JP5696840B2 - Intermediate transfer belt, image forming apparatus, and method of manufacturing intermediate transfer belt - Google Patents

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, seamless belts have been used as members for various uses in electrophotographic apparatuses. Particularly in recent full-color electrophotographic apparatuses, an intermediate transfer belt system in which developed images of four colors of yellow, magenta, cyan, and black are once overlaid on an intermediate transfer medium, and then collectively transferred to a transfer medium such as paper. 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 fluctuations due to deformation such as elongation of the belt itself due to continuous use. Further, the intermediate transfer belt is laid out over a wide area of the apparatus, and is required to be flame retardant because a high voltage is applied for transfer. In order to meet such requirements, polyimide resins, polyamideimide resins, and the like that are high elastic modulus and high heat resistance resins are mainly used as intermediate transfer belt materials.

  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 ordinary 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 layer is laminated on a base layer have been proposed.

  However, when the surface layer is a relatively flexible layer, the transfer pressure is reduced and the followability to paper irregularities is improved, but the toner cannot be released well due to the poor surface releasability. There is a problem that transfer efficiency is lowered and the former effect cannot be utilized. There is also a problem that it is inferior in wear resistance and scratch resistance.

In order to solve this problem, there is a method of newly providing a protective layer, but when coated with a material with sufficiently high transfer performance, there is a problem that the flexibility of the flexible layer cannot be followed and cracking or peeling occurs. Since it occurs, it is not preferable.
Therefore, as a method for protecting a flexible surface layer without causing the above-described problems, proposals have been made to improve transferability by attaching fine particles to the surface.

  Patent Document 1 proposes coating with beads having a diameter of 3 μm or less. However, the technique according to Patent Document 1 is not sufficient in terms of durability required for recent electrophotographic apparatuses because particles (beads) are detached.

  In Patent Documents 2 and 3, it is proposed to form a layer with a material having affinity for the hydrophobized fine particles. In these, particles having a very small particle size are preferably used. However, the particle layer is thick, there are non-uniform portions due to the aggregation of particles, and the transfer performance also varies, and there are those that can satisfy the high level of image quality required for recent electrophotographic devices. I can't get it.

  Patent Documents 4 and 5 propose a configuration that realizes durability by using relatively large particles and embedding in resin to some extent. However, even with such a proposal, non-uniformity occurs in the presence of particles, and it is impossible to obtain a product that can satisfy the high level of image quality required for recent electrophotographic apparatuses.

In all of Patent Documents 1 to 5, silica is preferably used. However, since silica particles have a strong cohesive force, a uniform particle layer cannot be formed as described above.
In addition, inorganic particles such as silica tend to scratch and wear the surface of the organic photoreceptor due to contact with the organic photoreceptor that is preferably used as a latent image carrier for image formation, and reduce durability. This causes the problem of

The present invention has been made in view of the above prior art, is flexible and excellent in toner releasability, can achieve a high transfer rate regardless of the transfer medium, and is sustainable for a long time. It is an object of the present invention to obtain an intermediate transfer belt for realizing a high-quality electrophotographic apparatus and a method for producing the intermediate transfer belt.
Another object of the present invention is to obtain a long-lasting and high-quality electrophotographic apparatus provided with the intermediate transfer belt.
Hereinafter, the “electrophotographic apparatus” may be referred to as an “image forming apparatus”.

As a result of intensive studies, the present inventors have found an intermediate transfer belt to which a toner image obtained by developing a latent image formed on a carrier with toner is transferred. The intermediate layer is laminated on the base layer. An elastic layer, the elastic layer containing an elastic body and spherical resin particles, and having a concavo-convex shape formed on a surface thereof, wherein the spherical resin particles are arranged in a plane direction on the surface of the elastic layer. It has been found that the above-mentioned problems can be solved by an intermediate transfer belt which is arranged and has a glossiness of 35% or less measured at 85 ° reflected light on the surface of the intermediate transfer belt.
That is, the said subject is solved by invention described in the following [1]-[8].

