JP2013092668A - Intermediate transfer belt, image forming apparatus, and manufacturing method of intermediate transfer belt - Google Patents

Abstract

An intermediate transfer belt excellent in transferability to a paper type having surface irregularities and having excellent durability without being worn from the side surfaces of both ends of the belt for a long time, and the intermediate transfer belt are used. An intermediate transfer type image forming apparatus suitable for full-color image formation and a method for manufacturing the intermediate transfer belt are provided.
A toner image in which a latent image formed on an image carrier is developed with toner is primarily transferred, and a transfer residue remaining after the toner image is secondarily transferred to a recording medium. An intermediate transfer belt in which toner is cleaned by a cleaning member having a seal member for preventing toner scattering, and includes a base layer 11 and an elastic layer 12 laminated on the base layer 11, and the elastic layer 12 The side surface is characterized by being subjected to a surface treatment.
[Selection] Figure 3

Description

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

  By the way, in the intermediate transfer belt provided with the rubber elastic layer, the rubber component constituting the elastic layer is exposed on the side surface of the rubber elastic layer. This rubber component is inferior in mechanical characteristics and thermal characteristics as compared with the surface of the intermediate transfer belt subjected to surface treatment. Therefore, when an object comes into contact with the side surface of the rubber elastic layer that has not been subjected to surface treatment and friction occurs, the surface is gradually scraped. In particular, the sealing member is installed at both ends of the intermediate transfer belt in the cleaning member so that the toner on the intermediate transfer belt is not scattered, but it is understood that the rubber elastic layer is worn from the side by friction with the sealing material. ing. In addition, the scraped rubber elastic layer component adheres to the photoconductor and causes a blank image, or the paper is soiled directly, or the edge portion is scraped, resulting in unstable running of the belt and distortion of the image. Was.

In Patent Document 1, a water-emulsion system is formed by dipping on both surfaces and end surfaces of both ends in the axial direction of the belt base material in order to suppress breakage from the end portions due to long-time rotation use in a state where tension is applied. It has been proposed to cover the reinforcing material to a uniform thickness.
Patent Document 2 proposes that a resin reinforcing material extending from the outer peripheral surface to the end surface along the circumferential direction is provided at the end in the axial direction of the endless resin belt main body.
However, there is no description regarding the intermediate transfer belt having the elastic layer, and the effect of end reinforcement is not clear. Also, there is no description regarding the protection of the side face by using silica fine particles.

Patent Document 3 proposes a means for reinforcing both ends by sticking Teflon (registered trademark) or polyethylene-based tape material to the belt ends at both ends.
However, the end surface on the side of the intermediate transfer belt is not reinforced, and in the case of an elastic material that is easily rubbed, there is a problem that the long life and high durability required for recent electrophotographic apparatuses cannot be obtained. It was.

In Patent Document 4, it is proposed not to affix the meandering rib member to the inner peripheral surface of the belt base, but to place the guide member against the belt end surface and affix the rib member thereon. . As a result, the rib member can be accurately arranged at a predetermined position, and the guide member can be firmly fixed. Further, it has been reported that since the abutting area with respect to the end face is secured in the bonding, the positioning accuracy can be improved, the bonding of the guide member can be simplified, and the breakage can be prevented.
However, Patent Document 4 does not describe an intermediate transfer belt having an elastic layer, and the effect on the abrasion of the elastic layer is not clear.

In Patent Document 5, as a method for protecting the surface of the elastic intermediate transfer belt, it is proposed to form a layer with a material having affinity for the hydrophobized fine particles. In these, the particle | grains of a very small particle diameter are used preferably.
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. Moreover, since the side surface is not protected, there is a concern that the side surface is worn.

  The present invention has been made in view of the above prior art, has excellent transferability to a paper type with surface irregularities, and has excellent durability without being worn from the side surfaces of both ends of the belt for a long period of time. An object of the present invention is to provide an intermediate transfer belt, an intermediate transfer type image forming apparatus suitable for full-color image formation using the intermediate transfer belt, and a method of manufacturing the intermediate transfer belt.

