JP5786181B2 - Intermediate transfer belt and electrophotographic apparatus using the same - Google Patents

Description

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

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

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

  Under such circumstances, the required characteristics (high-speed transfer, positional accuracy) of the intermediate transfer belt are also stricter than before, and it is necessary to satisfy the characteristics corresponding to these requirements. Yes. In particular, for positional accuracy, it is required to suppress 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 a high voltage is applied for the transfer, so that it is required to be heat resistant and flame retardant. 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. Roughly surfaced materials such as Japanese paper and kraft paper are increasingly used. Such followability to papers having different surface properties is important. If the followability is poor, uneven unevenness of color and uneven color tone occur.
In 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. Yes, not preferred. On the other hand, proposals have been made to improve transferability by attaching fine particles to the surface.

That is, JP-A-9-230717 of Patent Document 1 proposes coating with beads having a diameter of 3 μm or less.
However, the technique described in this publication causes particle detachment, which is not sufficient with respect to the durability required for recent electrophotographic apparatuses.
Japanese Patent Application Laid-Open No. 2002-162767 and Japanese Patent Application Laid-Open No. 2004-354716 of Patent Document 2 propose forming a layer of a material having affinity for hydrophobized particles.
In these, particles having a very small particle size are preferably used.
However, the particle layer is thick, or there are non-uniform portions due to particle aggregation, resulting in variations in transfer performance, and a product that can satisfy the high level of image quality required of recent electrophotographic devices can be obtained. Absent.
Japanese Patent Application Laid-Open No. 2007-328165 and Japanese Patent Application Laid-Open No. 2007-75154 of Patent Document 4 propose a configuration in which durability is achieved by using relatively large particles and embedding in a surface resin layer to some extent. However, even in these proposals, nonuniformity occurs in the presence of particles, such as overlapping of layer thickness methods among particles and complete embedding of some particles in the resin layer, which is also a high demand for recent electrophotographic apparatuses. You can't get something that satisfies the image quality level.
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
Therefore, the present inventors have embedded the spherical resin particles in the surface resin layer of the intermediate transfer belt so as to be more than 50% and less than 100%, thereby forming a uniform uneven shape in the surface direction. It has been found that the problem is solved and has already been proposed (see Japanese Patent Application No. 2010-009871 of Patent Document 6).
However, in recent years, with the increase in definition of an image, the toner that forms the image has also become smaller in particle size. When the toner has a small particle size, the content of the fine powder toner is increased, and cleaning failure is likely to occur. The toner having the cleaning failure causes image contamination in the next process or filming on the surface of the intermediate transfer member and There is a problem that the transfer performance deteriorates. Thus, the present invention can be said to be a further improvement of the technique already proposed in Patent Document 6.

The present invention has been made in view of the above prior art, is flexible and has excellent toner releasability, can achieve a high transfer rate regardless of the transfer medium, and can use a small particle size toner. The aim is to realize a long-lasting, highly durable, high-quality electrophotographic apparatus.
Hereinafter, the “electrophotographic apparatus” may be referred to as an “image forming apparatus”.

As a result of intensive studies, the present inventors have found that according to a selected combination of a specific intermediate transfer member and a specific toner, an excellent result is obtained as compared with the combination of the other intermediate transfer member and toner. It was found that the above-mentioned purpose can be realized by deceiving.
That is, the said subject is solved by invention described in the following [1]-[ 5 ].

[1] A toner image obtained by visualizing a latent image formed on a latent image carrier with toner is primarily transferred onto an intermediate transfer member, and the primary transferred image on the intermediate transfer member is secondarily transferred onto a transfer material. Then, in the electrophotographic apparatus having a step of cleaning the transfer residual toner remaining on the intermediate transfer belt, the intermediate transfer member is formed on the base layer containing polyimide resin or polyamideimide resin, and the surface thereof is an independent spherical resin. the particles have a resin layer in which a concavo-convex shape is formed of a single particle layer that by the embedded the particles implantation ratio less than 100% more than 50% in the depth direction in a single state, the Spherical resin particles are monodispersed particles having a distribution width of ± (average particle diameter of spherical resin fine particles × 0.5) or less, and the resin forming the resin layer is made of a thermosetting elastomer or rubber material. Including and the electron Use in photographic equipment toner is a volume average particle size of 3 to 7 [mu] m, electrophotographic equipment, wherein the 2μm or less of the particles is 10% by number or less.
[2] The ratio (Dv / Dn) of the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner particles of the toner is in the range of 1.00 to 1.30. The electrophotographic apparatus according to item [1].
[3] The electrophotographic apparatus according to any one of [1] or [2], wherein the toner is a toner prepared by a polymerization method.
[4] The spherical resin particles on the surface of the intermediate transfer member are silicone resin particles having an average particle diameter of 1.0 μm to 5.0 μm, and any one of [1] to [3] The electrophotographic apparatus described in 1.
[ 5 ] The electrophotographic apparatus according to any one of [1] to [ 4 ], wherein the step of cleaning the intermediate transfer member is performed by a contact member having means for applying an electric field. .

  As will be apparent from the following detailed and specific description, according to the present invention, high transfer performance can be maintained not only for the initial period but also for a long period regardless of the type and surface properties of the transfer medium. For a long period of time, an electrophotographic apparatus with high durability and high image quality can be obtained.

