JP5982792B2 - Belt for image forming apparatus 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. In addition, the intermediate transfer belt is laid out over a wide area of the apparatus, and a high voltage is applied for 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 elastic layer is laminated on a base layer have been proposed.

  Patent Document 1 (Japanese Patent No. 3248455) proposes a structure in which an intermediate layer made of a blend rubber of NBR and EPDM and a surface layer made of a fluororubber-modified resin are laminated on a polyimide base layer. Patent Document 2 (Japanese Patent Laid-Open No. 2009-223282) discloses a structure in which an elastic layer made of an epoxy-modified silicone resin is laminated on a polyimide base layer. A belt in which an elastic layer made of urethane rubber and a surface layer made of urethane resin are laminated on a PVdF base layer has been proposed.

  However, the actual situation is that sufficient transfer cannot be realized on a sheet with large unevenness in any of the configurations.

  The present invention has been made in view of the above prior art, has sufficient flexibility to follow a transfer medium with large unevenness, can achieve a high transfer rate irrespective of the transfer medium, and has excellent durability. An object of the present invention is to realize a belt for an image forming apparatus used in an electrophotographic apparatus having high image quality and high durability.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following (1) to (6).
(1) “A seamless belt for an electrophotographic apparatus in which an elastic layer made of rubber or elastomer having a concavo-convex shape of spherical fine particles is formed on at least a base layer, the elastic layer containing acrylic rubber and nitrile rubber A seamless belt for an electrophotographic apparatus, characterized by:
(2) “The image forming apparatus according to (1), wherein the image forming apparatus is an intermediate transfer body onto which a toner image obtained by developing a latent image formed on an image carrier with toner is transferred. Belt ";
(3) “Seamless belt for electrophotographic apparatus according to item (1) or (2), wherein the nitrile rubber has a carboxyl group”;
(4) The electrophotography according to any one of (1) to (3) above, wherein the acrylic rubber component and the nitrile rubber component are in a weight ratio of 90/10 to 60/40. Seamless belt for equipment ”;
(5) “Seamless belt for electrophotographic apparatus according to any one of items (1) to (4), wherein the intermediate transfer member has a micro rubber hardness at 25 ° C. of 35 or less”:
(6) “The 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. Then, in the electrophotographic apparatus having a step of cleaning the transfer residual toner remaining on the intermediate transfer member, the intermediate transfer member is the seamless belt according to any one of the above items (2) to (5). An electrophotographic apparatus characterized by that. "

  As will be apparent from the following detailed and specific description, according to the present invention, seamlessly mounted on an electrophotographic apparatus having high image quality and high durability capable of realizing high transfer performance regardless of the type and surface properties of the transfer medium. A belt and an intermediate transfer member can be realized.

FIG. 3 is a schematic diagram illustrating a layer configuration example of an intermediate transfer belt in the present 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. It is a schematic diagram of the particle | grain embedding apparatus to the belt elastic layer surface in this invention.

  As described above, the belt for an electrophotographic apparatus according to the present invention has a configuration in which an elastic layer is formed on at least a base layer. The shape may be a drum shape or a belt shape, but a belt shape is generally used. Hereinafter, the intermediate transfer belt will be mainly described.

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 an example of a layer structure of an intermediate transfer belt that is preferably used in the present invention.
However, it is not limited to this configuration.
As a constitution, a flexible elastic layer (12) is laminated on a rigid base layer (11) capable of obtaining relatively flexibility, and toner releasability is provided on the outermost surface of the elastic layer (12). In order to impart, spherical fine particles (13) are buried on the surface, and a concave-convex shape is formed.

<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. 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. The amount is set to 10 ¹² Ω · cm, but 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.

  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.

<Elastic layer>
Next, the elastic 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. .
From the various elastomers and rubbers described above, materials capable of obtaining performance are appropriately selected. In the present invention, acrylic rubber and nitrile rubber are particularly preferably selected and used in combination.

