JP2013092667A - Intermediate transfer belt, image forming apparatus, and manufacturing method of intermediate transfer belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer belt that is flexible, has excellent toner releasability, achieves high transfer rate irrespective of the types of transfer media, prevents the occurrence of wear on edges of the belt for a long period, has excellent durability, and can form high-quality electrophotographic images; and a manufacturing method of the intermediate transfer belt.SOLUTION: A toner image obtained by developing a latent image formed on an image carrier with toner is transferred onto an intermediate transfer belt. The intermediate transfer belt includes: a base layer 11; an elastic layer 12 laminated on the base layer 11; and an edge protection layer 14 that is formed on an outermost surface of an elastic layer 12 and both edges of the intermediate transfer belt. The elastic layer 12 contains an elastic body and spherical resin particles 13; the spherical resin particles 13 are arranged in a surface direction on a surface of the elastic layer 12. The edge protection layer 14 contains resin.

Description

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

  Conventionally, in an electrophotographic image forming apparatus (hereinafter also referred to as an electrophotographic apparatus or simply an image forming apparatus), a seamless belt is used as a member for various purposes. 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. Are used, and a seamless belt is employed as an intermediate transfer belt.

  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 printing, a four-tandem tandem system is used in which the photoreceptors are arranged for four colors (four), 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 fluctuation 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.

  However, 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 locally aggregates and a part of the image is formed. A so-called hollow image that is not transferred 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 normal smooth paper, recycled paper and embossed paper can be used not only from smooth paper but also from slippery and highly smooth paper such as coated paper. In recent years, products with rough surface properties such as Japanese paper and kraft paper have been 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 order to solve this problem, various intermediate transfer belts in which a relatively flexible elastic layer is laminated on a base layer have been proposed.

  However, the intermediate transfer belt provided with such a relatively flexible elastic layer has a disadvantage that it is inferior in wear resistance and scratch resistance. A general image forming apparatus has a mechanism for cleaning toner remaining on the surface of the intermediate transfer belt after the toner image is transferred. In this mechanism, in order to prevent the cleaned toner from scattering outside. The seal member is brought into contact with both end portions of the intermediate transfer belt. In the case of an intermediate transfer belt having a structure in which a relatively flexible elastic layer is laminated on a base layer, the elastic layers at both ends of the intermediate transfer belt may be worn particularly by contact with the seal member. The worn elastic layer component comes into contact with the photosensitive member and an abnormal image such as white spots is generated, or the end portion is scraped, resulting in unstable running of the intermediate transfer belt and image distortion.

  As a method for solving the above problem, in Patent Document 1, the both ends of the intermediate transfer belt provided with the elastic layer are inclined at an acute angle toward the belt width direction outside with respect to the belt traveling direction, and along the end. Thus, there has been proposed a technique of providing a reinforcing member that has a concave and convex shape that is continuously repeated in the belt traveling direction. However, in the technique according to Patent Document 1, since the reinforcing member is installed using an adhesive such as a double-sided tape, the reinforcing member is detached due to deterioration of the adhesive or the like when used for a long time. Therefore, it cannot be said to satisfy the long life and high durability required for the recent electrophotographic apparatus.

  Patent Document 2 proposes a technique in which the end of the intermediate transfer belt is less likely to be broken by eliminating the elastic layers at both ends of the elastic intermediate transfer belt. However, in the case of the technique according to Patent Document 2, since the film thickness of the belt end portion becomes extremely thin due to the absence of the elastic layers at both ends, the overall balance is deteriorated and the belt running becomes unstable. Furthermore, when an electrophotographic apparatus equipped with a cleaning mechanism for cleaning toner by applying a bias to residual toner is used, the bias leaks from a portion where the elastic layers at both ends do not exist, resulting in a defective cleaning. Occurs.

Patent Documents 3 to 6 propose a technique for attaching fine particles to the surface as a method for protecting the surface of the elastic intermediate transfer belt.
In Patent Documents 3 and 4, as a method for protecting the surface of the elastic intermediate transfer belt, a technique of forming a layer with a material having affinity for the hydrophobized particles is proposed. Particles are preferably used. However, when such small particle size particles are used, the particles are detached due to long-term use, and the long life and high durability required for the recent electrophotographic apparatus cannot be obtained.
Patent Documents 5 and 6 propose a configuration that achieves durability by using relatively large particles and embedding in resin to some extent. However, in the configurations according to Patent Documents 5 and 6, although a certain degree of durability can be obtained, non-uniformity occurs in the presence of particles, and a high level of image quality required for recent electrophotographic apparatuses can be satisfied. I can't get anything.

  In all of Patent Documents 3 to 6, silica is preferably used. However, since silica particles have a strong cohesive force, a uniform particle layer cannot be formed, and high image quality cannot be obtained. 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, is flexible, has excellent toner releasability, can achieve a high transfer rate irrespective of the transfer medium, and causes belt end wear over a long period of time. Another object of the present invention is to obtain an intermediate transfer belt that is excellent in durability and enables high-quality electrophotographic image formation, and a method for producing the intermediate transfer belt.
In addition, the present invention includes the intermediate transfer belt, and is a highly durable and high-quality image capable of maintaining high transfer performance not only initially but also for a long period of time regardless of the type and surface properties of the transfer medium. The object is to obtain a forming device.