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 form of the surface of the intermediate transfer belt in this invention is shown. The schematic diagram of the cross-sectional form of the surface layer of the intermediate transfer belt in this invention is shown. It is a figure explaining the manufacturing method of the resin layer which forms the uniform uneven | corrugated shape by the single particle layer which arranged the spherical resin particle which became independent in the surface direction in preparation of the belt of the structure of this invention. It is a principal part schematic diagram for demonstrating the image forming apparatus equipped with the seamless belt obtained by the manufacturing method which concerns on this invention as a belt member. FIG. 3 is a schematic diagram of a main part showing an example of a configuration of an image forming apparatus in which a plurality of photosensitive drums are arranged in parallel along one intermediate transfer belt formed of a seamless belt according to the present invention.

As described above, the intermediate transfer member of the present invention is characterized in that the surface is formed of a resin layer in which independent spherical resin particles are arranged in a plane direction to form a uniform uneven shape. is there.
Hereinafter, the intermediate transfer member of the present invention will be described in detail.
Examples of the intermediate transfer member include a belt-like member and a drum-like member, but the belt will be described here, but the present invention is not limited to this form.

The present invention relates to an intermediate transfer belt type electrophotographic apparatus [so-called a plurality of color toner development images sequentially formed on an image carrier (for example, a photosensitive drum) are sequentially superimposed on the intermediate transfer belt for primary transfer. The apparatus is suitably equipped as an intermediate transfer belt in a system that performs secondary transfer of the primary transfer image to a recording medium collectively.
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 constitution, a flexible resin layer (12) is laminated on a rigid base layer (11) capable of obtaining relatively flexibility, and spherical resin particles (13) are formed on the outermost surface of the resin layer (12). Are formed in a single state. When the resin particles (13) in the present invention are in a single state, there is almost no overlap in the layer thickness method between the resin particles (13) and no complete embedding of the resin particles (13) in the resin layer (12).

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

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

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 preferable 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 each of the electrical resistance adjusting materials, the effect may not be sufficiently obtained, and if the content is greater than the respective range, the mechanical strength of the intermediate transfer belt (seamless belt) May decrease, which is not preferable for practical use.

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

<Resin layer>
Next, the resin layer (21) laminated on the base layer (11) will be described.
As a constituent material, it is possible to use materials such as general-purpose resins, elastomers, and rubbers, but it is preferable to use a material having sufficient flexibility (elasticity) to sufficiently express the effects of the present invention. It is preferable to use an elastomer material or a rubber material.
Examples of the elastomer material include thermoplastic elastomers such as polyester, polyamide, polyether, polyurethane, polyolefin, polystyrene, polyacryl, polydiene, silicone-modified polycarbonate, and fluorine copolymer. . Examples of thermosetting include polyurethane, silicone-modified epoxy, and silicone-modified acrylic.
Examples of the rubber material include isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, butyl rubber, silicone rubber, chloroprene rubber, acrylic rubber, chlorosulfonated polyethylene, fluorine rubber, urethane rubber, and hydrin rubber. .
A material capable of obtaining performance is appropriately selected from the above-mentioned various elastomers and rubbers. In the present invention, when the spherical resin particle layer is formed on the surface of this material, it is more thermosetting than thermoplastic. The one is preferred. 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.

  To the selected material, a resistance adjusting agent for adjusting electrical characteristics, a flame retardant for obtaining flame retardancy, and materials such as an antioxidant, a reinforcing agent, a filler, and a vulcanization accelerator as necessary. Mixing appropriately included.

As the resistance adjuster for adjusting the electrical characteristics, the above-mentioned various materials can be applied. However, since carbon black, metal oxide, and the like impair flexibility, it is preferable to suppress the use amount, and the ionic conductive agent and the conductive agent are used. It is also effective to use a functional polymer. Moreover, you may use these together.
The resistance value of the resin layer is preferably adjusted so that the surface resistance is 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ and the volume resistance is 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm. .
The thickness of the resin layer 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.

<Spherical resin particles>
Next, the spherical resin particles formed on the surface of the resin layer will be described.
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.
Further, 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.
Moreover, as for the particle size, a volume average particle diameter is 1.0 micrometer-5.0 micrometers, and it is desirable that it is a monodisperse particle. The monodisperse particles referred to here do not mean particles with a single particle diameter but refer to those having a very sharp particle size distribution.
Specifically, it may have a distribution width of ± (average particle size × 0.5) μm or less.
When the particle size is less than 1.0 μm, the transfer performance effect due to the particles cannot be sufficiently obtained. On the other hand, when the particle size exceeds 5.0 μm, the surface roughness becomes large and the gap between the particles becomes large. Often fail to transfer well or result in poor cleaning.
Furthermore, since the particles are often insulative, 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 this potential during continuous image output.

<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. In this way, the spherical particles having a uniform particle diameter are independently and orderly arranged. Almost no overlap between the resin particles is observed.
The diameter of the cross section of each particle constituting the surface on the resin layer surface is preferably uniform, and specifically, the distribution width is preferably ± (average particle diameter × 0.5) μm or less.
In order to form this, it is preferable to use particles having a uniform particle size as much as possible, but the particle size distribution can be obtained by forming a surface by a method in which particles having a certain particle size can be selectively formed on the surface without using this. It is good also as a structure used as a width | variety.
The surface area occupied by these particles is preferably 60% or more. If it is less than 60%, the exposed portion of the resin portion is too much, and the toner comes into contact with the rubber, so that good transferability cannot be obtained.