The intermediate transfer belt is required to have flame retardancy, but acrylic rubber can exhibit sufficient flexibility even if it contains a flame retardant, and has excellent heat resistance and ozone resistance. The intermediate transfer belt is preferable. However, a low-hardness material having sufficient flexibility is inferior in rubber elasticity and brittle, so that it is easily damaged when a load such as strong rubbing in an electrophotographic apparatus is applied. In particular, there is a drawback that the casing and the end seal portion of the contact member are easily damaged by rubbing, which causes a problem in durability. In this invention, it discovered that the said problem was solved by mixing a nitrile rubber with this.
Nitrile rubber is excellent in rubber elasticity and can be improved by mixing appropriately, but the mixing amount is preferably 90/10 to 60/40 as the weight ratio of acrylic rubber to nitrile rubber. If the amount of nitrile rubber is too small, the improvement effect is poor. On the other hand, when there is too much nitrile rubber, the ozone resistance is poor and the durability in electrophotography is poor.

The elastic layer preferably has a micro rubber hardness at 25 ° C. of 35 or less.
If it exceeds 35, the transfer performance to the surface of transfer paper with large irregularities such as embossed paper becomes insufficient.

It is more preferable to use a nitrile rubber containing a carboxy group.
Carboxy group-containing nitrile rubber can be vulcanized with an amine compound, and can be co-vulcanized with acrylic rubber. For this reason, a further sufficient effect can be obtained.

As an acrylic rubber, for example, Nipol AR series manufactured by Nippon Zeon Co., Ltd.
Examples of the nitrile rubber include N series manufactured by JSR, Nipol and Zetpol series manufactured by Nippon Zeon, and Terban series manufactured by LANXESS. In particular, carboxy group-containing compounds include Nipol 1072J, NipolDN631, NipolNX775, and TherbanXT.

  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 elastic layer is preferably adjusted so that the surface resistance is 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □, and the volume resistance is 1 × 10 ⁶ to 1 × 10 ¹² Ω · cm. .
The thickness of the elastic 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, such being undesirable. 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.
In addition, as the flame retardant, halogen-based materials are not preferable due to the recent increase in environmental awareness, and a system using red phosphorus, metal hydroxide, metal oxide, or the like in combination is preferable.

Further, spherical particles formed on the surface of the elastic 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 be one having an average particle diameter ± (average particle diameter × 0.5) μm or less.
If the particle size is less than 1.0 μm, the effect of the transfer performance by the particles cannot be sufficiently obtained. On the other hand, if the particle size exceeds 5.0 μm, the surface roughness becomes large and the gap between the particles becomes large. Problems such as poor transfer and poor cleaning occur.
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.

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 rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is formed, the mold is transferred to a heating furnace (firing furnace) capable of high-temperature processing, and the temperature is raised stepwise, and finally high-temperature heat processing (firing is performed at about 250 ° C. to 450 ° C. And sufficiently imidizing or polyimidizing the polyimide resin precursor or the polyamideimide resin precursor.

After sufficiently cooling, the elastic layer is subsequently laminated.
The elastic layer can be formed on the base layer by injection molding, extrusion molding, or the like. However, in the present invention, it is effective to form the elastic layer by applying a coating solution in which rubber is dissolved in a solvent.
A coating liquid obtained by dissolving an unvulcanized compound of rubber mixed with acrylic rubber and nitrile rubber in an organic solvent, like a base layer, while slowly rotating a cylindrical metal mold, nozzles and dispensers Application and casting (formation of a coating film) is performed so as to be uniform over the entire outer surface of the cylinder using a liquid supply apparatus such as
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 elastic 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 burial rate of the particles in the elastic 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. 2 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. 2 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. 2, 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. 2). 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 illustrated 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. 3 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. 3, 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.

Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to these examples, and those examples may be appropriately modified without departing from the gist of the present invention. It is within the scope of the present invention. However, Examples 1-4 and Example 7 are read as reference examples.

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.