In order to solve the above problems, an intermediate transfer belt according to the present invention is an intermediate transfer belt to which a toner image in which a latent image formed on an image carrier is developed with toner is transferred. An elastic layer laminated thereon, and end protection layers formed on the outermost surface on the elastic layer side and at both ends of the intermediate transfer belt, the elastic layer comprising an elastic body and spherical resin particles The spherical resin particles are arranged in a plane direction on the surface of the elastic layer, and the end protective layer contains a resin.
In order to solve the above problems, an image forming apparatus according to the present invention includes an image carrier capable of carrying a toner image in which a latent image is formed and the latent image is developed with toner, and the image carrier on the image carrier. Developing means for developing the latent image formed on the toner with toner, an intermediate transfer belt on which the toner image developed by the developing means is primarily transferred, and toner carried on the intermediate transfer belt Transfer means for secondary transfer of an image to a recording medium, and the intermediate transfer belt is the intermediate transfer belt.
Furthermore, in order to solve the above-described problems, the intermediate transfer belt manufacturing method according to the present invention is a manufacturing method for manufacturing the above-described intermediate transfer belt, the step of forming the base layer and the step of forming the elastic layer A step of uniformly drying and applying the spherical resin particles on the elastic layer, a step of uniformly forming the spherical resin particles by arranging and embedding the spherical resin particles, and the edge protection. Forming a layer.

According to the present invention, there is flexibility, excellent toner releasability, a high transfer rate can be realized regardless of the transfer medium, belt end wear does not occur for a long time, excellent durability, and high It is possible to provide an intermediate transfer belt capable of forming an electrophotographic image with high image quality and a method for manufacturing the intermediate transfer belt.
Further, according to the present invention, there is provided a highly durable and high-quality image forming apparatus capable of maintaining high transfer performance not only initially but also for a long period of time regardless of the type and surface properties of the transfer medium. be able to.

FIG. 3 is a schematic diagram of a layer configuration example in an embodiment of an intermediate transfer belt in the present invention. The enlarged schematic diagram which observed the surface of the intermediate transfer belt in this invention from right above is shown. FIG. 2 shows a schematic diagram of a cross section of an intermediate transfer belt having a surface layer containing a plurality of particles. The schematic diagram of the apparatus for apply | coating the base layer and elastic layer in this invention is shown. The schematic diagram of the apparatus for apply | coating and fixing the spherical resin particle (powder particle) in this invention is shown. FIG. 3 is a schematic view of a main part for explaining an image forming apparatus equipped with an intermediate transfer belt according to the present invention. FIG. 3 is a schematic diagram of a main part showing a configuration example of an image forming apparatus in which a plurality of photosensitive drums are arranged in parallel along one intermediate transfer belt according to the present invention.

The intermediate transfer belt according to the present invention is an intermediate transfer belt to which a toner image in which a latent image formed on an image carrier is developed with toner is transferred. The intermediate transfer belt is laminated on the base layer 11. And an end protective layer 14 formed on the outermost surface on the elastic layer 12 side and on both ends of the intermediate transfer belt. The elastic layer 12 includes an elastic body and spherical resin particles 13. The spherical resin particles 13 are arranged in a plane direction on the surface of the elastic layer 12, and the end protective layer 14 contains a resin.
Next, the intermediate transfer belt 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.

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

(Layer structure of intermediate transfer belt)
The intermediate transfer belt of the present invention is an intermediate transfer belt type electrophotographic apparatus [so-called a plurality of color toner development images (toner images) sequentially formed on an image carrier (for example, a photosensitive drum)] Are seamless belts suitable for use in an apparatus of a type in which primary transfer is performed by sequentially superimposing the images on the recording medium, and the primary transfer image is collectively transferred to a recording medium (hereinafter also referred to as a transfer medium).

FIG. 1 shows a layer structure in an embodiment of an intermediate transfer belt suitably used in the present invention. However, it is not limited to this configuration.
In the present embodiment, a flexible elastic body is laminated on a rigid base layer 11 that can obtain a relatively flexible property, and spherical fine particles 13 are arranged on the outermost surface of the elastic body independently in the plane direction on the elastic body. (Embedded) forms a uniform uneven shape, and the elastic layer 12 is formed by the elastic body and the spherical fine particles 13. Further, end protection layers 14 made of resin are laminated on the outermost surfaces of both ends of the intermediate transfer belt. It is preferable that the spherical fine particles 13 in the present invention have almost no overlapping of the particles in the layer thickness direction and the complete embedding of the spherical fine particles 13 in the elastic layer 12.

  The intermediate transfer belt according to the present invention has a belt-like shape and is used while being stretched over a plurality of supports. In the present invention, both ends in the direction perpendicular to the belt surface with respect to the rotational direction of the intermediate transfer belt are referred to as both ends, and the outermost surface of the intermediate transfer belt on the elastic layer 12 side (the opposite side of the outermost surface on the base layer 11 side). The end protective layer 14 is provided on the outermost surface.

(Base layer 11)
First, the base layer 11 will be described. Examples of the material constituting the base layer 11 include a filler (or additive) that adjusts electrical resistance in the resin, that is, a so-called electrical resistance adjuster. Examples of such resins include fluorine resins such as PVDF (polyvinylidene fluoride) and ETFE (ethylene / tetrafluoroethylene copolymer), polyimide resins, and polyamideimide resins from the viewpoint of flame retardancy. In view of mechanical strength (high elasticity) and heat resistance, polyimide resin or polyamideimide resin is particularly preferable.

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

Examples of the electrical resistance adjusting agent include metal oxide, carbon black, ionic conductive agent, and 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 tetraalkyl ammonium salt, trialkyl benzyl ammonium salt, alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate, glycerol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine, and polyoxyethylene fatty acid. Alcohol ester, alkyl betaine, lithium perchlorate, etc. are mentioned, and these may be used in combination.
In addition, the electrical resistance adjusting agent in this invention is not limited to the said exemplary compound.

