxy group, benzoyloxy group, methanesulfonyloxy group, benzenesulfonyloxy group, benzylsulfonylcarbonyl group, benzyloxycarbonyl group and other ester groups, and halogen atoms (such as chlorine).
In the general formula (1), X represents an organic compound partially having a functional group containing fluorine. Although not limited, as an example of a functional group containing fluorine, for example, a fluorinated alkyl group such as a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a fluorinated alkenyl halide group, A fluorine-type aryl halide group is mentioned. Any number of the fluorine-containing functional groups may be bonded to any position in the organic compound, but at least one is required to be bonded.

As the fluorine-based silicon compound represented by the general formula (1), a generally known fluorine-based silane coupling agent (hereinafter sometimes referred to as “coupling agent”) can be used. Specific examples of such a coupling agent are shown below.
Trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane, 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl Examples include methyldimethoxysilane, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecylmethyldimethoxysilane.
The fluorine-based silane coupling agent described above may be synthesized by a method as described in JP-A-7-224242, or a commercially available product may be used.
Examples include “Dow Corning 2634 Coating” (made by Toray Dow Coating Co., Ltd.), “OPTOOL AES-2” (made by Daikin Industries, Ltd.), and “KBM-7103” (made by Shin-Etsu Chemical Co., Ltd.). .

As long as the surface treatment agent is a fluorine-based silane coupling agent, one type may be used alone, or a plurality of types may be mixed and used.
Alternatively, the surface-treated spherical resin fine particles and the surface untreated spherical resin fine particles may be mixed. In addition, the presence or absence of a surface treatment agent can be confirmed by infrared spectroscopy (ATR / FT-IR).

  Next, an example of a method for producing the belt having the configuration of the present invention will be described. First, a method for producing the base layer 11 will be described.

A method for producing a base layer using the coating liquid containing at least the resin component of the present invention, that is, the coating liquid containing the polyimide resin precursor or the polyamideimide resin precursor will be described.
While slowly rotating a cylindrical mold, for example, a cylindrical metal mold, a coating liquid containing at least a resin component (for example, a coating liquid containing a polyimide resin precursor or a polyamideimide resin precursor) is used as a nozzle or Application and casting (formation of a coating film) is performed uniformly on the entire outer surface of the cylinder by a liquid supply device such as a dispenser. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and the rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is formed, the mold is transferred to a heating furnace (firing furnace) capable of high-temperature processing, and the temperature is raised stepwise, and finally high-temperature heat processing (firing is performed at about 250 ° C. to 450 ° C. And sufficiently imidizing or polyimidizing the polyimide resin precursor or the polyamideimide resin precursor. After sufficiently cooling, the surface layer 12 is subsequently laminated.

<Production method when the surface layer is a resin layer>
The surface layer 12 can be produced by applying and forming a resin coating in which a resin is dissolved in an organic solvent on a base layer, and then drying and vulcanizing the solvent. As a coating molding method, the same method as the base layer is taken. Application and casting (formation of a coating film) is performed uniformly on the entire surface of the base layer using a liquid supply device. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and the rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is formed, the mold is transferred to a heating furnace (firing furnace) capable of high-temperature processing, and the temperature is raised stepwise to obtain a laminated belt.

<Production method when the surface layer is an elastic layer>
The elastic layer 12 can be manufactured by applying and forming on a base layer using a rubber paint in which rubber is dissolved in an organic solvent, and then drying and vulcanizing the solvent. As the coating molding method, as with the base layer, existing coating methods such as spiral coating, die coating, and roll coating can be applied, but the thickness of the elastic layer may be increased in order to improve uneven transferability. As a coating method for forming a thick film, die coating and spiral coating are excellent, and as described above, spiral coating is preferable because the thickness of the elastic layer can be easily changed in the width direction. Are better. Therefore, here, spiral coating will be described. First, while rotating the base layer in the circumferential direction, while continuously supplying rubber paint with a round or wide nozzle, the nozzle is moved in the axial direction of the base layer, and the paint is spirally applied on the base layer. . The paint applied spirally on the base layer is dried while being leveled by maintaining a predetermined rotation speed and drying temperature. Thereafter, it is formed by further vulcanization (crosslinking) at a predetermined vulcanization temperature. In order to change the film thickness in the width direction, it can be produced by changing the discharge amount of the nozzle, the distance between the nozzle dies, or changing the rotational speed of the dies.