[1]: An intermediate transfer belt to which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred, and includes a base layer and an elastic layer laminated on the base layer The elastic layer contains an elastic body and spherical resin particles, and has an irregular shape formed on the surface, and the spherical resin particles are arranged in a plane direction on the surface of the elastic layer, the elastic layer is, the projected area ratio of the exposed portion of the spherical resin particles at the surface is 60% or more, the gloss degree of 85 ° reflected light measurement of the surface of the intermediate transfer belt is not more than 35%, the spherical resin The particles include two or more types of particle groups having different volume average particle sizes, and the two or more types of particle groups include a group A having the largest volume average particle size and a group B having the second largest volume average particle size. The volume average particle diameter a of the group A , A volume-average particle diameter b of the group B, an intermediate transfer belt to satisfy the relation of a / 5 ≦ b ≦ 4a / 5.
[2] The intermediate transfer belt according to [1] , wherein the number of the group A existing in the elastic layer is 20% by number or more with respect to the total number of the spherical resin particles. .
[3] The intermediate transfer belt according to [1] or [2] , wherein the volume average particle diameter a of the group A is 1.0 μm to 5.0 μm.
[4] The intermediate transfer belt according to any one of [1] to [3] , wherein the spherical resin particles are silicone resin particles.
[5] : An image forming apparatus comprising the intermediate transfer belt according to any one of [1] to [4] .
[6] : A method for producing the intermediate transfer belt according to any one of [1] to [4] , wherein the step of forming the base layer, the step of forming the elastic body, A step of uniformly drying and applying the spherical resin particles on the elastic body; and a step of uniformly forming the spherical resin particles by arranging and embedding the spherical resin particles. This is a method for manufacturing an intermediate transfer belt.

According to the present invention, a flexible, excellent toner releasability, a high transfer rate can be realized regardless of a transfer medium, and a long-lasting, high-durability and high-quality electrophotographic apparatus can be realized. The intermediate transfer belt and a method for producing the intermediate transfer belt can be provided.
Further, according to the present invention, there is provided a highly durable and high-quality electrophotographic apparatus capable of realizing high transfer performance not only in the initial stage but also in the long term, regardless of the type and surface properties of the transfer medium. be able to.

FIG. 3 is a schematic diagram illustrating a layer configuration example of an intermediate transfer belt in the present invention. The schematic diagram of the cross-sectional form of the surface layer of the intermediate transfer belt in this invention is shown. FIG. 3 is a schematic diagram of a cross-sectional form of the surface of an intermediate transfer belt in which the heights of the portions where spherical resin particles are exposed from the elastic layer are aligned. 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 onto which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred. The intermediate transfer belt is formed on the base layer 11 and the base layer 11. An elastic layer 12 that is laminated. The elastic layer 12 includes an elastic body and spherical resin particles 13, and has a concavo-convex shape formed on a surface thereof, and the spherical resin particles 13 include the elastic layer 12. The elastic layer 12 has a projected area ratio of 60% or more of the exposed portion of the spherical resin particles 13 on the surface, and the 85 ° reflected light on the surface of the intermediate transfer belt. The glossiness measured is 35% or less.
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 apparatus, a seamless belt is used for several members, and an intermediate transfer member (intermediate transfer belt) is one of important members that require electrical characteristics. The intermediate transfer belt of the present invention will be described below.

The intermediate transfer belt of the present invention is an intermediate transfer belt type electrophotographic apparatus [so-called a plurality of color toner developed images sequentially formed on an image carrier (for example, a photosensitive drum) are sequentially superimposed on the intermediate transfer belt. The seamless belt is suitable for use in a device that performs primary transfer and transfers the primary transfer image collectively to a recording medium (hereinafter also referred to as a transfer medium).
FIG. 1 shows a layer structure of an intermediate transfer belt preferably used in the present invention. However, it is not limited to this configuration.
As a configuration, a flexible elastic layer 12 is laminated on a rigid base layer 11 that can be relatively flexible, and a layer 13 of spherical resin particles is formed on the outermost surface of the elastic layer 12. .