  In the method for producing an intermediate transfer belt of the present invention, the coating liquid contains a resin component, and further contains a dispersion aid, a reinforcing agent, a lubricant, a heat conductive agent, an antioxidant, and the like as necessary. May be.

The electrical resistance adjusting agent contained in the seamless belt suitably equipped as the intermediate transfer belt is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ in surface resistance and 1 × 10 ⁶ to 1 × in volume resistance. The amount is preferably 10 ¹² Ω · cm. However, in terms of mechanical strength, it is necessary to select and add an amount in a range where the molded film is brittle and does not easily break. 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 adjuster 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.

  In the case of carbon black, the content of the electrical resistance adjusting agent in the present invention is 10 to 25 wt%, preferably 15 to 20 wt% of the total solid content in the coating solution. 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%. If the content is less than the range of the respective electric resistance adjusting agents, the effect cannot be sufficiently obtained, and if the content is greater than the respective range, the mechanical strength of the intermediate transfer belt (seamless belt) decreases. This is not preferable for practical use.

  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 The method of measuring with a microscope (SEM) is mentioned.

(Elastic layer 12)
Next, the elastic layer 12 laminated on the base layer 11 will be described. The elastic layer 12 is laminated on the base layer 11, contains an elastic body and spherical resin particles 13 described later, and has an uneven shape on the surface. More specifically, the elastic layer 12 is formed by laminating an elastic body on the base layer 11 and further arranging spherical resin particles 13 in the surface direction on the surface of the elastic layer 12.

  As a material constituting the elastic body, materials such as general-purpose resins, elastomers, and rubbers can be used, but a material having sufficient flexibility (elasticity) is used in order to fully 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 the thermosetting elastomer 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. .

  A material capable of obtaining the desired performance is appropriately selected from the various elastomers and rubbers. In particular, it is preferable to select a soft material as much as possible in order to follow the surface state of a paper such as a resack paper having irregularities in the surface properties of the paper as a transfer medium (transfer material).

  In the present invention, in order to form spherical resin particles (spherical resin fine particle layer) on the surface of the elastomer material, a thermosetting material is preferable to a thermoplastic material. The thermosetting elastomer is more excellent in adhesiveness with the spherical resin particles due to the effect of the functional group contributing to the curing reaction, and can be reliably fixed. Vulcanized rubber is likewise preferred.

In the present invention, the material constituting the elastic body is most preferably acrylic rubber in terms of ozone resistance, flexibility, adhesion to spherical fine particles, imparting flame retardancy, and environmental stability.
Hereinafter, the acrylic rubber will be described.
In the present invention, the acrylic rubber constituting the elastic body in the rubber elastic layer 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 physical properties (especially compression set) and processability, so the carboxyl group crosslinking system is selected. 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 present invention, the acrylic rubber elastic layer may be used in combination with the crosslinking agent by further blending a crosslinking accelerator. 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.

  In addition to the selected materials, electrical resistance modifiers for adjusting electrical properties, flame retardants for obtaining flame retardancy, and materials such as antioxidants, reinforcing agents, fillers, vulcanization accelerators as necessary Is mixed appropriately.

  Furthermore, as the electric resistance adjusting agent for adjusting the electric characteristics, the above-described various materials can be applied. However, since carbon black, metal oxide, and the like impair flexibility, it is preferable to suppress the amount used, It is also effective to use an agent or a conductive polymer. Moreover, you may use these together.

Specifically, it is preferable to add 0.01 to 3 parts by weight of various perchlorates and ionic liquids with respect to 100 parts by weight of rubber. If the addition amount is less than 0.01 parts by weight, the effect of decreasing the resistivity cannot be obtained, and if the addition amount is more than 3 parts by weight, there is a high possibility that what is added to the belt surface will bloom or bleed. The resistance value of the elastic layer is preferably adjusted so that the surface resistance is 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ and the volume resistance is 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm. .

  On the other hand, the thickness of the elastic body is preferably about 200 μm to 2 mm, and more preferably 400 μm to 1000 μm. If the film thickness is thin, the followability to the surface properties of the transfer medium and the effect of reducing the transfer pressure are low, which is not preferable. If it is too thick, the film becomes heavier and tends to bend, resulting in instability in running performance, and cracks are likely to occur due to bending at the roller curvature portion for stretching the belt, which is not preferable. In addition, as a measuring method of the said thickness, a cross section can be measured with a scanning microscope (SEM).

(Spherical resin particles 13)
Next, the spherical resin particles 13 formed on the surface of the elastic body will be described. The spherical resin particles are preferably resin 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 spherical resin particles 13 are arranged in the surface direction on the surface of the elastic layer 12, thereby forming an uneven shape on the surface of the elastic body.

The material is not particularly limited, and 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. The resin particles referred to here include a rubber material. A structure in which the surface of spherical particles made of a rubber material is coated with a hard resin is also applicable. Moreover, it may be hollow or porous.
Among these resins, silicone resin particles are most preferred as those having a slipperiness and a high function capable of imparting releasability to toner and abrasion resistance.
It is preferable that the resin is a particle formed into a spherical shape by a polymerization method or the like using these resins. In the present invention, a particle closer to a true sphere is more preferable.

  The spherical resin particles 13 have a volume average particle size of 1.0 μm to 5.0 μm and are desirably monodisperse particles. 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 ± (average particle size × 0.5) μm or less. If the particle size is less than 1.0 μm, the effect of transfer performance by the particles cannot be sufficiently obtained. On the other hand, if the particle size is more than 5.0 μm, the surface roughness increases and the gap between the particles increases. Problems such as poor transfer and poor cleaning occur. 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.