Next, FIG. 3 shows a schematic enlarged cross-sectional view of the belt surface.
In the present invention, the spherical resin particles are in a form of being partially embedded in the resin layer, but the burying rate is preferably more than 50% and less than 100%, preferably 51% to 90%. It is more preferable. If it is less than 50%, particles are likely to be detached 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.
The burial rate is the rate of burial in the resin layer having a diameter in the depth direction of the particles, but the burial rate here means that all particles exceed 50% and do not reach 100%. Instead, the numerical value expressed by the average burial rate when viewed from a certain field of view should be more than 50% and less than 100%. However, when the embedding rate is 50%, in the cross-sectional observation with the electron microscope, the particles completely embedded in the resin layer are hardly observed (the number% of the particles completely embedded in the resin layer is the total number of particles). (5% or less).

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

<Belt surface preparation method>
After sufficiently cooling, the resin layer is subsequently laminated.
This resin layer can be formed on the base layer by injection molding, extrusion molding or the like, but in the present invention, it is effective to form by applying a resin coating solution.
In the resin coating liquid, liquid resin, liquid elastomer, liquid rubber, or the like can be used. A solution in which a solvent-soluble resin, elastomer, or rubber material is dissolved in a solvent can also be used as the coating solution. Here, a method of coating and forming on a base layer using a thermosetting liquid elastomer material will be described. The coating liquid containing at least a liquid thermosetting elastomer material is made uniform over the entire outer surface of the cylinder by a liquid supply device such as a nozzle or dispenser while slowly rotating the cylindrical metal mold like the base layer. Apply and cast (form a coating film).
Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached at a desired time, the rotation speed is maintained at a constant speed and the rotation is continued. Then, when sufficiently leveled, as shown in FIG. 4, a powder supply device (45) and a pressing member (43) are installed, and spherical particles are uniformly applied to the surface from the powder supply device (45) while rotating. The spherical particles applied to the surface are pressed with a pressing member (43) at a constant pressure. The pressing member (43) removes excess particles while embedding particles in the resin layer. In the present invention, in particular, since monodispersed spherical particles are used, it is possible to form a uniform single particle layer by a simple process of only the leveling process using such a pressing member.
The adjustment of the burying rate of the particles in the resin layer may be possible by other methods, but can be easily achieved by, for example, adjusting the pressing force of the pressing member (43). 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 1 mN at a viscosity of 100 to 100,000 mPa · s of the casting coating liquid. By setting the ratio in the range of / cm to 1000 mN / cm, the above-mentioned 50% <buried ratio <100% can be achieved relatively easily.
After the formation of a uniform particle layer, the resin layer is cured by heating at a predetermined temperature and a predetermined time while rotating to form a resin layer.
After sufficiently cooling, the entire base layer is detached from the mold to obtain a desired seamless belt (intermediate transfer belt).

The seamless belt manufactured by the above-described method performs, for example, a 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 recorded. It can be suitably used as an intermediate transfer belt of a so-called intermediate transfer type electrophotographic apparatus in which secondary transfer is collectively performed on a medium, and can form an electrophotographic apparatus (image forming apparatus) capable of forming a high-quality image.
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. 5 is a schematic diagram of a main part for explaining an image forming apparatus equipped with a seamless belt obtained by the manufacturing method according to the present invention as a belt member.
The intermediate transfer unit (500) including the belt member shown in FIG. 5 includes an intermediate transfer belt (501) that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt (501), there are a secondary transfer bias roller (605) as a secondary transfer charge applying means of the secondary transfer unit (600), and a belt cleaning blade (504) as an intermediate transfer body cleaning means. A lubricant application brush (505), which is a lubricant application member of the lubricant application means, is disposed so as to face each other.

  Further, position detection marks (not shown) are provided on the outer peripheral surface or inner peripheral surface of the intermediate transfer belt (501). However, on the outer peripheral surface side of the intermediate transfer belt (501), it is necessary to devise a position detection mark that avoids the passing area of the belt cleaning blade (504), which may be difficult to arrange. In this case, a position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt (501). The optical sensor (514) serving as a mark detection sensor is provided at a position between the primary transfer bias roller (507) and the belt driving roller (508) on which the intermediate transfer belt (501) is stretched.

  The intermediate transfer belt (501) includes a primary transfer bias roller (507), a belt driving roller (508), a belt tension roller (509), a secondary transfer counter roller (510), which are primary transfer charge applying means, and a cleaning device. It is stretched between the counter roller (511) and the feedback current detection roller (512). Each roller is made of a conductive material, and each roller other than the primary transfer bias roller (507) is grounded. The primary transfer bias roller (507) is controlled by a primary transfer power source (801) controlled by a constant current or a constant voltage so that the current or voltage is controlled to a predetermined magnitude according to the number of superimposed toner images. A bias is applied.

The intermediate transfer belt (501) is driven in the direction of the arrow by a belt drive roller (508) that is driven to rotate in the direction of the arrow by a drive motor (not shown).
The intermediate transfer belt (501) as the belt member is usually a semiconductor or an insulator and has a single-layer or multi-layer structure, but in the present invention, a seamless belt is preferably used, thereby improving durability. In addition, excellent image formation can be realized. In addition, 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), which is a secondary transfer means, is in contact with / separating means, which will be described later, with respect to the belt outer peripheral surface of a portion of the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510) It is comprised so that contact / separation is possible by the contact / separation mechanism. The secondary transfer bias roller (605) sandwiches the transfer paper (P) as a recording medium between the secondary transfer counter roller (510) and the intermediate transfer belt (501) stretched between the secondary transfer counter roller (510). A transfer bias having a predetermined current is applied by a secondary transfer power source (802) that is arranged and controlled at a constant current.