<Belt surface preparation method using spherical resin fine particles>
The case where spherical resin fine particles are applied as a surface treatment method on the surface of the surface layer will be described. The laminated belt is subsequently coated with spherical resin fine particles on the surface layer 12 to form a spherical resin fine particle 1 uneven shape to obtain a desired seamless belt (intermediate transfer belt). As shown in FIG. 3, a spherical particle layer is formed by installing a powder supply device 105 and a pressing member 103, and uniformly coating spherical resin fine particles on the surface from the powder supply device 105 while rotating. The spherical resin fine particles applied to the resin are pressed at a constant pressure while being heated by the pressing member 103. The pressing member 103 removes excess particles while burying the particles in the resin layer. In the present invention, since monodispersed spherical resin fine particles are used in particular, it is possible to form a uniform single particle layer by a simple process of only the leveling process using such a pressing member. The burial rate is adjusted by adjusting the pressing time of the pressing member here.
The adjustment of the burial ratio of the particles in the surface layer may be possible by other methods, but can be easily achieved by, for example, adjusting the pressing force of the pressing member (103). For example, although it depends on the viscosity of the casting coating solution, the solid content, the amount of solvent used, the particle material, etc., as a guideline, when the casting coating solution has a viscosity of 100 to 100,000 mPa · s, the pressing force is 1 mN / cm. By setting the range to ˜1000 mN / cm, the burying rate of 50% to 100% can be achieved relatively easily.
The spherical resin fine particles are uniformly arranged on the surface, and then heated at a predetermined temperature and a predetermined time while rotating to form a belt in which the particles are hardened and embedded.

<Coating method on belt surface>
A surface treatment method for the belt surface having the irregular shape will be described. As the coating method, spray coating method, dipping method, spin coating method, as well as existing coating methods such as spiral coating, die coating, roll coating, etc. can be applied in the same way as when forming the base layer or surface layer. . The spray coating method is excellent because of its relatively low solution viscosity and its simplicity. The coating material applied on the belt is dried while being leveled by maintaining a predetermined rotation speed and drying temperature. Even in this drying process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent).
After sufficiently cooling, the whole base layer is detached from the mold to obtain a seamless belt (intermediate transfer belt).

<Belt surface preparation method when spherical resin fine particle surface is modified in advance>
A surface treatment method for the spherical resin fine particles 13 will be described. A surface treatment agent is added to the organic solvent in which the spherical resin fine particles 13 are dispersed, and the mixture is heated and stirred for a predetermined time, and then only the fine particles are filtered. In order to remove unreacted substances, the organic solvent is washed and dried by heating.
The modified spherical resin fine particles are similarly applied to the surface of the laminated belt by the above-described method, and are uniformly embedded in the resin layer using the powder supply device 105 and the pressing member 103. The spherical resin fine particles are uniformly arranged on the surface, and then heated at a predetermined temperature and a predetermined time while rotating to form a belt in which the particles are hardened and embedded.

<Method for Measuring Buried Ratio of Spherical Resin Fine Particles on Intermediate Transfer Belt>
The method for measuring the burying rate of the spherical resin fine particles in the intermediate transfer belt is not particularly limited and can be appropriately selected according to the purpose. For example, the cross section of the intermediate transfer member is placed on a scanning electron microscope (SEM). It can be measured by observing.

  The method for measuring the projected area ratio of the exposed portion of the particles on the intermediate transfer belt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the surface of the intermediate transfer belt is scanned with a scanning electron microscope ( A method of observing with SEM, binarizing the image using image processing software (Image-plus; cybernetics), and calculating the projected area ratio of the exposed portion of the elastic body and the exposed portion of the particle, etc. Is mentioned.

  Furthermore, the method for measuring the projected area ratio of each particle type on the intermediate transfer belt is not particularly limited and can be appropriately selected according to the purpose. For example, the surface of the intermediate transfer member is scanned with a scanning electron microscope (SEM). ), The type of spherical particles can be determined by elemental analysis using an energy dispersive X-ray analyzer (EDX), and the projected area ratio of the target particle type in the observation range can be calculated. In order to increase the measurement accuracy, it is desirable that at least 100 particles are present in the observation range.