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

Examples of the electrical resistance adjusting material include a metal oxide, carbon black, an ionic conductive agent, and a conductive polymer material.
Examples of the metal oxide include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. Moreover, in order to improve dispersibility, the metal oxide may be subjected to surface treatment in advance.
Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black.
Examples of the ionic conductive agent include 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.
The electrical resistance adjusting material in the present invention is not limited to the above exemplary compounds.

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

The electrical resistance adjusting material 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. Although the amount is 10 ¹² Ω · cm, it is necessary to select and add an amount in a range where the molded film is brittle and does not easily break from the viewpoint of mechanical strength.
In other words, in the case of an intermediate transfer belt, an electrical characteristic (for example, a coating liquid in which the blending of the resin component (for example, a polyimide resin precursor or a polyamideimide resin precursor) and an electrical resistance adjusting material is appropriately adjusted is used. It is preferable to manufacture and use a seamless belt having a balance between surface resistance and volume resistance) and mechanical strength.

  In the case of carbon black, the content of the electric resistance adjusting material in the present invention is 10 to 25 wt%, preferably 15 to 20 wt% of the total solid content in the coating liquid. Moreover, as content in the case of a metal oxide, it is 1-50 wt% of the total solid of a coating liquid, Preferably it is 10-30 wt%. If the content is less than the range of the respective electric resistance adjusting materials, 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.

(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. However, a material having sufficient flexibility (elasticity) to sufficiently exhibit the effects of the present invention should be 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 thermosetting include polyurethane, silicone-modified epoxy, and silicone-modified acrylic.
Examples of the rubber material include isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, chloroprene rubber, acrylic rubber, chlorosulfonated polyethylene, fluorine rubber, urethane rubber, and hydrin rubber. .
A material capable of obtaining 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 a spherical resin particle layer on the surface of this material, a thermosetting material is preferable to a thermoplastic material. The thermosetting material is excellent in adhesiveness with the 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 addition to the above selected materials, electrical resistance modifiers for adjusting electrical characteristics, flame retardants for obtaining flame retardancy, antioxidants, reinforcing agents, fillers, vulcanization accelerators, etc., if necessary The above ingredients are mixed appropriately.

As the electrical resistance adjusting agent for adjusting the electrical characteristics, the various materials described above can be applied. However, since carbon black, metal oxide, and the like impair flexibility, it is preferable to reduce the amount used. It is also effective to use a conductive polymer. Moreover, you may use these together.
The resistance value of the elastic body 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.
The thickness of the elastic body is preferably about 200 μm to 2 mm. 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 more likely to bend, resulting in instability in running performance, and because cracks are likely to occur due to bending at the roller curvature portion for stretching the belt, such being undesirable.

Next, the spherical resin particles 13 formed on the surface of the elastic body will be described.
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. Silicone resin particles tend to have the highest transfer rate.
In addition, the particle A having the largest particle diameter has the highest chance of contacting with the toner. Therefore, what is the material of the particles A tends to affect the transfer rate in particular.
It is preferable that the resin is a particle formed into a spherical shape by a polymerization method or the like using these resins.

Next, FIG. 2 shows an enlarged schematic sectional view of the belt surface.
In the present invention, the spherical resin particles 13 are preferably embedded in the elastic layer 12, and the burying rate is preferably more than 50% and less than 100%. If it is 50% or less, particle detachment tends to occur during long-term use in an electrophotographic apparatus, resulting in poor durability. On the other hand, 100% is not preferable because the effect of the particles on the transferability is reduced.
In the present invention, it is preferable that the height of the portion where each spherical resin particle 13 is exposed from the surface of the elastic body varies to some extent. This is because the exposed height of the spherical resin particles 13 varies to some extent as compared with the intermediate transfer belt (FIG. 3) in which the height of the portion where the particles are exposed from the elastic body in the elastic layer 12 is uniform. This is because the number of contact points between the spherical resin particles 13 having excellent releasability and the toner 14 is increased, and transfer efficiency can be further improved as compared with the case where the exposed height of the spherical resin particles 13 is uniform.
Thus, when the height of the outermost surface of the particles is varied to some extent, the glossiness in the 85 ° reflected light measurement on the surface of the intermediate transfer belt is 35% or less.