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

  In the color copying machine having such a configuration, when the image forming cycle is started, the photosensitive drum (200) is rotated in a counterclockwise direction indicated by an arrow by a driving motor (not shown), and the photosensitive drum (200) is rotated on the photosensitive drum (200). In addition, Bk (black) toner image formation, C (cyan) toner image formation, M (magenta) toner image formation, and Y (yellow) toner image formation are performed. The intermediate transfer belt (501) is rotated clockwise by the belt driving roller (508) as indicated by an arrow. As the intermediate transfer belt (501) rotates, the primary transfer of the Bk toner image, the C toner image, the M toner image, and the Y toner image is performed by the transfer bias by the voltage applied to the primary transfer bias roller (507). Finally, 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. 5, 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 charged uniformly, 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 adheres to the portion where the charge of the photosensitive drum (200) remains. 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 way is primary on the belt outer peripheral surface of the intermediate transfer belt (501) rotating at a constant speed while being in contact with the photosensitive drum (200). Transcribed. Some untransferred residual toner remaining on the surface of the photoreceptor drum (200) after the primary transfer is cleaned by the photoreceptor cleaning device (201) in preparation for reuse of the photoreceptor drum (200). Is done. On the photosensitive drum (200) side, the process proceeds to the 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. A C electrostatic latent image is formed on the surface of the body drum (200).

  Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the C electrostatic latent image reaches, the revolver developing unit (230) is rotated, and the C developer ( 231C) is set at the development position, and 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 portion 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 device (231K). Then, the next M developing device (231M) is moved to the developing position. This is also completed before the leading edge of the next Y electrostatic latent image reaches the developing position. Note that the M and Y image forming steps are the same as the Bk and C steps described above because the operations of reading color image data, forming an electrostatic latent image, and developing are the same as those described above.

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

  In this way, when the transfer paper (P) passes through the secondary transfer portion, the intermediate transfer belt (501) is transferred by the transfer bias generated by the voltage applied to the secondary transfer bias roller (605) by the secondary transfer power source (802). ) The four-color superimposed toner image on the top is transferred onto the transfer paper (P) at once (secondary transfer). This transfer paper (P) is conveyed along the transfer paper guide plate (601) and passes through a portion facing the transfer paper neutralization charger (606) comprising a static elimination needle disposed downstream of the secondary transfer portion. After being neutralized by this, the belt is conveyed toward the fixing device (270) by the belt conveying device (210) which is a belt component (see FIG. 1). Then, after the toner image is melted and fixed at the nip portion of the fixing rollers (271) and (272) of the fixing device (270), the transfer paper (P) is sent out of the apparatus main body by a discharge roller (not shown). Stacked face up on a copy tray (not shown). Note that the fixing device (270) may be configured to include a belt component if necessary.

  On the other hand, the surface of the photosensitive drum (200) after the belt transfer is cleaned by the photosensitive member cleaning device (201) and is uniformly discharged by the discharging lamp (202). The residual toner remaining on the outer peripheral surface of the intermediate transfer belt (501) after the toner image is secondarily transferred to the transfer paper (P) is cleaned by the belt cleaning blade (504). The belt cleaning blade (504) is configured to contact and separate at a predetermined timing with respect to the belt outer peripheral surface of the intermediate transfer belt (501) by a cleaning member separating and contacting mechanism (not shown).

  On the upstream side of the belt cleaning blade (504) in the moving direction of the intermediate transfer belt (501), a toner seal member (502) contacting and separating from the belt outer peripheral surface of the intermediate transfer belt (501) is provided. Yes. The toner seal member (502) receives the falling toner that has dropped from the belt cleaning blade (504) during cleaning of the residual toner, and prevents the falling toner from scattering on the transfer path of the transfer paper (P). It is preventing. 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 belt outer peripheral surface of the intermediate transfer belt (501) from which the residual toner has been removed in this way. The lubricant (506) is made of, for example, a solid body such as zinc stearate, and is disposed so as to come into contact with the lubricant application brush (505). Further, residual charges remaining on the outer peripheral surface of the intermediate transfer belt (501) are removed by a neutralizing bias applied by a belt neutralizing brush (not shown) in contact with the outer peripheral surface of the intermediate transfer belt (501). Here, the lubricant application brush (505) and the belt neutralizing brush are brought into and out of contact with the outer peripheral surface of the intermediate transfer belt (501) at a predetermined timing by a contact / separation mechanism (not shown). It has become.

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

In the above-described embodiment, the copying machine including only one photosensitive drum (200) has been described. However, the present invention is not limited to a plurality of photosensitive members, for example, as shown in a schematic diagram of a main part in FIG. The present invention can also be applied to an image forming apparatus in which a drum is arranged side by side along one intermediate transfer belt made of a seamless belt.
FIG. 6 shows four drums including four photosensitive drums (21BK), (21Y), (21M), and (21C) for forming toner images of four different colors (black, yellow, magenta, and cyan). 1 shows an example of the configuration of a type digital color printer.

In FIG. 6, 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 the image writing unit (12). Send to. The image writing unit (12) is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group, and corresponds to each color signal described above. There are four writing optical paths, and image carriers (photoconductors) (21BK), (21M), (21Y), and (21C) provided for each color of the image forming unit (13) according to the respective color signals. Perform image writing.