  The resistance of the intermediate transfer belt thus manufactured is adjusted by varying the amounts of carbon black and ionic conductive agent. At this time, it should be noted that the resistance is easily changed depending on the size of the particle and the projected area ratio. The resistance can be measured by using a commercially available measuring instrument, for example, by using Hiresta manufactured by Dia Instruments.

<Image forming apparatus>
The image forming apparatus of the present invention includes an image carrier that can form a latent image and can carry a toner image, a developing unit that develops the latent image formed on the image carrier with toner, and a developing unit that develops the latent image. An intermediate transfer body on which the toner image is primarily transferred, and a transfer means for secondary transfer of the toner image carried on the intermediate transfer body to a recording medium, and further appropriately selected as necessary It has other means, for example, static elimination means, cleaning means, recycling means, control means and the like.
In this case, it is preferable that the image forming apparatus is a full-color image forming apparatus, in which a plurality of latent image carriers having developing units for respective colors are arranged in series.

  A seamless belt used in a belt constituting unit provided in an electrophotographic apparatus (hereinafter referred to as “image forming apparatus”) in the present invention will be described in detail below with reference to a schematic diagram of a main part. The schematic diagram is an example, and the present invention is not limited to this.

FIG. 4 is a schematic diagram of a main part for explaining an image forming apparatus equipped with a seamless belt obtained by the manufacturing method according to the present invention as a belt member. The lubrication application mechanism including the lubricant application brush 505 may or may not be provided as necessary, but in this case, the case where it is installed will be described.
An intermediate transfer unit 500 including a belt member shown in FIG. 4 includes an intermediate transfer belt 501 that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt 501, a secondary transfer bias roller 605 that is a secondary transfer charge applying unit of the secondary transfer unit 600, a belt cleaning brush 504 that is an intermediate transfer member cleaning unit, and a lubricant for a lubricant application unit. A lubricant application brush 505 or the like that is an application member is disposed so as to face each other.

  A position detection mark (not shown) is provided on the outer peripheral surface or the 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 brush 504, which may be difficult to arrange. A position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt 501. An optical sensor 514 serving as a mark detection sensor is provided at a position between the primary transfer bias roller 507 and the belt driving roller 508 where the intermediate transfer belt 501 is bridged.

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

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

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

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

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

For example, the Bk toner image formation is performed as follows.
In FIG. 4, a charging charger 203 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with a negative charge by corona discharge. The timing is determined based on the belt mark detection signal, and raster exposure with laser light is performed based on the Bk color image signal by a writing optical unit (not shown). When this raster image is exposed, the charge proportional to the exposure light amount disappears in the exposed portion of the surface of the photosensitive drum 200 that is initially uniformly charged, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing device 231K comes into contact with this Bk electrostatic latent image, the toner does not adhere to the remaining portion of the photosensitive drum 200, and the charge is not charged. The toner is attracted to the unexposed portion, that is, the exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

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

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

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

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

  On the other hand, the surface of the photosensitive drum 200 after the belt transfer is cleaned by the photosensitive member cleaning device 201 and is uniformly discharged by the discharging lamp 202. Further, residual toner remaining on the outer peripheral surface of the intermediate transfer belt 501 after the toner image is secondarily transferred to the transfer paper P is cleaned by the belt cleaning brush 504. The belt cleaning brush 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). The belt cleaning brush 504 may apply a voltage as necessary.

  On the upstream side of the belt cleaning brush 504 in the moving direction of the intermediate transfer belt 501, a seal member 502 is provided that contacts and separates from the belt outer peripheral surface of the intermediate transfer belt 501. The seal member 502 receives the falling toner that has dropped from the belt cleaning brush 504 during cleaning of the residual toner, and prevents the falling toner from scattering on the transfer path of the transfer paper P. The 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 brush 504 by the cleaning member separating and contacting mechanism.

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

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

In the above-described embodiment, the copying machine including only one photosensitive drum 1 has been described. However, the present invention includes a plurality of photosensitive drums as shown in a configuration example in a schematic diagram of a main part in FIG. The present invention can also be applied to an image forming apparatus arranged side by side along one intermediate transfer belt formed of a seamless belt.
FIG. 5 shows a configuration of a four-drum type digital color printer including four photosensitive drums 21BK, 21Y, 21M, and 21C for forming toner images of four different colors (black, yellow, magenta, and cyan). An example is shown.