As described above, in the present invention, it is preferable to vary the height of the portion where the spherical resin particles 13 are exposed from the elastic body to some extent. However, as a specific means for that purpose, at least two kinds of average particle diameters are different. It is preferable to use a combination of spherical resin particle groups.
When only one type of spherical resin particle is used to obtain the target surface state of the present invention, it is necessary to change the burying rate of each particle, which is not suitable for mass production. On the other hand, when spherical resin particle groups having different average particle diameters of at least two types are used in combination, it is possible to obtain the target surface state of the present invention relatively easily by aligning the burial rate of each particle. It is.

The volume average particle size of the group A having the largest volume average particle size among the particle groups is preferably 1.0 μm to 5.0 μm. When the particle size is less than 1.0 μm, the effect of transfer performance due to the particles cannot be sufficiently obtained. On the other hand, when the particle size is more than 5.0 μm, the particles are often insulating. Due to the remaining of the charging potential due to the above, there occurs a problem that image disturbance occurs due to accumulation of the potential during continuous image output.
Further, the volume average particle diameter a of the A group having the largest volume average particle diameter among the particle groups and the volume average particle diameter b of the B group having the second largest volume average particle diameter are a / 5 ≦ b ≦ 4a. It is preferable to satisfy the relationship of / 5. If b is too small, the height variation of the portion where the spherical resin particles 13 are exposed from the elastic body becomes too large, the toner 14 does not come into contact with the B group, and sufficient transfer performance is not exhibited. Residual toner cleaning performance in a system using a blade is deteriorated, and foreign matter is easily filmed in the recess. On the other hand, if b is too large, the variation in the height of the portion where the spherical resin particles 13 are exposed from the elastic body cannot be obtained sufficiently.
For the same reason as described above, it is desirable that the number of particles in group A having the largest volume average particle diameter in the particle group accounts for at least 20% or more of the total number of particle groups.

Such spherical resin particles 13 can be easily and uniformly aligned by directly applying powder directly onto the elastic body.
When the spherical resin particles 13 are applied on the elastic body, it is preferable to supply a sufficient amount of spherical resin particles. If the supply amount of the spherical resin particles is small, a region where the elastic body is exposed without being covered with particles becomes large, and not only the toner transfer property but also the residual toner cleaning property and the filming resistance are remarkably deteriorated.
Specifically, a sufficient amount of spherical resin particles is supplied so that the projected area ratio of the exposed portion of the particle layer is 60% or more with respect to the projected area ratio between the exposed portion of the elastic body and the exposed portion of the particle. preferable. The higher the particle area ratio, the higher the transfer ratio. The higher the particle area ratio is considered to be because the area where the elastic body not covered with the particles is exposed decreases. (While particles are excellent in toner transferability, elastic bodies are inferior in toner transferability.)
In addition, the combination of three kinds of particles tends to fill the gap more easily than the combination of two kinds of particles, so that the particle area ratio tends to be increased.

  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 with respect to the elastic layer 12. As shown in FIG. 4, in the configuration including a plurality of particles in the thickness direction, the distribution of the particles becomes uneven, and the electrical characteristics of the belt surface become non-uniform due to the influence of the electric resistance value of the particles. Disturbs. Specifically, the electrical resistance value in the portion where many particles are present becomes high, a surface potential is generated due to the residual charge, and the surface potential varies on the belt surface, resulting in the image density in the adjacent portion. Image disturbance due to a difference or the like becomes obvious.