  There is no restriction | limiting in particular as the spherical resin particle 13, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include silicone resin particles (Momentive Performance Materials, trade name “Tospearl 120”, trade name “Tospearl 145”, trade name “Tospearl 2000B”), acrylic resin particles (Sekisui Plastics Industries, Inc. Name "Techpolymer MBX-SS").

  Such spherical resin particles 13 can be easily and uniformly aligned by directly applying powder directly onto the elastic body. The timing for applying the spherical resin particles 13 to the surface of the elastic layer is not particularly limited, and can be any before or after vulcanization of the rubber.

(End protection layer 14)
Next, the end protection layer 14 formed on the both end surfaces of the elastic layer thus formed will be described. By forming the end protective layer 14, it is possible to obtain an effect of preventing the seal member or the like for preventing toner scattering in the cleaning unit and the intermediate transfer belt elastic layer from being rubbed and damaged.

  As the material constituting the end protection layer 14, a wide variety of general-purpose resin materials can be used. For example, acrylic resin, polyurethane resin, silicone resin, acrylic silicon resin, fluororesin, polyester resin, polyamide resin, Examples include, but are not limited to, polyimide resins, polyolefin resins, polyphenylene sulfide resins, polyetherimide resins, polycarbonate resins, amino resins, alkyd resins, epoxy resins, melamine resins, vinyl chloride resins, and phenol resins. Furthermore, two or more of these materials and other materials may be used in combination.

  A material capable of obtaining desired performance is appropriately selected from the various resin materials. In the present invention, an acrylic resin is most preferable from the viewpoints of adhesion to acrylic rubber suitably used as an elastic body, wear resistance, and scratch resistance. When a rubber or elastomer material used as an elastic body and a resin material that is inferior in adhesiveness are used for the edge protective layer, the edge protective layer will peel off if the intermediate transfer belt is used in an image forming apparatus for a long time. Occurs, and the effects of the present invention cannot be sufficiently obtained.

  The position at which the end protection layer 14 is provided is preferably kept from the end of the intermediate transfer belt at a position that does not reach the image forming portion on the intermediate transfer belt, in other words, outside the effective image area. If the area where the edge protection layer is provided is expanded to cover the image forming area, the electrical resistance and surface properties will be different between the area with and without the edge protection layer. May cause abnormal images. In addition, when an end protection layer is provided on the entire surface of the intermediate transfer belt, it is difficult to achieve both wear resistance, scratch resistance and toner transfer, and the end protection layer cannot follow the flexibility of the elastic layer. This is not preferable because cracks occur and adversely affect image quality. Specifically, it is preferable to have a width of about 0.5 cm to 3.0 cm, for example.

  The thickness of the end protective layer 14 is preferably 5.0 μm to 200.0 μm, and more preferably 5.0 μm to 50.0 μm. When the film thickness is thin, it is difficult to achieve the wear resistance and scratch resistance expected in the present invention over a long period of time, which is not preferable. On the other hand, if the film thickness is too thick, only the end of the intermediate transfer belt has a thick structure, and the running performance becomes unstable. The thickness can be measured by a method such as observing the cross section with a scanning microscope (SEM).

(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 intermediate transfer belt according to the present invention preferably adopts a form in which spherical resin particles having a uniform particle size are independently and orderly arranged, and it is preferable that the overlapping of the spherical resin particles is hardly observed. The diameter of the cross section of each spherical resin particle constituting the surface on the elastic body surface is preferably uniform, and specifically, it is preferable that the particle size distribution width is ± (average particle size × 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 even if this is not used, a particle having a certain particle size can be selectively formed on the surface of the elastic body by forming a surface. It is good also as a structure used as a diameter distribution width.

Regarding the projected area ratio between the exposed portion of the elastic body and the exposed portion of the spherical resin particles, the projected area ratio of the exposed portion of the spherical resin particles is preferably 60% or more, and more preferably 70% or more. If it is less than 60%, the area where the elastic body is exposed without being covered with the spherical resin particles becomes large, the toner and the elastic body come into contact with each other, and good toner transferability cannot be obtained. Mimability is significantly reduced.
The upper limit of the projected area ratio is 90.69% that can be taken with the hexagonal close-packed structure.

  In the present invention, the spherical resin particles take a form of being partially embedded in the elastic body, and the burying rate is preferably more than 50% and less than 100%, preferably 51% to 90%. It 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 burying in the elastic body having a diameter in the depth direction of the spherical resin particles. Here, the burial rate is over 50% for all spherical resin particles to 100%. It does not mean that it does not satisfy, but it is sufficient that the numerical value expressed by the average burial ratio when viewed from a certain visual field exceeds 50% and does not satisfy 100%. However, when the burial ratio is 50%, almost no particles completely embedded in the elastic body are observed in the cross-sectional observation by the electron microscope (the number% of the particles completely embedded in the elastic body is the total number of particles). (5% or less).

  In addition, the spherical resin particles 13 are arranged in a plane direction on the surface of the elastic layer 12, and the particles are preferably formed as a single layer in the thickness direction of the elastic layer 12 with respect to the elastic layer. As shown in FIG. 3, in the configuration including a plurality of particles in the thickness direction, the distribution of the spherical resin particles becomes uneven, and the electric characteristics of the belt surface are deteriorated due to the influence of the electric resistance value of the spherical resin particles. It becomes uniform and image distortion occurs. Specifically, the electrical resistance value in a portion where many spherical resin particles are present increases, a surface potential is generated due to residual charges, and surface potential variation occurs on the belt surface, and an image in an adjacent portion is generated. Image disturbance due to a difference in density becomes apparent.