  In FIG. 5, 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 into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation and transmits them to the image writing unit 12. To do. The image writing unit 12 is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group. Image writing corresponding to each color signal is performed on image carriers (photoconductors) 21BK, 21M, 21Y, and 21C that have a writing optical path and are provided for each color of the image forming unit 13.

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

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

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

  EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Is also within the scope of the present invention. The film thickness at the center of the belt was calculated by obtaining the average film thickness of the average film thickness of ± 50 mm in the center in the width direction. The film thickness was measured with a contact-type film thickness meter. In addition, the projected area ratio was measured by observing the surface of the belt with a scanning electron microscope (SEM), binarizing the image using image processing software (Image-plus; cyber-netics), and forming a spherical resin on the belt surface. The projected area ratio of the fine particles was calculated.

[Example 1]
A base layer coating solution was prepared as follows, and a seamless belt base layer was prepared using this coating solution.
"Preparation of coating solution for base layer"
First, carbon black (Special Black 4; Evonik Degussa Co., Ltd.) dispersed in N-methyl-2-pyrrolidone with a bead mill in advance in a polyimide varnish (U-varnish A; Ube Industries, Ltd.) containing a polyimide resin precursor as a main component. (Manufactured) was prepared so that the carbon black content was 17% by weight of the polyamic acid solid content, and well stirred and mixed to prepare a coating solution.

"Production of polyimide base belt"
Next, a metal cylindrical support whose outer surface having an outer diameter of 500 mm and a length of 400 mm was roughened by blasting was used as a mold and attached to a roll coater.
Subsequently, the base layer coating liquid A was poured into the pan, the paint was pumped up at a rotation speed of the application roller of 40 mm / sec, and the thickness of the paint on the application roller was controlled by setting the gap between the regulation roller and the application roller to 0.6 mm.
Thereafter, the rotational speed of the cylindrical support is controlled to 35 mm / sec to be close to the application roller, and the coating on the application roller is uniformly transferred onto the cylindrical support with a gap of 0.4 mm from the application roller. While maintaining the rotation, it was put into a hot air circulating dryer, gradually heated to 110 ° C. and heated for 30 minutes, further heated to 200 ° C. for 30 minutes, and the rotation was stopped. Then, this was introduced into a heating furnace (firing furnace) capable of high temperature treatment, and the temperature was raised stepwise to 320 ° C., followed by heat treatment (firing) for 60 minutes. After sufficiently cooling, a polyimide base layer belt having a film thickness of 30 μm was obtained.

"Production of surface layer"
After that, it is taken out from the dryer and cooled, and the cylindrical support is rotated with a fluororesin (Lumiflon LF916F: manufactured by Asahi Glass) dissolved in an organic solvent (MEK: methyl ethyl ketone) at a concentration of 40 wt% on the belt surface. The surface layer was then spirally coated. The coating amount was such that the final film thickness at the center was 60 μm. Then, the coated cylindrical support was put into a hot air circulating dryer while rotating as it was, heated to 100 ° C. at a heating rate of 4 ° C./min, and heated for 30 minutes.

"Production of uneven shape"
3 is removed from the dryer and cooled, and on this surface, using the apparatus shown in FIG. 3, silicone spherical resin fine particles (Tospearl 120 (volume average particle size 2.0 μm product); Momentive Performance Materials) are used as spherical resin fine particles. Was applied evenly on the surface. The pressing member of the polyurethane rubber blade was pressed with a pressing force of 100 mN / cm and fixed to the resin layer. Subsequently, it was again put into a hot air circulating dryer, heated to 170 ° C. at a heating rate of 4 ° C./min, and heat-treated for 60 minutes.

"Application of coating material"
Thereafter, the belt is removed from the dryer, cooled, and a fluorine-based silane coupling agent (Dow Corning 2634 Coating: Toray Dow Coating Co., Ltd.) dissolved in a fluorine-based organic solvent hydridofluoroether (Novec HFE-7200: Sumitomo 3M Limited) on the belt surface. Was spray-coated on the surface layer while rotating the cylindrical support. Then, the coated cylindrical support was put into a hot air circulating dryer while rotating as it was, heated up to 50 ° C. at a heating rate of 4 ° C./min, and heated for 60 minutes. After sufficiently cooling and drying at room temperature for 12 hours, the intermediate transfer belt A was obtained by removing it from the mold. At this time, the projected area ratio of the silicone fine particles was 75%.