In order to solve the above problems, an intermediate transfer belt according to the present invention is a toner image in which a latent image formed on an image carrier is developed with toner, and the toner image is recorded. An intermediate transfer belt in which transfer residual toner remaining after secondary transfer to a medium is cleaned by a cleaning member having a seal member for preventing toner scattering, and a base layer and an elastic layer laminated on the base layer The side surface of the elastic layer is subjected to a surface treatment.
Further, in order to solve the above problems, a method for producing an intermediate transfer belt according to the present invention is a method for producing the above intermediate transfer belt,
(1): forming the base layer;
(2): forming the elastic layer on the base layer;
(3): cutting both ends so that the base layer and the elastic layer obtained in (2) have a predetermined width;
(4): a step of performing a surface treatment on the side surface of the elastic layer after cutting according to (3),
It is characterized by having.
Further, 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 an 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.

  According to the present invention, there is no end wear, high durability, high transfer performance regardless of the type and surface shape of the transfer medium, and high image quality can be achieved by mounting on an electrophotographic image forming apparatus. An intermediate transfer belt, an image forming apparatus using the intermediate transfer belt, and a method for manufacturing the intermediate transfer belt can be provided.

The schematic diagram of the layer structural example (The surface treatment of the elastic layer 12 is abbreviate | omitting illustration) in one Embodiment of the intermediate transfer belt in this invention is shown. 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. 1 is a schematic cross-sectional view illustrating a configuration in an embodiment of an intermediate transfer belt according to the present invention. FIG. 6 is a schematic cross-sectional view showing a configuration in another embodiment of an intermediate transfer belt in the present invention. FIG. 6 is a schematic cross-sectional view showing a configuration in another embodiment of an intermediate transfer belt in the present invention. FIG. 6 is a schematic cross-sectional view showing a configuration in another embodiment of an intermediate transfer belt in the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of an intermediate transfer belt as a reference example. The schematic diagram of the apparatus for apply | coating and fixing the spherical fine 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 such that a toner image obtained by developing a latent image formed on an image carrier with toner is primarily transferred, and the toner image is secondarily transferred to a recording medium. An intermediate transfer belt in which a transfer residual toner remaining afterward is cleaned by a cleaning member having a seal member for preventing toner scattering, and includes a base layer 11 and an elastic layer 12 laminated on the base layer 11. The side surface of the elastic layer 12 is surface-treated.

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.

(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 this embodiment, a flexible elastic layer 12 is laminated on a rigid base layer 11 that can be relatively flexible, and a surface layer 13 is formed on the outermost surface (the outermost surface opposite to the base layer 11) as necessary. Are stacked.
Although not shown in the drawings as will be described later, the side surface of the elastic layer 12 (the surface to be bonded to the base layer 11 is the main surface, and the surface is perpendicular to the main surface) is subjected to surface treatment. Has been.

(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 is preferably equipped as an intermediate transfer belt is preferably 1 × 10 ⁸ ~1 × in surface resistance ^{10 13 Ω / □, 1 ×} 10 8 ~1 × volume resistivity The amount is preferably 10 ¹¹ 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 each of the electric resistance adjusting agents, 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 (seamless belt) is lowered, which is not preferable in actual 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.
As the material constituting the elastic layer, materials such as general-purpose resins, elastomers, and rubbers can be used. However, a material having sufficient flexibility (elasticity) to sufficiently exhibit the effects of the present invention is used. 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 the present invention, the material constituting the elastic layer is most preferably acrylic rubber from the viewpoints 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 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.

The resistivity control required for the intermediate transfer belt requires 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 by weight of various perchlorates and ionic liquids with respect to 100 parts by weight of rubber. If the addition amount of the ionic conductive agent is less than 0.01 parts by weight, the effect of reducing the resistivity cannot be obtained, and if the addition amount is more than 3 parts by weight, the possibility that the conductive agent blooms or bleeds to the surface of the intermediate transfer belt becomes high. End up. 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 ⁷ to 1 × 10 ¹² Ω · cm. .

  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 less than 400 μm, the image quality for a paper type having surface irregularities will be insufficient. If it exceeds 1000 μm, the film will become heavier, bend easily, the warpage will become large, the running performance will become unstable, and cracks will occur due to bending at the roller curvature for stretching the belt It is not preferable because it is easy to do. In addition, as a measuring method of the said thickness, a cross section can be measured with a scanning microscope (SEM).

  In addition, the length in the width direction of the intermediate transfer belt is preferably 300 mm or more from the viewpoint of increasing the speed, image quality, and durability of recent electrophotography.