(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 sufficiently defoamed in advance is poured into the paint pan in 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 in which the paint is poured into the lower part of the application roller is approached and immersed in the paint, and the paint is adhered to the surface of the application roller at a slow peripheral speed of 10 to 100 mm / sec and pumped upward. Thereafter, the thickness of the paint on the application roller is adjusted by a regulating roller which is installed on the upper part of the application roller and can adjust an arbitrary gap with the application roller. The thickness of the paint to be regulated is preferably about twice the thickness of the paint transferred to the cylindrical support.
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 or less. The paint on the application roller is transferred onto the cylindrical support E rotating in the same direction as the application roller C (the “clockwise direction” in the direction shown in FIG. 5), and the cylindrical support is transferred. A paint having a predetermined film thickness is deposited on E.
After coating, 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. 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. 6, 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 the belt 32 formed by applying the base layer 11 and the elastic body supported by the mold drum 31. In the present invention, at least two kinds of particles having different volume average particle diameters are used, and those mixed in advance at a desired ratio are supplied to the powder supply apparatus.
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). it can. 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-described 50% <buried ratio <100% and h _max −h _min ≦ 0.2 μm can be achieved relatively easily.
After the uniform particle layer is formed, the elastic layer 12 is formed by curing by heating at a predetermined temperature for a predetermined time.

  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. 7 is a schematic view 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. 7 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 drive roller 508 that is driven to rotate in the arrow direction by a drive motor (not shown).
The intermediate transfer belt 501 as a belt member is usually a semiconductor or an insulator and has a single-layer or multi-layer structure. However, in the present invention, a seamless belt is preferably used, thereby improving durability. Excellent image formation can be realized. Further, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose the toner images formed on the photosensitive drum 200.

  A secondary transfer bias roller 605 serving as a secondary transfer unit is attached to and separated from a belt outer peripheral surface of the intermediate transfer belt 501 in a portion stretched around the secondary transfer counter roller 510 by a contact / separation mechanism, which will be described later. It is configured to be able to contact and separate. The secondary transfer bias roller 605 is disposed so as to sandwich the transfer paper P, which is a 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. 7, a charging charger 203 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with a negative charge by corona discharge. The timing is determined based on the belt mark detection signal, and raster exposure with laser light is performed based on the Bk color image signal by a writing optical unit (not shown). When this raster image is exposed, the charge proportional to the exposure light amount disappears in the exposed portion of the surface of the photosensitive drum 200 that is initially uniformly charged, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing device 231K comes into contact with this Bk electrostatic latent image, the toner does not adhere to the remaining portion of the photosensitive drum 200, and the charge is not charged. The toner is attracted to the nonexposed portion, that is, the exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

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

Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the C electrostatic latent image arrives, the revolver developing unit 230 is rotated, and the C developing machine 231C develops. The C electrostatic latent image is developed with C toner. Thereafter, the development of the C electrostatic latent image area is continued. When the rear end of the C electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the case of the previous Bk developing machine 231K. The M developing machine 231M is moved to the developing position. This is also completed before the leading edge of the next Y electrostatic latent image reaches the developing position. Note that the M and Y image forming steps are the same as the Bk and C steps described above because the operations of reading color image data, forming an electrostatic latent image, and developing are the same as those described above.
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) in which four colors at the maximum are superimposed on the intermediate transfer belt 501 is formed. On the other hand, at the time when the image forming operation is started, the transfer paper P is fed from a paper feed unit such as a transfer paper cassette or a manual feed tray, and is waiting at the nip of the registration roller 610.
When the leading edge of the toner image on the intermediate transfer belt 501 reaches the secondary transfer portion where the nip is formed by the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and the secondary transfer bias roller 605. Then, the registration roller 610 is driven so that the leading edge of the transfer paper P coincides with the leading edge of the toner image, and the transfer paper P is conveyed along the transfer paper guide plate 601, and the transfer paper P and the toner image are transferred. Resist alignment is performed.