[Example 2]
An intermediate transfer belt B was obtained in the same manner as in Example 1 except that “preparation of concavo-convex shape / application of coating material” was the following. The projected area ratio of the particles at this time was 73%.

"Modification of the surface of spherical resin particles"
Silicone as spherical resin fine particles in fluorine-based organic solvent hydrofluoroether (Novec HFE-7200: Sumitomo 3M Limited) in which fluorine-based silane coupling agent (Dow Corning 2634 Coating: manufactured by Toray Dow Coating Co., Ltd.) is dissolved Fine particles (Tospearl 120 (volume average particle size 2.0 μm product); Momentive Performance Materials) were stirred and dispersed, and then only the particles were filtered, heated to 50 ° C. and heated for 60 minutes. Thereafter, it was washed with methanol and then naturally dried for 6 hours.

"Production of uneven shape"
The modified silicone fine particles were uniformly applied to the surface of the belt taken out from the dryer and cooled using the apparatus shown in FIG. The pressing member of the polyurethane rubber blade was pressed with a pressing force of 100 mN / cm and fixed to the resin layer. Subsequently, it was again put into a hot air circulating dryer, heated to 170 ° C. at a temperature rising rate of 4 ° C./min, and heat-treated for 60 minutes to obtain an intermediate transfer belt B.

[Example 3]
An intermediate transfer belt C was obtained in the same manner as in Example 2 except that “preparation of surface layer” was the following. At this time, the projected area ratio of the particles was 80%.

"Production of elastic layer on polyimide base belt"
A rubber composition was prepared by blending and kneading the components shown below in the proportions described above.

Acrylic rubber (Nippon ZEON Co., Ltd./NipolAR12) ・ ・ ・ 100 parts by weight Stearic acid (bead stearic acid Tsubaki made by NOF CORPORATION) ・ ・ ・ 1 part by weight Red phosphorus (Rin Chemical Industry Co., Ltd.) NOVAEXCEL 140F) ... 10 parts by weight Aluminum hydroxide (Heidilite H42M, Showa Denko KK) ... 40 parts by weight Crosslinker (DuPont Dow Elastomer Japan Diak.No1 (Hexamethylenediamine Carbamate) ) ..... 0.6 parts by weight Cross-linking accelerator (Safic alcan VULCOFAC ACT55 (70% 1,8-diazabicyclo (5,4,0)
Salt of undecene-7 and dibasic acid, 30% amorphous silica)) ... 0.6 parts by weight conductive agent (QAP-01 (tetrabutyl ammonium perchlorate) manufactured by Nippon Carlit Co., Ltd.) ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.3 parts by weight

  Next, the rubber composition thus obtained was dissolved in an organic solvent (MIBK: methyl isobutyl ketone) to prepare a rubber solution having a solid content of 35 wt%. The cylindrical support having the polyimide base layer was rotated and moved to the support axis method while continuously discharging the rubber paint from the nozzle, and was coated in a spiral shape. The coating amount was such that the final film thickness at the center was 550 μm. Thereafter, the cylindrical support coated with the rubber paint was put into a hot air circulating dryer while rotating as it was, heated up to 100 ° C. at a heating rate of 4 ° C./min, and heated for 120 minutes.

[Example 4]
In the treatment of the belt of Example 3, the same procedure as in Example 3 was conducted except that silicone fine particles (X-52-854 (volume average particle size 0.8 μm product); Shin-Etsu Chemical) were used as the spherical resin fine particles. A transfer belt D was obtained. At this time, the projected area ratio of the grains was 85%.

[Example 5]
In the treatment of the belt of Example 3, in the same manner as in Example 1 except that silicone fine particles (Tospearl 2000B (volume average particle system 6.0 μm product); Momentive Performance Materials) were used as spherical resin fine particles, Intermediate transfer belt E was obtained. At this time, the projected area ratio of the particles was 70%.

[Example 6]
An intermediate transfer belt F was obtained in the same manner as in Example 3, except that the projected area ratio of the silicone fine particles used as the spherical resin fine particles in Example 5 was changed to 51%.

[Comparative Example 1]
An intermediate transfer belt G was obtained in the same manner as in Example 1 except that the surface of the belt in Example 1 was not modified by fluorine-based silane coupling. At this time, the projected area ratio of the particles was 73%.

[Comparative Example 2]
An intermediate transfer belt H was obtained in the same manner as in Example 3 except that the surface of the spherical resin fine particles in Example 3 was not modified by fluorine-based silane coupling. At this time, the projected area ratio of the particles was 71%.