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./NipolAR12) 90 parts by weight Stearic acid (by Nippon Oil 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 Electric Co., Ltd. Heidilite H42M) 40 parts by weight Crosslinker (DuPont Dow Elastomer Japan Diak.No1
(Hexamethylenediamine carbamate)) 0.6 parts by weight Cross-linking accelerator (Safic alcan VULCOFAC ACT55
(70% 1,8-diazabicyclo (5,4,0) undecene-7 salt with dibasic acid,
30% amorphous silica)) 0.6 parts by weight Nitrile rubber (rubber-like copolymer of acrylonitrile and butadiene)
(Nippon ZEON Co., Ltd./Nipol 1042) 10 parts by weight sulfur (Tsurumi Chemical Industries 200mesh sulfur) 0.1 parts by weight zinc oxide (Zojang Chemical Industry Zinc Hua 2 types) 0.3 parts by weight Vulcanization accelerator (Emerging Ouchi) Chemical Industry / Noxeller CZ) 0.1 parts by weight Conductive agent (Nippon Carlit Co., Ltd. QAP-01
(Tetrabutylammonium perchlorate) 0.3 parts by weight Next, the rubber composition thus obtained was dissolved in an organic solvent (MIBK: methyl isobutyl ketone) to prepare a rubber solution having a solid content of 35 wt%. 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 of the dryer and cooled, and on this surface, using the method of FIG. 4, silicone spherical particles (Tospearl 120 (volume average particle size 2 μm product); Momentive Materials) are uniformly applied to the surface as spherical fine particles. The pressing member of the polyurethane rubber blade was pressed with a pressing force of 100 mN / cm and fixed to the elastic 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%.

(Example 2)
60 parts by weight of acrylic rubber (Nippon Zeon Co., Ltd./NipolAR12) and 90 parts by weight of nitrile rubber (rubber copolymer of acrylonitrile and butadiene; Nippon Zeon Co., Ltd./Nipol 1042) in the rubber composition of Example 1 were each 60 parts. The intermediate transfer belt B was obtained in the same manner except that the amount was 40 parts by weight.

(Example 3)
90 parts by weight of acrylic rubber (Nippon Zeon Corporation / NipolAR12) and nitrile rubber (rubber copolymer of acrylonitrile and butadiene) of the rubber composition in Example 1
(ZEON CORPORATION / Nipol 1042) An intermediate transfer belt C was obtained in the same manner except that 10 parts by weight were 96 parts by weight and 4 parts by weight, respectively.

Example 4
90 parts by weight of an acrylic rubber (Nippon Zeon Corporation / NipolAR12) and 50 parts by weight of a nitrile rubber (rubber copolymer of acrylonitrile and butadiene: Nippon Zeon Corporation / Nipol 1042) in Example 1 were each 50 parts. An intermediate transfer belt D was obtained in the same manner except that the amount was 50 parts by weight.

(Example 5)
The intermediate transfer belt is the same as in Example 1, except that the nitrile rubber (rubber copolymer of acrylonitrile and butadiene: Nippon Zeon Co., Ltd./Nipol 1042) is replaced with a carboxyl group-containing hydrogenated nitrile rubber (LANXESS Co./TherbanXT). E was obtained.

(Example 6)
The intermediate transfer belt is the same as in Example 2, except that the nitrile rubber (rubber-like copolymer of acrylonitrile and butadiene: Nippon Zeon Co., Ltd./Nipol 1042) is replaced with a carboxyl group-containing hydrogenated nitrile rubber (LANXESS Co./TherbanXT). F was obtained.

(Example 7)
The intermediate transfer belt is the same as in Example 3, except that the nitrile rubber (rubber-like copolymer of acrylonitrile and butadiene: Nippon Zeon Co., Ltd./Nipol 1042) is replaced with a carboxyl group-containing hydrogenated nitrile rubber (LANXESS Co./TherbanXT). G was obtained.

(Example 8)
The intermediate transfer belt is the same as in Example 4 except that the nitrile rubber (rubber copolymer of acrylonitrile and butadiene: Nippon Zeon Co., Ltd./Nipol 1042) is replaced with a carboxyl group-containing hydrogenated nitrile rubber (LANXESS Co./TherbanXT). H was obtained.

(Comparative Example 1)
An intermediate transfer belt X was obtained in the same manner as in Example 1 except that the elastic layer was changed to the following.
Acrylic rubber (Nippon ZEON Co., Ltd., Nipol AR12) 100 parts by weight Stearic acid (by NOF Corporation Beads stearic acid Tsubaki) 1 part by weight Red phosphorus (Rin Chemical Industry Co., Ltd. Nova Excel 140F) 10 parts by weight Hydroxylation 50 parts by weight of aluminum (Heidilite H42M manufactured by Showa Denko KK) 0.6 parts by weight of cross-linking accelerator (VULCOFAC ACT55 manufactured by Safic alcan) % 1,8-diazabicyclo (5,4,0) undecene-7 salt with dibasic acid, 30% amorphous silica) 0.6 parts by weight Conductive agent (Nippon Carlit Co., Ltd. QAP-01: Perchlorine Tetrabutylammonium acid)) 0.3 parts by weight