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

  On the other hand, the surface of the photosensitive drum 200 after the belt transfer is cleaned by the photosensitive member cleaning device 201 and is uniformly discharged by the discharging lamp 202. 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 is provided that contacts and separates from the outer peripheral surface of the intermediate transfer belt 501. 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, for example, a plurality of photosensitive drums as illustrated 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. 8 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. 8, 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.

  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. 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.

<Production of elastic layer on base layer>
The respective constituent materials shown below were 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 Beads 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, silicone resin particles (Tospearl 130 (volume average particle size of 3.0 μm)) are used as spherical resin particles by using the method of FIG. 6; Momentive Performance Materials) 50 wt% and silicone resin particles (Tospearl 120 (volume average particle diameter 2.0 μm product); Momentive Performance Materials) 50 wt% of the mixed particles are thoroughly applied to the surface, and the polyurethane rubber blade The pressing member was pressed and fixed to the elastic layer.
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. After sufficiently cooling, it was removed from the mold to obtain an intermediate transfer belt A.

[Example 2]
The spherical resin particles in Example 1 were mixed with silicone resin particles (Tospearl 145 (volume average particle size 4.5 μm product); Momentive Performance Materials) 60 wt% and silicone resin particles (Tospearl 120 (volume average particle size 2. 0 μm product); Momentive Performance Materials) An intermediate transfer belt B was obtained except that 40 wt% of the mixed particles were sufficiently mixed.

[Example 3]
The spherical resin particles in Example 1 were mixed with 40 wt% of silicone resin particles (KMP-590 (volume average particle size 2.0 μm product); Shin-Etsu Silicone) and silicone resin particles (X-52-854 (volume average particle size of 0.1 μm). 8 μm product); Shin-Etsu Silicone) An intermediate transfer belt C was obtained in the same manner except that 40 wt% of the mixed particles were sufficiently mixed.

[Example 4]
The spherical resin particles in Example 1 were mixed with 40 wt% of silicone resin particles (X-52-1621 (volume average particle size: 5.0 μm product); Shin-Etsu Silicone) and silicone resin particles (KMP-701 (volume average particle size: 3. 5 μm product); Shin-Etsu Silicone) 40 wt% and silicone resin particles (X-52-854 (volume-average particle size 0.8 μm product); Shin-Etsu Silicone) 20 wt% were replaced with mixed particles and the same. An intermediate transfer belt D was obtained.

[Example 5]
The spherical resin particles in Example 1 were mixed with 50 wt% acrylic resin particles (NMB-0520 (volume average particle size: 5.0 μm product); Shin Nippon Oil Co., Ltd.) and acrylic resin particles (NMB-0320 (volume average particle size 3). Intermediate transfer belt E was obtained except that the mixed particles were sufficiently mixed with 50 wt%.

[Example 6]
The spherical resin particles in Example 1 were mixed with melamine-silica resin particles (Opto beads 6500M (volume average particle size 6.5 μm product); Nissan Chemical Industries, Ltd.) 40 wt% and melamine-silica resin particles (Opto beads 3500M (volume). Average particle size 3.5 μm product); Nissan Chemical Industries, Ltd.) 30 wt% and melamine-silica resin particles (Opto beads 2000M (volume average particle size 2.0 μm product); Nissan Chemical Industries, Ltd.) 30 wt% An intermediate transfer belt F was obtained in the same manner except that the mixed particles were mixed.

[Example 7]
The spherical resin particles in Example 1 were mixed with silicone resin particles (Tospearl 145 (volume average particle diameter 4.5 μm product); Momentive Performance Materials) 50 wt% and acrylic resin particles (NMB-0320 (volume average particle diameter 3). 0.5 μm product); Shin Nippon Oil Co., Ltd.) An intermediate transfer belt G was obtained in the same manner except that the mixed particles were sufficiently mixed with 50 wt%.