[Comparative Example 3]
Similar to Example 3 except that the surface of the spherical resin fine particle of Example 3 was modified with hexyltrimethoxysilane (KBM3063: manufactured by Shin-Etsu Silicone) as an aliphatic silane coupling agent instead of fluorine-based silane coupling. Thus, an intermediate transfer belt I was obtained. At this time, the projected area ratio of the grains was 78%.

[Comparative Example 4]
An intermediate transfer belt J was obtained in the same manner as in Example 3 except that the spherical resin fine particle surface of Example 3 was pre-coated with a fluororesin (Lumiflon LF916F: manufactured by Asahi Glass) instead of fluorine-based silane coupling. At this time, the projected area ratio of the grains was 81%.

[Comparative Example 5]
Intermediate transfer in the same manner as in Example 3 except that the following operations were performed instead of “Modification of the surface of spherical resin fine particles” “Preparation of elastic layer on polyimide base belt” and “Preparation of irregular shape” in Example 3 Belt I was obtained.

“Preparation of elastic layer with spherical resin particles”
A rubber composition was prepared by blending and kneading the components shown below in the proportions described above.
Acrylic rubber (Nippon Zeon Co., Ltd./NipolAR12) ······ 100 parts by weight Silicone fine particles (Momentive Performance Materials)
Tospearl 120) ·························· 10 parts by weight Stearic acid (Bead stearate Tsubaki made by NOF Corporation) Part Red phosphorus (Nova Excel 140F manufactured by Rin Chemical Industry Co., Ltd.) 10 parts by weight Aluminum hydroxide (Hidelite H42M manufactured by Showa Denko KK) 40 parts by weight Cross-linking agent (DuPont Dow Elastomer Japan) Diak.No1
(Hexamethylenediamine carbamate) ... 0.6 parts by weight Cross-linking accelerator (Safic alcan VULCOFAC ACT55 (70% 1,8-diazabicyclo (5,4,0) undecene) Salt of -7 and dibasic acid, 30% amorphous silica)) ... 0.6 parts by weight Conductive agent (QAP-01 (tetrabutylammonium perchlorate) manufactured by Nippon Carlit Co., Ltd.) ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.3 parts by weight

  Next, the rubber composition thus obtained was dissolved in an organic solvent (MIBK: methyl isobutyl ketone) to prepare a rubber solution having a solid content of 35 wt%. The cylindrical support having the polyimide base layer was rotated and moved to the support axis method while continuously discharging the rubber paint from the nozzle, and was coated in a spiral shape. The coating amount was such that the final film thickness at the center was 550 μm. Thereafter, the cylindrical support coated with the rubber paint was put into a hot air circulating dryer while rotating as it was, heated up to 100 ° C. at a heating rate of 4 ° C./min, and heated for 120 minutes.

"Application of coating material"
Thereafter, the belt is removed from the dryer, cooled, and a fluorine-based silane coupling agent (Dow Corning 2634 Coating: Toray Dow Coating Co., Ltd.) dissolved in a fluorine-based organic solvent hydridofluoroether (Novec HFE-7200: Sumitomo 3M Limited) on the belt surface. Was spray-coated on the surface layer while rotating the cylindrical support. Then, the coated cylindrical support was put into a hot air circulating dryer while rotating as it was, heated up to 50 ° C. at a heating rate of 4 ° C./min, and heated for 60 minutes. After sufficiently cooling and drying at room temperature for 12 hours, the intermediate transfer belt K was obtained by removing it from the mold. At this time, the projected area ratio of the grains was 8%.

  The intermediate transfer belts A to K of the above examples and comparative examples were mounted on the image forming apparatus of FIG. 5 and evaluated as follows. In FIG. 5, a lubricant application device 27 is provided to provide a mechanism for applying a solid lubricant. However, in the examples in this report, a test was conducted without using the lubricant application device.

<Measurement of transfer rate>
As the transfer paper, concavo-convex paper (continuous quantity 175 kg paper, resack paper) is used, and an operation to output a blue solid image is performed on this, and the amount of image toner on the intermediate transfer belt before transfer to the paper is transferred to the paper Thereafter, the amount of toner remaining on the intermediate transfer belt was measured, and the transfer rate was calculated.