(Surface layer 13)
Next, the surface layer 13 laminated on the elastic layer 12 will be described. It has been found that toner transferability and durability can be improved by applying some surface treatment to the surface of the elastic layer 12.

  The material is not particularly limited, and a coating method mainly comprising a material such as resin, elastomer or rubber can be used.

  Examples of the resin material include acrylic resin, melamine resin, polyamide resin, polyester resin, silicone resin, and fluorine resin.

  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. .

(Spherical fine particles 14)
Next, the spherical fine particles 14 will be described.
Spherical fine particles may also be used as a coating material for the intermediate transfer belt. Here, an example in which spherical fine particles are used for the surface layer 13 on the elastic layer 12 as shown in FIG. 2 will be described.
The spherical fine particles are preferably spherical 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 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 fine particles 14 have a volume average particle size of 1.0 μm to 5.0 μm and are preferably 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 spherical fine particle 14, 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").

  The timing at which the spherical fine particles 14 are applied to the surface of the elastic layer is not particularly limited, and can be either before or after rubber vulcanization.

(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 preferably takes a form in which spherical fine particles having a uniform particle diameter are arranged in an orderly manner, and it is preferred that little overlap between the spherical fine particles is observed. It is preferable that the diameter of the cross section of each spherical fine particle constituting the surface on the surface of the intermediate transfer belt is 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 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 width.

The area occupied by the spherical fine particles 14 on the surface of the intermediate transfer belt is preferably 60% or more, and more preferably 70% or more. When the occupied area ratio is less than 60%, the resin part (the elastic layer 12 and the surface layer 13) is not covered with the spherical fine particles 14 and the exposed part of the resin part (elastic layer 12 and surface layer 13) is too much, and the toner and the rubber are in contact with each other. I can't get it.
The upper limit of the occupied area ratio is 90.69% that can be taken in the hexagonal close-packed structure, and it is more preferable that the upper limit is closer to this upper limit value.

  In the present invention, the spherical fine particles 14 take a form of being partially embedded in the elastic layer, 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 at which the spherical fine particles are buried in the elastic layer 12 and the surface layer 13 having a diameter in the depth direction. It does not mean that it is less than%, and it is sufficient that the numerical value expressed by the average burial rate when viewed from a certain visual field exceeds 50% and does not reach 100%. However, when the burial ratio is 50%, in the cross-sectional observation by the electron microscope, the particles completely buried in the elastic layer 12 and the surface layer 13 are hardly observed (they are completely buried in the elastic layer 12 and the surface layer 13). The number% of the particles is 5% or less of the whole particles).

  Regarding the surface treatment of the elastic layer 12, in addition to the coating method using resin or spherical fine particles, a treatment by a method such as plasma treatment, chlorination treatment, or UV treatment may be used.

<Intermediate transfer belt whose side surface is subjected to surface treatment>
Next, the example which performed the surface treatment to the end surface of the said elastic layer 12 is demonstrated. When the surface layer 13 is processed, the processing on the side surface of the elastic layer 12 may be insufficient because the processing on the side surface of the elastic layer 12 is not performed directly. Moreover, after finishing the surface treatment in the manufacturing process, the side face of the elastic layer is completely exposed by cutting to adjust the width of the belt. Accordingly, it is necessary to perform some treatment on the portion where the elastic layer 12 is exposed.

  It is preferable to apply the silicone spherical fine particles 14 to the side surface of the elastic layer so that the rubber on the side surface of the elastic layer is not exposed. FIG. 3 is a schematic sectional view of an intermediate transfer belt in which silicone spherical fine particles are coated on the side of the elastic layer. The presence or absence of the spherical fine particles 14 can be confirmed by observing with a scanning microscope (SEM).

  As a method for treating the side surface of the elastic layer, it is preferable to coat the end surface with a resin. A coating material with excellent heat resistance and wear resistance should be selected. FIG. 4 is a schematic cross-sectional view of an intermediate transfer belt in which a resin protective layer 15 is coated on the side surface of the elastic layer. In addition, application | coating of a coating material can be confirmed by infrared spectroscopy (ATR * FT-IR).