(Comparative Example 2)
An intermediate transfer belt Y was obtained in the same manner as in Example 1 except that the elastic layer was changed to the following.
Nitrile rubber (Rubber copolymer of acrylonitrile and butadiene: Nippon Zeon Co., Ltd./Nipol 1042) 100 parts by weight Sulfur (Tsurumi Chemical Industry 200mesh sulfur) 1 part by weight Zinc oxide (Zohua Chemical Industry Zinc Hua 2 types) 3 parts by weight Part Vulcanization Accelerator (Ouchi Shinsei Chemical Industry / Noxeller TS) 2 parts by weight Vulcanization Accelerator (Ouchi New Chemical Industry / Noxeller CZ) 1 part by weight Processing aid; (Kao / Lunac S-20) 1 part by weight Chlorinated paraffin (Tosoh / Toyoparax 150) 60 parts by weight Zinc hydroxystannate; (Mizusawa Chemical Industry / ALCANEX / ZHSF) 20 parts by weight

<Measurement of hardness of various intermediate transfer belts>
The hardness of various intermediate transfer belts was measured with a micro rubber hardness meter (MD-1; polymer meter).
The measurement was carried out in an environment of 25 ° C., and each intermediate transfer belt was also fully conditioned under this temperature environment.

<Evaluation in electrophotographic apparatus>
The above intermediate transfer belt and toner were mounted on the electrophotographic apparatus shown in FIG.
(I) Observation of images on uneven paper As the transfer paper, paper with a Japanese paper-like pattern on the surface (Rezak 66 with a continuous weight of 175 kg) was used, and a blue solid image (cyan and magenta) 2 colors overlap) was output, the presence or absence of image omission in the recesses was observed, and the following rank evaluation was performed.
Rank 5; Good quality image with a uniform blue color across the entire paper Rank 4; Some parts of the paper have different colors Rank 3; Some parts of the paper have different colors Rank 2; Colors of recesses are different over the entire area of the paper Rank 1; Ranks up to rank 3 are allowed in the above rank where the recesses are white in the entire area of the paper.

(II) Observation of belt condition at the time of continuous image output of 10,000 sheets After outputting 10,000 consecutive images of the test chart, the test was stopped, the belt was taken out, and the appearance was observed.
The results are shown in Table 1.

  As described above, by adopting the configuration of the present invention, it is possible to realize an intermediate transfer belt for realizing an electrophotographic apparatus with high image quality and high durability capable of realizing a high transfer rate regardless of a transfer medium.

Japanese Patent No. 3248455 JP 2009-223282 A Japanese Patent Laid-Open No. 2001-100545

(Reference in FIG. 1)
11 base layer 12 resin layer 13 particles

(Reference in FIG. 2)
L Laser beam P Transfer paper 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photoconductor 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 Roller 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 in FIG. 3)
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 Driven roller 27 Lubricant coating device 50 Transfer conveyor belt 60 Secondary transfer bias roller 70 Static elimination roller

(Reference in FIG. 4)
41 Mold Drum 42 Belt 43 Applying Base Layer and Resin Layer Pressing Member 44 Particle 45 Powder Supply Device

Claims (4)

On at least a base layer, a rubber, or made of an elastomer, the surface in the intermediate transfer belt obtained by forming the elastic layer that have a concavo-convex shape due to the spherical nanoparticle, elastic layer contains an acrylic rubber and nitrile rubber,
The nitrile rubber and the acrylic rubber, a weight ratio, Ri 90 / 10-60 / 40 der,
The nitrile rubber is, the intermediate transfer belt, characterized in Rukoto that having a carboxyl group. The intermediate transfer belt according to claim 1 in which the toner image obtained a latent image formed on an image bearing member is developed with toner is characterized by and Turkey transferred.   The intermediate transfer belt according to claim 1, wherein the micro rubber hardness at 25 ° C. is 35 or less. 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. 4. An electrophotographic apparatus comprising a step of cleaning residual toner remaining on an intermediate transfer body, wherein the intermediate transfer body is the intermediate transfer belt according to claim 1. .

Images