<Measurement of transfer rate at the time of continuous image output of 250,000 sheets>
The transfer rate was measured in accordance with the method of Equation 1 above, after the initial transfer before outputting 250,000 continuous images of the test chart and after the transfer. Judgment was made with a transfer rate of 95-100%, a transfer rate of 95-90%, and a transfer rate of 90% or less.

<Image evaluation at the time of continuous image output of 250,000 sheets>
After 250,000 continuous images of the test chart were output, the image quality of the plain paper (TYPE 6200) (entire halftone with black toner) was judged visually. In the judgment, ◎ indicates that there is no unevenness in image quality, ○ indicates that there is unevenness, but the usable level, and x indicates that it cannot be used.
The results are shown in Table 1.

  From the above results, according to the present invention, it is possible to provide an intermediate transfer belt to be mounted on a high-quality electrophotographic apparatus capable of expressing high transfer performance by reducing the belt size and increasing durability.

(Reference numerals in FIGS. 1 and 2)
DESCRIPTION OF SYMBOLS 11 Base layer 12 Surface layer 13 Spherical resin fine particle 14 Fluorosilane coupling agent

(Reference in FIG. 3)
DESCRIPTION OF SYMBOLS 101 Mold drum 102 Belt 103 which apply | coated base layer and surface layer Pressing member 104 Spherical resin fine particle 105 Powder coating apparatus

(Reference in FIG. 4)
P Transfer paper L Laser light 70 Static elimination roller 80 Ground roller 200 Photoconductor drum 201 Photoconductor cleaning device 202 Static elimination lamp 203 Charger charger 204 Potential sensor 205 Image density sensor 210 Belt transport device 230 Revolver development unit 231Y Y developer 231K Bk developer 231C C developing machine 231M M developing machine 270 fixing device 271 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 502 seal member 503 charging charger 504 belt cleaning brush 505 lubricant application brush 506 lubricant 507 primary transfer bias roller 508 belt Driving roller 509 Belt tension roller 510 Secondary transfer counter roller 511 Cleaning counter roller 512 Feedback current detection roller 13 toner image 514 optical sensor 600 the secondary transfer unit 601 transfer sheet guide plate 605 secondary transfer bias roller 606 transfer paper discharger 608 cleaning blade 610 a registration roller 801 primary transfer power supply 802 secondary transfer power supply

(Reference in FIG. 5)
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 25 Belt cleaning member 26 Drive roller 27 Lubricant coating device 50 Transfer conveyor belt 60 Secondary transfer bias roller

JP 2011-150059 A JP 2011-257586 A JP 2010-229180 A JP 2002-162767 A JP 2004-354716 A JP 2007-328165 A JP 2009-75154 A

Claims (7)

For an electrophotographic apparatus having means for primarily transferring a toner image formed on an image carrier onto an intermediate transfer member, and means for secondary transfer of an image primarily transferred on the intermediate transfer member onto a transfer material In this intermediate transfer belt, the intermediate transfer belt has at least a base layer and a surface layer from the inside, the surface layer has an uneven shape by spherical resin fine particles, and the surface layer having the uneven shape is surface-treated with a fluorine-based silane coupling agent. An intermediate transfer belt for electrophotography, characterized in that 2. The intermediate transfer belt according to claim 1, wherein the spherical resin fine particles are formed in a concavo-convex shape using a material obtained by previously treating with a fluorine-based silane coupling agent. The intermediate transfer belt according to claim 1, wherein a surface layer of the intermediate transfer belt is an elastic layer. The intermediate transfer belt according to any one of claims 1 to 3, wherein a spherical particle diameter of the intermediate transfer belt is in a range of 1 µm to 5 µm. 5. The intermediate transfer belt according to claim 1, wherein in the intermediate transfer belt, a projected area ratio of spherical resin fine particles existing in the elastic layer is 60% or more with respect to the belt surface. . A latent image is formed and an image carrier capable of carrying a toner image; a developing unit that develops the latent image formed on the image carrier with toner; and a toner image developed by the developing unit is primarily transferred. 6. The intermediate transfer belt according to claim 1, further comprising: an intermediate transfer belt; and a transfer unit that secondarily transfers a toner image carried on the intermediate transfer member to a recording medium. An image forming apparatus comprising an intermediate transfer belt. The image forming apparatus according to claim 6, wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of latent image carriers having developing units for respective colors are arranged in series.

Images