(Method for manufacturing intermediate transfer belt)
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 a coating solution containing at least a resin component, that is, a coating solution containing the polyimide resin precursor or the polyamideimide resin precursor will be described.
The substrate made of polyimide resin or polyamideimide resin is coated on the surface of the cylindrical support (mold) with the precursor liquid by spiral coating with a nozzle or dispenser, or die coating with a wide die, or roll coating using a coating roll. It can be applied by, for example. Here, roll coating will be described. Coating can be performed by an apparatus as shown in FIG. A is a paint pan for storing the defoamed precursor liquid which is a paint, C is an application roller for continuously pumping up the paint B from the paint pan A, and D is a paint pump which is continuously pumped up. A regulating roller for adjusting the thickness with a gap between the coating roller C and a predetermined coating thickness, and E is a cylindrical support for transferring a coating (coating film) having a predetermined thickness from the coating roller C and attaching it. It is a body (mold).

  First, the precursor paint B, which has been sufficiently defoamed in advance, is poured into the paint pan A into the manufacturing apparatus described above. The viscosity of the paint is desirably adjusted to 0.5 to 10 Pa · s with an organic polar solvent (a well-known and conventional one can be used). Next, the paint pan A in which the paint B is poured into the lower part of the application roller C is approached and immersed in the paint B, and the paint B is attached to the surface of the application roller C at a slow peripheral speed of 10 to 100 mm / sec and pumped upward. To go. Thereafter, the thickness of the paint on the application roller C is adjusted by a regulating roller C which is installed on the upper side of the application roller C and can adjust an arbitrary gap with the application roller C. The thickness of the paint to be regulated is preferably about twice the thickness of the paint transferred to the cylindrical support E.

  Next, while the cylindrical support E is slowly rotated on the application roller C, it is brought close to the coating thickness of the application roller C or less. The coating material on the application roller is transferred onto the cylindrical support E that rotates in the same direction as the application roller C (the “clockwise direction” in the direction shown in FIG. 4). A paint having a predetermined film thickness is deposited on E.

  After application, the solvent in the coating film is evaporated at a temperature of about 80 to 150 ° C. while gradually raising the temperature while rotating the cylindrical support E. 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 the polyimide resin precursor or polyamide-imide resin precursor.

  After sufficiently cooling, the elastic body is subsequently laminated. The elastic layer can be manufactured by using a rubber paint in which rubber is dissolved in an organic solvent, coating and forming on the base layer 11, and then drying and vulcanizing the solvent. As the coating molding method, as with the base layer 11, existing coating methods such as spiral coating, die coating, and roll coating can be applied. However, in order to improve uneven transferability, the thickness of the elastic body should be increased. As a coating method for forming a thick film, die coating and spiral coating are excellent. Here, the spiral coating will be described. While rotating the base layer in the circumferential direction and continuously supplying rubber paint with a round or wide nozzle, the nozzle is moved in the axial direction of the base layer 11 and the paint is spirally applied on the base layer 11 To do. The paint applied spirally on the base layer 11 is dried while being leveled by maintaining a predetermined rotation speed and drying temperature.

  Then, when sufficiently leveled, as shown in FIG. 5, a powder supply device 35 and a pressing member 33 are installed, and spherical particles (resin particles) 34 are uniformly applied to the surface from the powder supply device 35 while rotating. The spherical particles 34 sprayed on the surface are pressed by the pressing member 33 at a constant pressure. The pressing member 33 removes excess particles 34 while burying the particles 34 in a belt 32 formed by applying a base layer supported by the mold drum 31 and an elastic body. In the present invention, in particular, since monodispersed spherical particles are used, 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 adjustment of the burying rate of the particles 13 in the elastic layer 12 may be possible by other methods, but can be easily achieved by, for example, adjusting the pressing force of the pressing member 33. For example, although it depends on the viscosity of the casting coating liquid, the resin content, the amount of solvent used, the resin material, etc., as a guideline, the pressing force is 10 mN at a viscosity of 100 to 100,000 mPa · s of the casting coating liquid. By setting the ratio in the range of / cm to 1000 mN / cm, the above-mentioned 50% <buried ratio <100% can be achieved relatively easily. After forming a uniform particle layer, it is cured by heating at a predetermined temperature for a predetermined time to form an elastic layer.

  Finally, the end protective layer 14 is formed. After covering the portion where the end protection layer 14 is not formed with a masking film, the coating liquid containing at least the above-described component of the end protection layer is sprayed or sprayed while slowly rotating the cylindrical metal mold. 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. Then, when it has been sufficiently leveled, it is dried or cured by heating at a predetermined temperature and a predetermined time while rotating to form an end protective layer. After sufficiently cooling, the masking film covering the portion where the end protection layer is not formed is peeled off and detached from the mold together with the base material layer to obtain a desired seamless belt.

The method for measuring the burying rate of the spherical 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 can be measured with 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.

  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 particles and the occupied area ratio. The resistance can be measured by using a commercially available measuring instrument, for example, by using Hiresta manufactured by Dia Instruments.

  For example, the seamless belt manufactured by the above-described method performs primary transfer by sequentially superimposing a plurality of color toner developed images sequentially formed on an image carrier on an intermediate transfer belt, and the primary transfer image is transferred. An electrophotographic apparatus (image forming apparatus) that can be suitably used as an intermediate transfer belt of an electrophotographic apparatus of a so-called intermediate transfer type that performs secondary transfer collectively onto a medium (recording medium) and forms a high-quality image. it can.