  In order to prevent the rubber on the side of the elastic layer from being exposed, it is preferable to apply the silicone spherical fine particles 14 to the side of the elastic layer and also apply the silicone spherical fine particles 14 to the surface of the intermediate transfer belt. FIG. 5 is a schematic cross-sectional view of an intermediate transfer belt in which silicone spherical fine particles are coated on the side surface of the elastic layer and the surface of the intermediate transfer belt. The presence or absence of the spherical fine particles 14 can be confirmed by observing with a scanning microscope (SEM).

  As a surface treatment method for the side surface of the elastic layer, it is preferable to coat the surface with a resin containing a UV curing agent. As the coating material, it is preferable to select a coating material having excellent heat resistance and wear resistance after UV curing. FIG. 6 shows a schematic cross-sectional view of an intermediate transfer belt in which the side surface of the elastic layer is coated with a resin protective layer 15 containing a UV curing agent. In addition, application | coating of a coating material can be confirmed by infrared spectroscopy (ATR * FT-IR).

  The side of the elastic layer is preferably protected with a tape so that the rubber on the side of the elastic layer is not exposed. FIG. 7 is a schematic cross-sectional view of the intermediate transfer belt in which the reinforcing tape 16 is installed on the side surface of the elastic layer and part of the surface and part of the back surface of the intermediate transfer belt. The installation range of the reinforcing tape 16 is not limited to the side surface, and may extend to the front surface or the back surface as long as it is outside the effective image area of the belt. It is recommended to select one that has excellent heat resistance and wear resistance.

(Resin protective layer 15)
The resin protective layer 15 is preferably made of an acrylic resin, methacrylic resin, urethane resin, melamine resin, polyamide resin, polyester resin, polyether resin, polyvinyl ether resin, polyolefin resin, epoxy resin, silicone resin, fluorine resin, or the like. Is mentioned. Preferably, a fluororesin or silicone resin excellent in low friction coefficient and mechanical properties is desirable.
Fluoropolymers are commercially available, such as Lumiflon (Asahi Glass Co., Ltd.) and Neoflon (Daikin Industries Co., Ltd.).
Further, the ultraviolet curable resin contains at least one of ultraviolet curable monomers, oligomers, and prepolymers, and these resin materials are preferably acrylic resin, methacrylic resin, urethane resin, polyester resin, epoxy resin, polyether resin, A polyvinyl ether resin etc. are mentioned. It is sufficient if a photopolymerization initiator is contained in the resin, and curing of the resin is started by irradiation with ultraviolet rays. Examples of the photopolymerization initiator include benzoxanthone, thioxanthone series including chlorothioxanthone and isopropylthioxanthone, benzylmethyl ketal, α-hydroxyketone, α-aminoketone and the like. As the resin, an acrylic resin or vinyl ether resin excellent in handling property, light transmittance, and mechanical properties is preferable. Examples of commercially available UV curable resins include Unidic RC29-117 (manufactured by DIC Corporation).

(Reinforcing tape 16)
The material of the reinforcing tape 16 is preferably a resin material such as polyester, acrylic, polyamide, epoxy, silicon, chlorine, or fluorine,
Preferably, a fluorine-based or polyimide-based resin material having excellent heat resistance and mechanical resistance is desirable.
As a polyimide tape, there exist a Kapton tape, a double-sided Kapton insulating tape, etc. as a commercial item.

(Method for manufacturing intermediate transfer belt)
Next, an example of a method for producing the intermediate transfer 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.

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 elastic layer 12 is subsequently laminated.

  The base layer 11 made of polyimide resin or polyamide-imide resin used a spiral coating by a nozzle or a dispenser, a die coating by a wide die, or a coating roll on the surface of a cylindrical support (mold). It can be applied by roll coating or the like.

The elastic layer 12 can be manufactured by coating and forming on the base layer 11 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 11, existing coating methods such as spiral coating, die coating, and roll coating can be applied, but the thickness of the elastic layer 12 is increased in order to improve uneven transferability. As a coating method for forming a thick film, die coating and spiral coating are excellent, and spiral coating is excellent from the point that the thickness of the elastic layer can be easily changed in the width direction. Yes. Therefore, here, spiral coating will be described. First, while rotating the base layer 11 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, and the paint is spirally applied onto the base layer 11. Work. The paint applied spirally on the base layer 11 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.

<Method for preparing surface state of intermediate transfer belt using coating material>
A case where the surface layer 13 is formed using a coating material as a surface treatment method on the surface of the elastic layer 12 will be described. The vulcanized elastic layer 12 is then sufficiently cooled, and then a coating material is applied onto the elastic layer 12 to obtain a desired seamless belt (intermediate transfer belt). As a coating method, as in the case where the base layer 11 and the elastic layer 12 are formed, an existing coating method such as spiral coating, die coating, roll coating, or spray coating can be applied. The coating material applied on the base layer 11 (and the elastic layer 12) is dried while being leveled by maintaining a predetermined rotation speed and drying temperature. In this drying process, it is preferable to circulate and remove atmospheric vapor (such as a volatile solvent) efficiently as in the method of manufacturing the base layer 11.
After sufficiently cooling, the whole base layer is detached from the mold to obtain a seamless belt (intermediate transfer belt).

<Method for producing surface state of intermediate transfer belt using spherical fine particles 14>
A case where spherical fine particles 14 are applied as a surface treatment method on the surface of the elastic layer 12 will be described. The vulcanized elastic layer is then sufficiently cooled, and subsequently spherical fine particles are applied onto the elastic layer 12 to form spherical fine particles to obtain a desired seamless belt (intermediate transfer belt). As shown in FIG. 9, a spherical particle layer is formed by installing a powder supply device 95 and a pressing member 93, and uniformly coating the surface with spherical particles 94 from the powder supply device 95 while rotating. The spherical particles 94 that are covered are pressed against the pressing member 93 at a constant pressure. The pressing member 93 removes excess particles while embedding particles in a resin layer (belt coated with the base layer 11 and the elastic layer 12) 92 on the mold drum 91. 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 burial rate is adjusted by adjusting the pressing time of the pressing member here.

  The adjustment of the burying rate of the spherical fine particles 14 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 93. . For example, although it depends on the viscosity of the casting coating liquid, the solid content, the amount of the solvent used, the particle material, etc., as a guideline, the pressing force is 1 mN / cm at a viscosity of 100 to 100,000 mPa · s By setting the range to ˜1000 mN / cm, the burying rate of 50% to 100% can be achieved relatively easily.

  The spherical fine particles 14 are uniformly arranged on the surface, and then heated at a predetermined temperature and a predetermined time while rotating, thereby forming an elastic layer in which the particles are hardened and embedded with the particles. After sufficiently cooling, the whole base layer is detached from the mold to obtain a seamless belt (intermediate transfer belt).

<Method for Measuring Buried Rate of Spherical Fine Particles 14 on Intermediate Transfer Belt>
The method for measuring the burying rate of the spherical fine particles 14 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 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, the occupied area ratio, and the thickness of the coating material. The resistance can be measured by using a commercially available measuring instrument, for example, by using Hiresta manufactured by Dia Instruments.

<Adjustment of belt width and surface treatment on belt side>
After obtaining a seamless belt (intermediate transfer belt), both ends of the belt are cut in order to align the width of the belt. An endless belt base was stretched around a plurality of support rollers, and the belt base was rotated and moved by these rollers. As a result of the cutting, the elastic layer 12 is exposed on the side surface of the intermediate transfer belt, but a coating material for forming the spherical fine particles 14 or the resin layer 15 is applied, and at least the elastic layer 12 on the side surface of the intermediate transfer belt is subjected to a surface treatment. Do. Note that the surface treatment agent may adhere to the surface of the intermediate transfer belt if it does not fall within the effective image area width of the surface of the intermediate transfer belt. In this way, a desired seamless belt (intermediate transfer belt) having a surface treatment on the side surface of the belt is obtained.

(Image forming device)
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.

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 image carriers having developing units corresponding to the 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. 10 is a schematic diagram of a main part for explaining an image forming apparatus equipped with the intermediate transfer belt according to the present invention.
An intermediate transfer unit 500 shown in FIG. 10 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. 10 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. 10, 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 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. 11 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. 11, the printer body 10 includes an image writing unit 12, an image forming unit 13, and a paper feeding unit 14 for performing color image formation by an electrophotographic method. Based on the image signal, the image processing unit converts the image into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation and transmits them to the image writing unit 12. To do. The image writing unit 12 is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group. Image writing corresponding to each color signal is performed on image carriers (photoconductors) 21BK, 21M, 21Y, and 21C that have a writing optical path and are provided for each color of the image forming unit 13.

  The image forming unit 13 includes photoconductors 21BK, 21M, 21Y, and 21C that are image carriers for black (BK), magenta (M), yellow (Y), and cyan (C). As each photoconductor for each color, an OPC photoconductor (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.
The film thickness (C) at the center of the belt was calculated by obtaining an 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.

[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 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.

<Preparation 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 A having a film thickness of 60 μm was obtained.

<Production of elastic layer to polyimide base layer belt>
Each constituent material shown below was blended and kneaded to prepare a rubber composition.

<Elastic layer material>
・ 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. Nova Excel 140F) 10 parts by weight 40 parts by weight of aluminum oxide (Hijilite H42M manufactured by Showa Denko KK) and cross-linking agent (Diak No. 1 manufactured by DuPont Dow Elastomer Japan)
(Hexamethylenediamine carbamate)) 0.6 part by weight / crosslinking accelerator (VULCOFAC ACT55, manufactured by Safari alcan)
(70% 1,8-diazabicyclo (5,4,0) undecene-7 salt with dibasic acid, 30% amorphous silica)
0.6 parts by weight, conductive agent (QAP-01 manufactured by Nippon Carlit Co., Ltd.)
(Tetrabutylammonium perchlorate) 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.

<Production of surface layer>
Then, it was taken out from the dryer and cooled, and a fluororesin (Lumiflon: Asahi Glass) dissolved in an organic solvent (MEK: methyl ethyl ketone) was coated on the surface of the belt in a spiral manner while rotating the cylindrical support to form a surface layer. . The coating amount was such that the final film thickness at the center was 555 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. After sufficient organic solvent was removed, the left and right sides of the belt were cut to adjust the width of the belt.

<Processing on the side of the intermediate transfer belt>
Using a sponge, spherical fine particles (Tospearl 120 (volume average particle size 2.0 μm); Momentive Performance Materials) were coated on the side surface where the elastic layer component was exposed by cutting the belt. An intermediate transfer belt A was obtained by pressing the pressing member of the polyurethane rubber blade and fixing it to the side surface.

[Example 2]
An intermediate transfer belt B having irregularities formed by spherical fine particles on the surface and side surfaces of the intermediate belt as shown in FIG. 5 is obtained in the same manner as in Example 1 except that <preparation of surface layer> in Example 1 is changed as follows. It was.

<Production of surface layer>
Take out from the dryer, cool down, and use the device shown in FIG. 9 on the surface to uniformly distribute silicone spherical fine particles (Tospearl 120 (volume average particle size 2.0 μm); Momentive Performance Materials) as spherical fine particles. It was dusted on the surface. The pressing member of the polyurethane rubber blade was fixed to the elastic layer by pressing with a pressing force of 100 mN / cm. 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. Thereafter, the left and right sides of the belt were cut to adjust the width of the belt.

[Example 3]
In <Processing of the side surface of the intermediate transfer belt> in Example 2, an acrylic resin (ACRYDIC A-405; DIC Corporation) dissolved in n-butal as a surface treatment agent was applied by a spray coating method, and the temperature rising rate was 4 ° C. The intermediate transfer belt surface as shown in FIG. 6 has a concavo-convex shape due to spherical fine particles, except that the temperature is increased to 100 ° C./minute and heated for 30 minutes for coating. An intermediate transfer belt C coated with acrylic resin on the belt side surface was obtained.

[Example 4]
In <Processing of intermediate transfer belt side surface> in Example 2, except that the coating material was applied and UV cured using an acrylate UV curable resin (Unidic RC29-117: DIC Corporation) as a surface treating agent. The same procedure as in Example 2 was performed to obtain an intermediate transfer belt D in which the surface of the intermediate transfer belt had a concavo-convex shape of spherical fine particles and the side surface of the intermediate transfer belt was coated with a UV curable resin.

[Example 5]
In the last step of <Processing of intermediate transfer belt side surface> in Example 2, the same procedure as in Example 2 was performed except that a reinforcing tape (double-sided Kapton insulating tape) was attached to the side surface as a protective layer. The reinforcing tape was bonded so as to cover about 1.0 cm of the front and back surfaces of both ends. Note that 1.0 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. As shown in FIG. 7, an intermediate transfer belt E having a belt side surface protected by a reinforcing tape was obtained.

[Comparative Example 1]
An intermediate transfer belt F was obtained in the same manner as in Example 1 except that the intermediate transfer belt side surface was not processed in the processing of the intermediate transfer belt side surface of Example 1.

[Comparative Example 2]
In the processing of the side surface of the intermediate transfer belt in Example 2, the intermediate transfer belt G was obtained in the same manner as in Example 2 except that the side surface of the intermediate transfer belt was not processed.

<Comparative Example 3>
In <Processing of the side surface of the intermediate transfer belt> in Example 2, a reinforcing tape (double-sided Kapton insulating tape) was bonded as a protective layer so as to cover only about 1.0 cm on the front and back surfaces of both ends of the belt. An intermediate transfer belt H as shown in FIG. 8 was obtained in the same manner as in Example 2 except for the processing. Note that 1.0 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 intermediate transfer belts A to H of the above examples and comparative examples were mounted on the image forming apparatus shown in FIG. 11 and evaluated as follows.
The state of wear of the belt after continuous 200,000 sheets of plain paper (TYPE 6200) was confirmed by visual rank determination. Judgment is that ◎ indicates no wear, ○ indicates that there is wear but is a practical level, and × indicates that wear is intense.
In order to investigate white spots due to worn elastic material, the image quality (full-tone halftone with black toner) on plain paper (TYPE 6200) after continuous 200,000 sheets of plain paper (TYPE 6200) was passed. Judgment was made visually. In the judgment, ◎ indicates no white space, ○ indicates white space, but it is usable level, and × is unusable.
In order to investigate the influence of poor running due to belt wear, image distortion was confirmed. The image quality (full-tone halftone with black toner) on plain paper (TYPE 6200) after continuous 200,000 continuous passes of plain paper (TYPE 6200) was visually determined. In the judgment, ◎ indicates no distortion, ○ indicates that there is some distortion, but the actual usable level, and x indicates that it cannot be used.

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

  From the above results, according to the present invention, a highly durable electrophotographic image forming apparatus that can realize high transfer performance regardless of the type and surface shape of the transfer medium and that does not scrape from the side of the belt. An intermediate transfer belt to be mounted can be provided.

(Reference numerals in FIGS. 1 to 8)
DESCRIPTION OF SYMBOLS 11 Base layer 12 Elastic layer 13 Surface layer 14 Spherical fine particle 15 Side surface protective layer (resin)
16 Reinforcement tape (reference numeral in FIG. 9)
91 Mold drum 92 Belt 93 coated with base layer and elastic layer Pressing member 94 Spherical fine particle 95 Powder coating device (reference numeral in FIG. 10)
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. 11) )
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-A-8-85645 Japanese Patent No. 4228667 Japanese Utility Model Publication No. 2-95070 JP 2010-217909 A Japanese Patent No. 4430892

Claims (9)

A toner image in which a latent image formed on an image carrier is developed with toner is primarily transferred, and transfer residual toner remaining after the toner image is secondarily transferred to a recording medium is toner. An intermediate transfer belt cleaned by a cleaning member having a seal member for preventing scattering,
A base layer, and an elastic layer laminated on the base layer,
The intermediate transfer belt is characterized in that a side surface of the elastic layer is subjected to a surface treatment. The elastic layer has spherical fine particles on the surface,
The intermediate transfer belt according to claim 1, wherein the spherical fine particles are formed by forming an uneven shape on a surface of the elastic layer. The elastic layer has spherical fine particles on its side surface,
3. The intermediate transfer belt according to claim 1, wherein the spherical fine particles are formed to have a concavo-convex shape on a side surface of the elastic layer.   The intermediate transfer belt according to claim 1, wherein the elastic layer has a resin protective layer containing a resin on a side surface.   The intermediate transfer belt according to claim 4, wherein the resin protective layer includes a UV curable resin.   The intermediate transfer belt according to claim 1, wherein the elastic layer has a reinforcing tape on a side surface. A manufacturing method for manufacturing the intermediate transfer belt according to any one of claims 1 to 6,
(1): forming the base layer;
(2): forming the elastic layer on the base layer;
(3): cutting both ends so that the base layer and the elastic layer obtained in (2) have a predetermined width;
(4): a step of performing a surface treatment on the side surface of the elastic layer after cutting according to (3),
A process for producing an intermediate transfer belt, comprising: 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 8, wherein the image carrier is disposed along the intermediate transfer belt.