[Example 8]
The spherical resin particles in Example 1 were mixed with melamine-silica resin particles (Opto beads 3500M (volume average particle diameter 3.5 μm product); Nissan Chemical Industries, Ltd.) 50 wt% and silicone resin particles (KMP-590 (volume average particles). An intermediate transfer belt H was obtained in the same manner except that the mixed particles were sufficiently mixed with 50 wt%.

[Comparative Example 1]
An intermediate transfer belt I was prepared in the same manner as in Example 1 except that the particle layer was not formed.

[Comparative Example 2]
An intermediate transfer belt J was prepared in the same manner as in Example 1 except that the spherical resin particles were not sufficiently supplied in the particle coating step.

[Comparative Example 3]
An intermediate transfer belt K was prepared in the same manner as in Example 1 except that only melamine-silica resin particles (Opto beads 500S (volume average particle size 0.5 μm); Nissan Chemical Industries, Ltd.) were used as spherical resin particles. did.

The following evaluations were performed on the intermediate transfer belts A to K of each of the above examples and comparative examples.
<Measurement of glossiness>
Using a handy gloss meter (PG-1M; Nippon Denshoku Industries Co., Ltd.), the surface glossiness of each belt with 10 points of 85 ° reflected light was measured, and the average was used as measurement data.
<Measurement of spherical resin particle quantity ratio>
The surface of each belt was observed with a scanning electron microscope, and the quantity ratio of particle groups having different average particle diameters was calculated from the observed images.
<Measurement of belt surface particle area ratio (projected area ratio of exposed portion of spherical resin particles)>
The surface of each belt is observed with a scanning electron microscope, and the image is binarized using image processing software (Image-plus; cyber-netics), and the projected area of the exposed portion of the elastic body and the exposed portion of the particle The rate was calculated.

Further, the intermediate transfer belts A to K of the above examples and comparative examples were mounted on the electrophotographic apparatus of FIG.
<Measurement of transfer rate>
As the transfer paper, a paper having a concavo-convex pattern on the surface (continuous amount 215 kg paper, rezac paper) is used, and an operation for outputting a blue solid image is performed on the paper, on the intermediate transfer belt before being transferred to the paper The amount of image toner and the amount of toner remaining on the intermediate transfer belt after being transferred to paper were measured, and the transfer rate was calculated.

<Measurement of transfer rate at the time of continuous image output of 10,000 sheets>
After continuous output of 10,000 test chart images, the test chart was stopped and the transfer rate was measured according to the above method.
<Evaluation of images when 10,000 continuous images are output>
After continuous output of 10,000 test chart images, a full-tone cyan halftone image was output on a continuous weight of 215 kg paper, and the abnormal image was observed.

The results were as shown in Table 1 below.

Examples 1 to 8 exhibited excellent performance both at the initial stage and after output of 10,000 images.
Since the configuration of Example 4 is a combination of three types of particles, the particle area ratio is high. Further, all the particles used are silicone resin particles having excellent transferability. Therefore, the most excellent transfer rate was shown in this example.
As in Example 4, Example 1 and Example 2 exhibited high transferability because all the particles used were silicone resin particles. However, since the particle area ratio is inferior to that of Example 4, it is considered that the results are not as good as Example 4.
In Example 3, the particles used are silicone resin particles, but the particle diameter of the particle A having the largest particle shape is 2.0 μm, which is smaller than those of other examples 1 and 2. Therefore, the transfer rate is slightly lower.
Example 5 uses acrylic resin particles, and Example 6 uses melamine-silica resin particles, both of which are inferior in toner transfer compared to silicone resin particles, and therefore transfer rates are lower than in other examples. .
Example 7 is a combination of silicone resin particles and acrylic resin particles, and Example 8 is a combination of silicone resin particles and melamine-silica resin particles. In Example 7, the silicone resin particles have a larger particle size. It is considered that the transfer rate is relatively high because the particles having a larger particle diameter have more opportunities to come into contact with the toner. On the other hand, in Example 8, since the melamine-silica particles have a larger particle size, the transfer rate is considered to be relatively low.

On the other hand, in Comparative Example 1 in which no particles were formed, there was no unevenness due to the particles, and thus a relatively high 85 ° gloss was obtained. Further, since no particles were present, the tackiness of the elastic body on the surface did not disappear, and the transfer performance was greatly inferior from the beginning.
In Comparative Example 2, since the particles were not sufficiently supplied, the particles did not completely cover the elastic body. As a result, problems such as toner sticking to a portion where the elastic body is exposed and poor cleaning occur.
In Comparative Example 3, since particles having a single average particle diameter were used, the surface unevenness was small (see FIG. 3). Therefore, the exposed height of the spherical resin particles varies to some extent, and the transfer rate is inferior compared with Examples 1 to 8 in which the number of contact points between the spherical resin particles having excellent releasability and the toner is large.

  As described above, with the configuration of the present invention, an intermediate transfer belt for realizing a high durability and high image quality electrophotographic apparatus that can achieve a high transfer rate irrespective of a transfer medium and can be sustained for a long time is obtained. Can be realized.

(Reference numerals in FIGS. 1 to 4)
11 Base layer 12 Elastic layer 13 Spherical resin particle 14 Toner (reference numeral in FIG. 5)
A Paint pan B Paint C Coating roll D Regulating roll E Cylindrical support (mold)
(Reference in FIG. 6)
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. 7)
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. 8) )
P Transfer paper 10 Printer body 12 Image writing unit 13 Image forming unit 14 Paper feeding unit 15 Fixing device 16 Registration roller 20BK, 20M, 20Y, 20C Developing device 21BK, 21M, 21Y, 21C Photoconductor 22 Intermediate transfer belt 23BK, 23M , 23Y, 23C Primary transfer bias roller 25 Belt cleaning member 26 Drive roller 27 Lubricant coating device 50 Transfer conveyor belt 60 Secondary transfer bias roller

JP-A-9-230717 JP 2002-162767 A JP 2004-354716 A JP 2007-328165 A JP 2009-75154 A

Claims (6)

An intermediate transfer belt to which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred,
A base layer, and an elastic layer laminated on the base layer,
The elastic layer contains an elastic body and spherical resin particles, and an uneven shape is formed on the surface,
The spherical resin particles are arranged in a plane direction on the surface of the elastic layer,
The elastic layer has a projected area ratio of the exposed portion of the spherical resin particles on the surface of 60% or more,
The glossiness of the surface of the intermediate transfer belt measured at 85 ° reflected light is 35% or less ,
The spherical resin particles include two or more kinds of particle groups having different volume average particle diameters, and the two or more kinds of particle groups are the A group having the largest volume average particle diameter and the second largest volume average particle diameter. Group B, and
The intermediate transfer belt , wherein the volume average particle diameter a of the group A and the volume average particle diameter b of the group B satisfy a relationship of a / 5 ≦ b ≦ 4a / 5 . The number of A groups, the intermediate transfer belt according to claim 1, wherein the at 20 number% or more of the spherical resin particles total quantity present in the elastic layer. The volume average particle diameter a of the group A, an intermediate transfer belt according to claim 1 or 2, characterized in that it is 1.0Myuemu～5.0Myuemu. The spherical resin particles, an intermediate transfer belt according to any one of claims 1 to 3, wherein the silicone resin particles. An image forming apparatus comprising the intermediate transfer belt according to claim 1 . A manufacturing method for manufacturing the intermediate transfer belt according to any one of claims 1 to 4 ,
Forming the base layer;
Forming the elastic body;
Applying the spherical resin particles uniformly on the elastic body by drying;
And a step of uniformly forming the spherical resin particles by arranging and embedding the spherical resin particles.

Images