  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. 6 is a schematic view of a main part for explaining an image forming apparatus equipped with an intermediate transfer belt according to the present invention.
An intermediate transfer unit 500 shown in FIG. 6 includes an intermediate transfer belt 501 that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt 501, a secondary transfer bias roller 605 that is a secondary transfer charge applying unit of the secondary transfer unit 600, a belt cleaning blade 504 that is an intermediate transfer member cleaning unit, and a lubricant for a lubricant application unit. A lubricant application brush 505 or the like that is an application member is disposed so as to face each other.

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 blade 504, which may be difficult to arrange. A position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt 501. An optical sensor 514 serving as a mark detection sensor is provided at a position between the primary transfer bias roller 507 and the belt driving roller 508 where the intermediate transfer belt 501 is bridged.
Further, a neutralizing roller 70 is provided on the inner peripheral surface of the intermediate transfer belt 501 to remove the accumulated charges, and an earth roller 80 is provided and grounded.

  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 (clockwise direction) by a belt driving roller 508 that is driven to rotate clockwise in FIG. 6 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. In the present invention, the intermediate transfer belt according to the present invention described above is used. As a result, durability is improved and 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 (image carrier) 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 medium to be transferred (recording medium), between the portion of the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510. In addition, a transfer bias of a predetermined current is applied by a secondary transfer power source 802 controlled by constant current.

  The registration roller 610 feeds the transfer paper P, which is a transfer medium (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 counterclockwise as indicated by an arrow by a drive motor (not shown), and on the photosensitive drum 200, 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. 6, 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 corresponding 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. The negatively charged Bk toner on the developing roller of the Bk developing device (developing means) 231K comes into contact with the Bk electrostatic latent image, so that the toner adheres to the remaining portion of the photosensitive drum 200. In other words, toner is attracted to a portion having no charge, that is, an exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

  The Bk toner image formed on the photosensitive drum 200 in this 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 the C image data by the color scanner starts at a predetermined timing (or may be read simultaneously with the Bk image). A C electrostatic latent image is formed on the surface of the photosensitive drum 200 by writing the laser beam with the C image data.

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.
At this time, the potential on the photosensitive drum 200 after exposure by the laser beam L is measured by the potential sensor 204, and the toner density on the photosensitive drum 200 after development by the developing machine 231 is measured by the image density sensor 205. The measurement result is fed back.

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 (toner image 513; full-color 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 sheet P passes through the secondary transfer portion, the transfer bias generated by the voltage applied to the secondary transfer bias roller (transfer means) 605 by the secondary transfer power source 802 causes 4 on the intermediate transfer belt 501. The color superimposed toner image is 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. 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 charged by the charging charger 503 and then cleaned by the belt cleaning blade 504. The belt cleaning blade 504 is configured to be brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by a cleaning member separating and contacting mechanism (not shown).

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

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

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

In the above-described embodiment, the copying machine including only one photosensitive drum 200 has been described. However, the present invention includes a plurality of photosensitive drums as shown in an exemplary configuration 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. 7 shows a configuration of a four-drum digital color printer including four photosensitive drums 21BK, 21Y, 21M, and 21C for forming toner images of four different colors (black, yellow, magenta, and cyan). An example is shown.

  In FIG. 7, the printer main 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 (organic 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 driven by a driving roller 26 and other rollers. It is stretched and driven in the clockwise direction by the driving roller 26, and the toner images of the respective colors formed on the respective photoconductors are sequentially superimposed and transferred. A neutralization roller 70 is provided on the inner peripheral surface of the intermediate transfer belt 22 to neutralize the accumulated charges.

  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.

[Example 1]
A base layer coating solution was prepared as follows, and a seamless belt base layer was produced using this coating solution.

<Preparation of base layer coating solution>
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; manufactured by Ube Industries) 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.

<Manufacture of seamless belts>
Next, a metal cylindrical support whose outer surface having an outer diameter of 340 mm and a length of 360 mm was roughened by blasting was used as a mold and attached to a roll coater. Next, the coating liquid A for base layer 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. 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, and then rotated. While maintaining, 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. Thereafter, this was introduced into a heating furnace (baking furnace) capable of high-temperature treatment, heated up to 320 ° C. stepwise, and heat-treated (baked) for 60 minutes to form a base layer having a thickness of 80 μm.

<Production of elastic layer on base layer>
Each constituent material shown below was mixed and sufficiently kneaded using a biaxial kneader to prepare a rubber composition.

<Elastic layer material>
・ Acrylic rubber Nipol AR12 (Nippon ZEON Co., Ltd.) 100 parts by weight ・ Stearic acid Bead stearic acid Tsubaki (NOF Corporation) 1 part by weight ・ Red phosphorus Nova Excel 140F (Rin Chemical Industry Co., Ltd.) 10 parts by weight ・ Aluminum hydroxide Heidilite H42M (Showa Denko Co., Ltd.) 60 parts by weight / crosslinking agent Diak. No1 (hexamethylenediamine carbamate)
(DuPont Dow Elastomer Japan) 0.6 parts by weight / crosslinking accelerator VULCOFAC ACT55
(Salt of 70% 1,8-diazabicyclo (5,4,0) undecene-7 and dibasic acid, 30% amorphous silica) (Safic alca)
1 part by weight / conductive agent QAP-01 (tetrabutylammonium perchlorate)
(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%. While rotating the cylindrical support on which the prepared polyimide base layer was formed, the prepared rubber solution was moved to the support axis method while continuously discharging rubber paint from the nozzle onto the polyimide base layer. Coated. The coating amount was such that the final film thickness was 500 μm.