The image forming unit (13) is a photoconductor (21BK), (21M), (21Y) which is an image carrier for black (BK), magenta (M), yellow (Y), and cyan (C). ), (21C).
As each photoconductor for each color, an OPC photoconductor is usually used. Around each of the photosensitive members (21BK), (21M), (21Y), and (21C), there are a charging device, a laser beam exposure unit from the writing unit (12), and each color of black, magenta, yellow, and cyan Developing devices (20BK), (20M), (20Y), (20C), primary transfer bias rollers (23BK) as primary transfer means, (23M), (23Y), (23C), cleaning devices ( (Not shown), and a photosensitive member neutralizing device (not shown) are provided. The developing devices (20BK), (20M), (20Y), and (20C) use a two-component magnetic brush developing system. The intermediate transfer belt (22), which is a belt component, includes the photosensitive members (21BK), (21M), (21Y), and (21C) and the primary transfer bias rollers (23BK), (23M), and (23Y). , (23C), and the toner images of the respective colors formed on the respective photoreceptors are sequentially superimposed and transferred. In FIG. 6, toner images are formed on the intermediate transfer belt in the order of (23C), (23Y), (23M), and (23BK).

  On the other hand, the transfer paper (P) is fed from the paper feeding section (14) and then carried on the transfer conveyance belt (50), which is a belt constituting section, via the registration rollers (16). When the intermediate transfer belt (22) and the transfer conveying belt (50) come into contact with each other, the toner image transferred onto the intermediate transfer belt (22) is transferred to a secondary transfer bias roller (60) as a secondary transfer unit. ) For secondary transfer (collective transfer). Thereby, a color image is formed on the transfer paper (P). The transfer paper (P) on which the color image is formed is conveyed to the fixing device (15) by the transfer conveying belt (50). After the image transferred by the fixing device (15) is fixed, the transfer paper (P) is removed from the printer main body. To be discharged.

Residual toner remaining on the intermediate transfer belt (22) without being transferred during the secondary transfer is removed from the intermediate transfer belt (22) by the belt cleaning member (25).
As the cleaning member (25), a blade member such as the apparatus shown in FIG. 5 can be used. However, when the intermediate transfer belt has a sufficiently flexible resin layer formed in a certain thickness or more as in the present invention, The blade cannot be pressed sufficiently and cannot be cleaned well.
In this case, it is preferable to use a method in which the cleaning member is a conductive roller or a conductive brush member, which is in contact with the intermediate transfer belt, and a voltage is applied to effectively remove the toner by this electric field action. . A lubricant application device (27) is disposed on the downstream side of the belt cleaning member (25) as necessary. 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.

〔toner〕
In such an electrophotographic apparatus, a toner having a small particle diameter, specifically, a volume average particle diameter of 3 to 7 μm is used as a toner for obtaining a high-definition image.
When such a small particle size toner is used, there is a strong tendency to include a lot of ultrafine toner of 2 μm or less. Such fine toner has a large charged charge, poor transferability and cleanability, and poorly cleaned toner, which is repeatedly used, forms a film on the surface of the intermediate transfer belt and causes a decrease in transfer performance. . In the present invention using the intermediate transfer belt having the configuration described above, if there is a large amount of extremely fine toner of 2 μm or less, the extremely fine toner is sandwiched between the irregularities constituting the surface of the intermediate transfer belt, resulting in poor transfer and poor cleaning. Will cause. Therefore, it is desirable that this very fine toner of 2 μm or less be 10% by number or less.
Such a toner may be classified and manufactured by using a conventional pulverization method so as to satisfy the above conditions. However, the pulverization method has a volume average particle diameter of 3 to 7 μm, and The production efficiency of extremely fine toners of 2 μm or less of 10% by number or less is very low, so that it is preferable to produce them by a chemical polymerization method excellent in producing fine particles having a uniform particle size.

  In addition, it is preferable to use one having a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) in the range of 1.00 to 1.30. Such toner has a uniform particle size distribution, and since the charge amount distribution of each toner particle is also uniform, the electric field cleaning of the intermediate transfer belt described with reference to FIG. It can act more effectively.

<Measurement of toner particle size and particle size distribution>
The average particle size and the particle size distribution of the toner are determined by the car Coulter counter method.
Examples of the measuring device for the particle size distribution of the toner particles include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, measurement was performed using a Coulter Counter TA-II type connected to an interface (Nikka Giken) that outputs number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC).
The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution.
Here, the electrolytic solution is prepared by preparing an about 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used.
Here, 2 to 20 mg of a measurement sample is further added.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.
The volume-based volume average particle diameter (Dv) obtained from the volume distribution according to the present invention and the number average particle diameter (Dn) obtained from the number distribution and the ratio Dv / Dn are obtained.

<Method for measuring particles of 2 μm or less>
It is measured by a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation).
In the measurement method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant in 100 to 150 ml of water from which impurities have been previously removed, and a measurement sample is further added in an amount of 0.1 to 0. Add about 5g. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic dispersion for 1 to 3 minutes, and the shape and distribution of the toner can be measured by the above apparatus with the dispersion concentration being 3000 to 10,000 / μl. From this, the ratio of the number of particles of 2 μm or less to the total number of particles is determined.

  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. Are also within the scope of the present invention.

[Production of Intermediate Transfer Belt A]
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.

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.

"Making an elastic layer on a base layer"
Each material shown below was blended and kneaded with a kneader to prepare a rubber composition.
Acrylic rubber (Nippon ZEON Co., Ltd. Nipol AR12) 100 parts by weight Stearic acid (by NOF Co., Ltd. Bead stearic acid Tsubaki) 1 part by weight Red phosphorus (Rin Chemical Industry Co., Ltd. Nova Excel 140F) 10 parts by weight Aluminum hydroxide (Showa Denko Co., Ltd. Heidilite H42M) 60 parts by weight crosslinking agent (Du Pont Dow Elastomer Japan Diak.No1 (hexamethylenediamine carbamate))
0.6 parts by weight crosslinking accelerator (VULCOFAC ACT55 (70% 1,8-diazabicyclo (5,4,0) undecene-7 and dibasic acid salt, 30% amorphous silica) manufactured by Safari Alcan)
0.6 parts by weight conductive agent (QAP-01 (tetrabutylammonium perchlorate) manufactured by Nippon Carlit Co., Ltd.)
0.3 parts by weight Next, the rubber composition thus obtained was dissolved in an organic solvent (MIBK: methyl isobutyl ketone) to prepare a rubber solution having a solid content of 35 wt%. 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. Thereafter, the cylindrical support coated with the rubber paint was put into a hot air circulating dryer while rotating as it was, heated to 90 ° C. at a temperature rising rate of 4 ° C./min, and heated for 30 minutes.
Thereafter, the surface is taken out from the dryer and cooled, and on this surface, using the method of FIG. 4, acrylic resin spherical particles (Techpolymer MBX-SS series (volume average particle size 1 μm product); Sekisui Plastics as spherical resin particles; (Industry) was evenly applied to the surface, and the pressing member of the polyurethane rubber blade was pressed with a pressing force of 100 mN / cm to be fixed to the resin layer. Thereafter, it was put into the hot air circulating dryer again, heated to 170 ° C. at a temperature rising rate of 4 ° C./min, and heat-treated for 60 minutes, whereby an intermediate transfer belt A was obtained.
When the cross section of the belt was observed with an electron microscope, the embedding ratio of the particles in the resin layer was 65%.

[Production of intermediate transfer belt B]
An intermediate transfer belt B was obtained in the same manner except that the spherical resin particles in the intermediate transfer belt A were replaced with silicone resin particles (X-52-854 (volume average particle system 0.8 μm product); Shin-Etsu Chemical).
When the cross section of the belt was observed with an electron beam microscope, the burying rate of the particles in the resin layer was 53%.

[Production of intermediate transfer belt C]
An intermediate transfer belt C was obtained in the same manner except that the spherical resin particles in the intermediate transfer belt A were replaced with silicone resin particles (Tospearl 120 (volume average particle system 2.0 μm product); Momentive Performance Materials).
When the cross section of this belt was observed with an electron microscope, the embedding ratio of particles in the resin layer was 75%.

[Manufacture of intermediate transfer belt D]
An intermediate transfer belt D was obtained in the same manner except that the spherical resin particles in the intermediate transfer belt A were replaced with silicone resin particles (Tospearl 2000B (volume average particle system 6.0 μm product); Momentive Performance Materials).
When the cross section of the belt was observed with an electron microscope, the burying rate of the particles in the resin layer was 78%.

[Production of intermediate transfer belt E]
An intermediate transfer belt E was obtained except that the spherical resin particles in the intermediate transfer belt A were not used.

[Manufacture of intermediate transfer belt F]
An intermediate transfer belt F was obtained except that the spherical resin particles in the intermediate transfer belt A were replaced with silicone resin amorphous particles (Tospearl 240 (volume average particle system 2.0 μm product); Momentive Performance Materials). .
When the cross section of the belt was observed with an electron microscope, the embedding of the particles could be observed, but because of the irregular shape, the degree of embedding by the particles was uneven, and a clear embedding rate could not be obtained.

[Preparation of pulverized toner I]
Binder resin Polyester resin 70 parts Styrene-acrylic resin 30 parts Colorant carbon black 10 parts Charge control agent Fe-containing azo dye 2 parts Release agent Carnauba wax 5 parts are mixed in a Henschel mixer and then 140 ° C. The mixture was melt-kneaded in a biaxial kneader heated at a constant temperature.
The kneaded product was cooled with water, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then repeatedly classified using an air classifier to obtain a base toner.
To 100 parts of this base toner, 1.2 parts of additive titania and 0.5 parts of silica were mixed with a Henschel mixer and the peripheral speed of the stirring blade was 25 m / sec. The mixture was mixed for 100 seconds, and then further sieved with a sieve having an opening of 150 μm to obtain toner I.
The volume average diameter DV, number average diameter Dn, DV / Dn, and number% of 2 μm or less of this toner were as follows.
Volume average diameter DV = 6.8 μm, number average diameter Dn = 5.4 μm, DV / Dn = 1.26, ratio of 2 μm or less = 9.6 number%

[Preparation of pulverized toner II]
The pulverized toner I was prepared in the same manner by increasing the flow velocity of the jet air flow of the pulverizer.
The volume average diameter DV, number average diameter Dn, DV / Dn, and number% of 2 μm or less of this toner were as follows.
Volume average diameter DV = 6.0 μm, number average diameter Dn = 4.6 μm, DV / Dn = 1.30, ratio of 2 μm or less = 12.5% by number

[Preparation of pulverized toner III]
It was produced in the same manner except that the number of classifications in the pulverized toner I was reduced.
The volume average diameter DV, number average diameter Dn, DV / Dn, and number% of 2 μm or less of this toner were as follows.
Volume average diameter DV = 6.9 μm, number average diameter Dn = 5.1 μm, DV / Dn = 1.35, ratio of 2 μm or less = 9.9 number%

(Preparation of polymerization toner IV)
229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propion oxide 3-mole adduct, 208 parts of terephthalic acid, 46 parts of adipic acid and dibutyltin oxide 2 parts were added and reacted at 230 ° C. under normal pressure for 8 hours.
Next, after reacting under reduced pressure of 10 to 15 mmHg for 5 hours, 44 parts of trimellitic anhydride was added to the reaction vessel and reacted at 180 ° C. for 2 hours under normal pressure to synthesize an unmodified polyester resin. .
The obtained unmodified polyester resin had a number average molecular weight of 2500, a weight average molecular weight of 6700, a glass transition temperature of 43 ° C., and an acid value of 25 mgKOH / g.
1200 parts of water, 540 parts of carbon black Printex 35 (manufactured by Dexa; DBP oil absorption = 42 ml / 100 mg, pH = 9.5) and 1200 parts of unmodified polyester resin were mixed using a Henschel mixer (manufactured by Mitsui Mining). .
The resulting mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then rolled and cooled, and pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to prepare a master batch.

In a reaction vessel equipped with a stirrer and a thermometer, 378 parts of unmodified polyester resin, 110 parts of carnauba wax, 22 parts of salicylic acid metal complex E-84 (manufactured by Orient Chemical Co., Ltd.) and 947 parts of ethyl acetate were charged and stirred. The temperature was raised to 80 ° C., held at 80 ° C. for 5 hours, and then cooled to 30 ° C. over 1 hour.
Next, 500 parts of a master batch and 500 parts of ethyl acetate were charged into the reaction vessel and mixed for 1 hour to obtain a raw material solution.

  1324 parts of the resulting raw material solution was transferred to a reaction vessel, and filled with 80% by volume of 0.5 mm zirconia beads using a bead mill, Ultraviscomil (manufactured by Imex Co., Ltd.). 3 passes under the condition of 6 m / sec. I. Pigment Red and carnauba wax were dispersed to obtain a wax dispersion.

Next, 1324 parts of a 65 wt% ethyl acetate solution of unmodified polyester resin was added to the wax dispersion.
A layered inorganic mineral montmorillonite (Clayton HY Southern Clay Products) at least partially modified with an ammonium salt having a polyoxyethylene group was added to 200 parts of the dispersion obtained by one pass using Ultraviscomil under the same conditions as above. 3 parts) was added. K. The mixture was stirred for 30 minutes using a homodisper (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a toner material dispersion.

In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 8 hours under normal pressure.
Next, it was made to react under reduced pressure of 10-15mHg for 5 hours, and the intermediate polyester resin was synthesize | combined.
The obtained intermediate polyester resin had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, a glass transition temperature of 55 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 51 mgKOH / g.

Next, 410 parts of the intermediate polyester resin, 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are charged into a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Was synthesized.
The free isocyanate content of the obtained prepolymer was 1.53% by weight.
In a reaction vessel equipped with a stir bar and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize a ketimine compound.
The amine value of the obtained ketimine compound was 418 mgKOH / g.

  In a reaction vessel, 749 parts of a dispersion of toner material, 115 parts of a prepolymer and 2.9 parts of a ketimine compound are charged and mixed at 5,000 rpm for 1 minute using a TK homomixer (manufactured by Tokushu Kika). A mixture was obtained.

In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of water, 11 parts of reactive emulsifier (sodium salt of sulfuric acid ester of methacrylic acid ethylene oxide adduct), Eleminol RS-30 (manufactured by Sanyo Chemical Industries), styrene 83 Parts, 83 parts of methacrylic acid, 110 parts of butyl acrylate and 1 part of ammonium persulfate were stirred at 400 rpm for 15 minutes to obtain an emulsion. The emulsion was heated, heated to 75 ° C. and reacted for 5 hours.
Next, 30 parts of a 1% by weight aqueous ammonium persulfate solution was added and aged at 75 ° C. for 5 hours to prepare a resin particle dispersion.

990 parts of water, 83 parts of resin particle dispersion, 37 parts of a 48.5% by weight aqueous solution of dodecyl diphenyl ether disulfonate, Eleminol MON-7 (manufactured by Sanyo Kasei Kogyo Co., Ltd.), 1% by weight aqueous solution of sodium carboxymethylcellulose polymer dispersant 135 parts of BS-H-3 (Daiichi Kogyo Seiyaku Co., Ltd.) and 90 parts of ethyl acetate were mixed and stirred to obtain an aqueous medium.
To 1200 parts of the aqueous medium, 867 parts of the oil phase mixed liquid was added and mixed for 20 minutes at 13000 rpm using a TK homomixer to prepare a dispersion (emulsified slurry).
Next, the emulsified slurry was charged into a reaction vessel equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was performed at 45 ° C. for 4 hours to obtain a dispersed slurry.

After 100 parts by weight of the dispersion slurry was filtered under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, mixed at 12000 rpm for 10 minutes using a TK homomixer, and then filtered.
To the obtained filter cake, 10 wt% hydrochloric acid was added to adjust the pH to 2.8, and the mixture was mixed at 12000 rpm for 10 minutes using a TK homomixer, followed by filtration.
Furthermore, 300 parts of ion-exchanged water was added to the obtained filter cake, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice to obtain a final filter cake.
The obtained final filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner mother particles.
To 100 parts of the obtained toner base particles, 1.0 part of hydrophobic silica as an external additive and 0.5 part of hydrophobized titanium oxide are added and mixed using a Henschel mixer (Mitsui Mining Co., Ltd.). The toner was manufactured.
This is designated as [Polymerized toner IV].
The volume average diameter DV, number average diameter Dn, DV / Dn, and number% of 2 μm or less of this toner were as follows.
Volume average diameter DV = 5.0 μm, number average diameter Dn = 4.3 μm, DV / Dn = 1.16, ratio of 2 μm or less = 5.4 number%

As shown in Table 1, the intermediate belt A and the toner I were mounted on the electrophotographic apparatus of FIG. 6 and the following various evaluations were performed.
(I) Measurement of transfer rate As the transfer paper, paper having a Japanese paper-like pattern on the surface (Resac 66 with a continuous weight of 175 kg) was used, and a blue solid image (two colors of cyan and magenta) The amount of image toner on the intermediate transfer belt before transferring to paper and the amount of toner remaining on the intermediate transfer belt after transferring to paper were measured to calculate the transfer rate.
As the transfer rate, 80% or more is acceptable, and 90% or more is more preferable.
(II) Measurement of transfer rate at the time of continuous image output of 10,000 sheets After outputting 10,000 continuous images of test charts, the test was stopped and the transfer rate was measured according to the method of (I) above.
(III) Image evaluation at the time of continuous image output of 10,000 sheets An abnormal image at the time of continuous image output of 10,000 continuous test charts was confirmed.
The results are shown in Table 1.

  As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt B and toner I were used, and the following various evaluations were performed. The results are shown in Table 1.

  As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt C and toner I were used, and the following various evaluations were performed. The results are shown in Table 1.

  As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt D and the toner I were used, and the following various evaluations were performed. The results are shown in Table 1.

[Comparative Example 1]
As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt E and toner I were used, and the following various evaluations were performed. The results are shown in Table 1.

[Comparative Example 2]
As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt F and the toner I were used, and the following various evaluations were performed. The results are shown in Table 1.

[Comparative Example 3]
As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt C and toner II were used, and the following various evaluations were performed. The results are shown in Table 1.

  As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt C and toner III were used, and the following various evaluations were performed. The results are shown in Table 1.

  As shown in Table 1, it was mounted on the electrophotographic apparatus of FIG. 6 in the same manner as in Example 1 except that the intermediate belt C and toner IV were used, and the following various evaluations were performed. The results are shown in Table 1.

  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 in FIG. 1)
11 Base layer 12 Resin layer 13 Particles (reference numeral in FIG. 2)
21 Resin part 22 Particle part (symbol of FIG. 3)
31 resin layer 32 particles (reference numeral in FIG. 4)
41 Die drum 42 Belt 43 coated with base layer and resin layer Pressing member 44 Particle 45 Powder supply device (reference numeral in FIG. 5)
L Laser beam P Transfer paper 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photosensitive drum cleaning device 202 Static elimination lamp 203 Charger charger 204 Potential sensor 205 Image density sensor 210 Belt conveying device 230 Revolver developing unit 231Y Y developing device 231K Bk developing device 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. 6) )
P transfer paper 10 printer main 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 Driven roller 27 Lubricant coating device 50 Transfer conveyor belt 60 Secondary transfer bias roller 70 Static elimination roller

JP-A-9-230717 JP 2002-162767 A JP 2004-354716 A JP 2007-328165 A JP 2009-75154 A Japanese Patent Application No. 2010-009871

Claims (5)

A toner image obtained by developing the latent image formed on the latent image carrier with toner is primarily transferred onto the intermediate transfer member, and the primary transferred image on the intermediate transfer member is secondarily transferred onto the transfer material. In an electrophotographic apparatus including a step of cleaning residual toner remaining on an intermediate transfer belt, the intermediate transfer member has a single layer of independent spherical resin particles on a base layer containing a polyimide resin or a polyamideimide resin. has a resin layer in which a concavo-convex shape is formed of a single particle layer that by the embedded the particles implantation ratio less than 100% more than 50% in the depth direction in one state, the spherical resin particles Is a monodisperse particle having a distribution width of ± (average particle diameter of spherical resin fine particles × 0.5) or less, wherein the resin forming the resin layer contains a thermosetting elastomer or rubber material, and The electrophotographic equipment The electrophotographic apparatus is characterized in that the toner used for the setting has a volume average particle diameter of 3 to 7 μm and 10 μ% or less of particles of 2 μm or less.   The ratio (Dv / Dn) of the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner particles of the toner is in the range of 1.00 to 1.30. The electrophotographic apparatus according to the description.   The electrophotographic apparatus according to claim 1, wherein the toner is a toner produced by a polymerization method.   4. The electrophotographic apparatus according to claim 1, wherein the spherical resin particles on the surface of the intermediate transfer member are silicone resin particles having an average particle diameter of 1.0 μm to 5.0 μm. Wherein the step of cleaning the intermediate transfer member, an electrophotographic apparatus according to any one of claims 1 to 4, characterized in that cleaning by the contact member having means for applying an electric field.

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