  When the predetermined amount has been poured and the coating has spread evenly, using the method of FIG. 5, as the spherical resin particles, silicone resin particles (Tospearl 130 (volume average particle size 3.0 μm product); Momentive Performance Material) was evenly applied to the surface, and the pressing member of the polyurethane rubber blade was pressed to fix it to the elastic layer. At this time, the pressing force of the pressing member was set to 100 mN / cm.

  After finishing the entire surface of the belt, the cylindrical support coated with rubber paint is put into a hot air circulating dryer while rotating as it is, and the temperature is raised to 90 ° C. at a temperature rising rate of 4 ° C./min. Heated for 30 minutes. Then, it heated up to 170 degreeC with the temperature increase rate of 4 degree-C / min, and heat-processed for 60 minutes. After stopping the heating, it was gradually cooled to room temperature.

<Preparation of edge protective layer>
Subsequently, after covering the elastic layer prepared above with a masking film so that both ends are exposed by 2.0 cm, an acrylic resin paint (ACRYDIC A-405; DIC Corporation) is applied by spray coating. It was applied uniformly while rotating. Note that 2.0 cm from both ends is a width that does not enter the effective image area of the intermediate transfer belt in the image forming apparatus used in this embodiment. The coating amount was such that the final film thickness was 20.0 μm. Thereafter, the mold was rotated as it was, and then charged into a hot air circulating dryer, and heated at 150 ° C. for 30 minutes. After sufficiently cooling, the masking film was peeled off and removed from the mold to obtain an intermediate transfer belt A.

[Example 2]
An intermediate transfer belt B was obtained in the same manner as in Example 1 except that the thickness of the end protective layer was 3.0 μm.

[Example 3]
An intermediate transfer belt C was obtained in the same manner as in Example 1 except that <Preparation of edge protective layer> in Example 1 was changed as follows.
<Preparation of edge protective layer>
Subsequently, the elastic layer produced above was covered with a masking film so that both ends were exposed by 2.0 cm, and then the mold was rotated by spray coating with melamine resin paint (Organeo; Nippon Paint Co., Ltd.). It was applied evenly. Note that 2.0 cm from both ends is a width that does not enter the effective image area of the intermediate transfer belt in the image forming apparatus used in this embodiment. The coating amount was such that the final film thickness was 20.0 μm. Thereafter, the mold was rotated as it was, and was put into a hot air circulating dryer and heated at 130 ° C. for 30 minutes. After sufficiently cooling, the masking film was peeled off and removed from the mold to obtain an intermediate transfer belt C.

[Example 4]
An intermediate transfer belt D was obtained in the same manner as in Example 1 except that <elastic layer constituent material> in Example 1 was changed to the following materials.
<Elastic layer material>
・ Hydrogenated nitrile rubber Zetpol 2020L (Nippon ZEON Co., Ltd.) 100 parts by weight ・ Stearic acid Bead stearic acid Tsubaki (NOF Co., Ltd.) 1 part by weight 2 types of zinc white (Shodo Chemical Industry) 5 parts by weight, vulcanization accelerator Noxeller TS (tetramethylthiuram monosulfide)
(Ouchi Shinsei Chemical Co., Ltd.) 0.5 parts by weight, red phosphorus Nova Excel 140F (Rin Chemical Industry Co., Ltd.) 10 parts by weight, aluminum hydroxide Heidilite H42M (Showa Denko) 40 parts by weight

[Example 5]
An intermediate transfer belt E was obtained in the same manner as in Example 1, except that <elastic layer constituent material> and <production of end protective layer> in Example 1 were changed as follows.

<Elastic layer material>
・ Hydrogenated nitrile rubber Zetpol 2020L (Nippon ZEON Co., Ltd.) 100 parts by weight ・ Stearic acid Bead stearic acid Tsubaki (NOF Co., Ltd.) 1 part by weight 2 types of zinc white (Shodo Chemical Industry) 5 parts by weight, vulcanization accelerator Noxeller TS (tetramethylthiuram monosulfide)
(Ouchi Shinsei Chemical Co., Ltd.) 0.5 parts by weight, red phosphorus Nova Excel 140F (Rin Chemical Industry Co., Ltd.) 10 parts by weight, aluminum hydroxide Heidilite H42M (Showa Denko Co., Ltd.) 40 parts by weight

<Preparation of edge protective layer>
Subsequently, the elastic layer produced above was covered with a masking film so that both ends were exposed by 2.0 cm, and then the mold was rotated by spray coating with melamine resin paint (Organeo; Nippon Paint Co., Ltd.). It was applied evenly. Note that 2.0 cm from both ends is a width that does not enter the effective image area of the intermediate transfer belt in the image forming apparatus used in this embodiment. The coating amount was such that the final film thickness was 20.0 μm. Thereafter, the mold was rotated as it was, and was put into a hot air circulating dryer and heated at 130 ° C. for 30 minutes. After sufficiently cooling, the masking film was peeled off and removed from the mold to obtain an intermediate transfer belt E.

[Example 6]
In the same manner as in Example 1 except that the spherical resin particles in Example 1 were changed to acrylic spherical fine particles (Sekisui Plastics Industry, trade name “Techpolymer MBX-SS” (volume average particle size 1 μm product)), A transfer belt F was obtained.

[Comparative Example 1]
An intermediate transfer belt G was manufactured in the same manner as in Example 1 except that the end protective layer was not formed.

[Comparative Example 2]
In Example 1, the intermediate transfer belt H was manufactured in the same manner as in the step of forming the end protective layer except that the elastic layer was not covered with the king film and the protective layer was formed on the entire surface of the belt.

  The intermediate transfer belts A to H of each of the above examples and comparative examples are mounted on the image forming apparatus of FIG. 7, and the image quality on uneven paper (rezac 260 kg paper) (toner transferability of cyan and magenta two-color blue solid) Was performed by visual judgment. In the judgment, ◎ is very good, が is the actual usable level, △ is the density of the concave portion is low, or density unevenness, white spots, image distortion, etc. occur due to location, and x is unusable. Thereafter, 200,000 sheets were continuously fed, and image quality and belt surface observation were performed every 100,000 sheets.

  Further, the rank of the intermediate transfer belt end worn state after continuous 200,000 sheets was visually judged. Judgment is that ◎ is almost unchanged from the initial stage, ◯ is a practical level, Δ is partially damaged and the protective layer is peeled off, but the image quality is not affected, and × is unusable.

  The results of the above evaluation are shown in Table 1 below.

  Examples 1 to 6 exhibited excellent performance both at the initial stage and after output of 200,000 sheets. On the other hand, in Comparative Example 1 in which the protective layer was not formed at the end portion, although excellent image quality was initially obtained, the elastic layers at both ends of the belt were worn violently as it was used over a long period of time. As a result, the elastic layer shavings adhere to the photoconductor and abnormal images such as white spots occur, or the belt running performance becomes unstable and distorted images occur. It became. Further, in Comparative Example 2 in which the protective layer was formed on the entire belt surface, although the edge protection effect was obtained, the protective layer with poor toner transferability was formed even in the effective image area, so that it was sufficient from the initial stage. Image quality could not be obtained.

  As described above, by adopting the configuration of the present invention, a high-quality electrophotographic apparatus that can realize a high transfer rate regardless of a transfer medium, and that does not cause belt end wear over a long period of time and has excellent durability. It is possible to obtain an intermediate transfer belt for realization.

(Reference numerals in FIGS. 1 to 3)
DESCRIPTION OF SYMBOLS 11 Base layer 12 Elastic layer 13 Spherical resin particle 14 End part protective layer (code | symbol of FIG. 4)
A Paint pan B Paint C Coating roll D Regulating roll E Cylindrical support (mold)
(Reference in FIG. 5)
31 Mold drum 32 Belt 33 coated with base layer and elastic layer Pressing member 34 Resin particle 35 Powder coating device (reference numeral in FIG. 6)
P Transfer paper L Laser light 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photosensitive drum cleaning device 202 Static elimination lamp 203 Charging charger 204 Potential sensor 205 Image density sensor 210 Belt conveying device 230 Revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C developing machine 231M M developing machine 270 fixing device 271 and 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 502 toner seal member 503 charging charger 504 belt cleaning blade 505 lubricant application brush 506 lubricant 507 primary transfer bias roller 508 Belt drive roller 509 Belt tension roller 510 Secondary transfer counter roller 511 Cleaning counter roller 512 Feedback current detection sensor 513 Toner image 514 Optical sensor 600 Secondary transfer unit 601 Transfer paper guide plate 605 Secondary transfer bias roller 606 Transfer paper neutralization charger 608 Cleaning blade 610 Registration roller 801 Primary transfer power source 802 Secondary transfer power source (reference numeral in FIG. 7) )
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 conveyance belt 60 Secondary transfer bias roller 70 Static elimination roller

JP 2009-300490 A JP 2009-48032 PR JP 2002-162767 A Japanese Laid-Open Patent Publication No. 2004-354716 JP 2007-328165 A JP 2009-75154 A

Claims (8)

An intermediate transfer belt to which a toner image in which a latent image formed on an image carrier is developed with toner is transferred;
A base layer, an elastic layer laminated on the base layer, and an end protection layer formed on the outermost surface on the elastic layer side and at both ends of the intermediate transfer belt,
The elastic layer contains an elastic body and spherical resin particles,
The spherical resin particles are arranged in a plane direction on the surface of the elastic layer,
The intermediate transfer belt, wherein the end protective layer contains a resin.   The intermediate transfer belt according to claim 1, wherein the end protection layer is formed outside an effective image area of the intermediate transfer belt.   The intermediate transfer belt according to claim 1, wherein the end protective layer includes an acrylic resin.   The intermediate transfer belt according to claim 1, wherein the end protective layer has a thickness of 5.0 μm or more and 200.0 μm or less.   The intermediate transfer belt according to claim 1, wherein the elastic body includes acrylic rubber. An image carrier capable of carrying a toner image in which the latent image is formed and the latent image is developed with toner;
Developing means for developing a latent image formed on the image carrier with toner to form a toner image;
An intermediate transfer belt on which a toner image developed by the developing means is primarily transferred;
A transfer means for secondary transfer of the toner image carried on the intermediate transfer belt to a recording medium,
An image forming apparatus, wherein the intermediate transfer belt is the intermediate transfer belt according to claim 1. Full color image formation is possible,
The image carrier and the developing means are provided for each color,
The image forming apparatus according to claim 6, wherein the image carrier is disposed along the intermediate transfer belt. A manufacturing method for manufacturing the intermediate transfer belt according to any one of claims 1 to 5,
Forming the base layer;
Forming the elastic layer;
Applying the spherical resin particles uniformly and dry onto the elastic layer;
Forming the spherical resin particles uniformly by arranging and embedding the spherical resin particles; and
And a step of forming the end protective layer. A method of manufacturing an intermediate transfer belt, comprising: