JP5835648B2 - Transfer belt and image forming apparatus using the same - Google Patents

Description

  The present invention relates to an endless transfer belt that is stretched and rotated on a plurality of stretching members to transfer a toner image, and an image forming apparatus using the endless transfer belt.

  Conventionally, image forming apparatuses such as a color copying machine and a color printer are known as a so-called one-drum type and a tandem type. The one-drum type image forming apparatus includes a plurality of color developing devices around one photoconductor, and forms a composite toner image by attaching toner onto the photoconductor with these developing devices. The synthesized toner image is transferred to a transfer material to form a synthesized color image. The tandem type image forming apparatus includes a plurality of photoconductors arranged side by side, each having a developing device, and forms a single color toner image on each photoconductor. Then, these single color toner images are sequentially transferred onto a transfer material to form a composite color image. The tandem type image forming apparatus has an advantage that it is easy to increase the image forming speed as compared with the one-drum type.

  Color image forming apparatuses include a so-called direct transfer system and indirect transfer system. In the direct transfer method, images on the photosensitive member are sequentially transferred onto a transfer material conveyed by a transfer belt by a transfer device. In the indirect transfer method, images on each photoconductor are sequentially transferred to an intermediate transfer belt once at a primary transfer portion, and then images on the intermediate transfer belt are collectively transferred to a transfer material at a secondary transfer portion. The indirect transfer method can set the secondary transfer position relatively freely. In addition, even when there are fluctuations due to the environment of the transfer material to be conveyed, when transferring an image to the transfer material, the image on the intermediate transfer belt written by each photoconductor already matches and the image does not shift There is. Therefore, it has become mainstream to adopt an intermediate transfer system as a tandem system.

  Under these circumstances, the required characteristics (high-speed transfer, positional accuracy, etc.) of the intermediate transfer belt are stricter than before, and it is necessary to satisfy the characteristics corresponding to these requirements. ing. In particular, for positional accuracy, it is required to suppress fluctuation due to deformation such as elongation of the intermediate transfer belt itself due to continuous use. Further, the intermediate transfer belt is laid out over a wide area of the apparatus, and is required to be flame retardant because a high voltage is applied for transfer. In order to meet such requirements, polyimide resins, polyamideimide resins, and the like that are high elastic modulus and high heat resistance resins are mainly used as intermediate transfer belt materials.

  However, in an intermediate transfer belt having a high strength and a high surface hardness such as a polyimide resin, a high pressure is applied to the toner layer by a pressing force by a transfer member (transfer roller or the like) at a transfer portion where the toner image is transferred. For this reason, a so-called hollow image in which toner aggregates locally and a part of the image is not transferred may occur.

Further, in such an intermediate transfer belt, contact followability with a contact member (photosensitive member or transfer material) in the primary transfer portion or the secondary transfer portion is inferior. ) May occur and transfer unevenness may occur. In particular, in recent years, color image forming apparatuses often form images on various types of paper as transfer materials, and not only ordinary smooth paper but also high slip smoothness such as coated paper. Roughly surfaced materials such as recycled paper, embossed paper, 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.

Therefore, various intermediate transfer belts in which a relatively flexible elastic layer is laminated on a high hardness base layer have been proposed (see, for example, Patent Documents 1 and 2). In these intermediate transfer belts, by providing an elastic layer, belt deformation due to the pressing force of the transfer member at the transfer portion can be increased. Thereby, local concentration of the pressing force by the transfer member on the toner layer can be suppressed, toner aggregation can be suppressed, and the occurrence of a void image can be suppressed. In addition, since the intermediate transfer belt having the elastic layer has good adhesion to the paper as the transfer material in the transfer portion, high transfer performance can be realized regardless of the type and surface shape of the transfer material.

  On the intermediate transfer belt, a cleaning member that cleans residual toner on the intermediate transfer belt and a seal member that contacts both ends of the belt and prevents the toner from scattering during cleaning are installed. Since the elastic layer has a large frictional force and is inferior in mechanical characteristics and thermal characteristics, an intermediate transfer belt having an elastic layer is provided with a surface layer having a higher abrasion resistance than the elastic layer on the elastic layer. . However, in general, in the intermediate transfer belt, the base layer, the elastic layer, and the surface layer are formed with the same width, and the elastic layer is exposed on the side surface of the end portion. In such an intermediate transfer belt, although it can cope with the friction with the cleaning member, the elastic layer may be worn by the friction with the seal member. This is because the seal member is in contact with the belt end portion, but is installed with a margin so as to protrude from the end portion, so that it contacts not only the surface layer but also the side surface of the belt end portion. For this reason, there is a problem that the elastic layer exposed to the side surface of the end portion of the belt and the sealing member are rubbed and the elastic layer is worn. The shaved elastic material component comes into contact with the photosensitive member or the like to cause a blank image, or directly stains the transfer material. Further, the belt end portion is scraped, and the running of the belt becomes unstable, and the image is distorted.

  In Patent Document 1, an elastic layer and a surface layer having a hardness higher than that of the elastic layer are provided on the base layer, and both ends of the elastic layer are formed at both ends of the base layer in order to suppress breakage from the belt end during running of the belt. An intermediate transfer belt formed on the inner side than the portion has been proposed. In this transfer belt, both ends of the elastic layer are formed on the inner side than both ends of the base layer, similarly to the “transfer belt” in the means for solving the problems described later. However, the surface layer of the transfer belt does not have “spherical fine particles” as means for solving the problems described later. The surface layer of this transfer belt is a fluororesin film formed by dissolving and dispersing a fluororesin and a binder resin in a solvent, and applying and baking this, or a ceramic film formed by a plasma CVD method or the like. . Formation of such a surface layer requires a cost such as a solvent, and a technique for making the film thickness uniform is necessary.

  Patent Document 2 proposes a transfer belt in which a surface layer having a higher hardness than the base layer is formed on the base layer, and the end of the surface layer is formed on the inner side of the end of the base layer in order to suppress peeling of the surface layer. ing. However, in this transfer belt, since a flexible elastic layer is not formed, there is a possibility that a hollow image is generated as described above, or there is a problem in transferability to a transfer material having an uneven surface. There is.

  Patent Document 3 proposes an intermediate transfer belt in which a reinforcing layer is provided on the elastic layer at the end of the belt in order to suppress wear of the elastic layer due to the seal member. However, this transfer belt has a shape different from the “transfer belt” in the means for solving the problems described later, and an elastic layer is formed up to the belt end. Therefore, there is no problem when the seal member is rubbed only with the reinforcing layer, but when the seal member is rubbed with the elastic layer exposed on the side surface of the end portion of the belt, the elastic layer is also worn out. .

  The present invention has been made in view of the above problems. The purpose is to provide a transfer belt that can achieve high transfer performance regardless of the type and surface shape of the transfer material, and can provide wear resistance with a low cost and simple method, and an image forming apparatus using the transfer belt. It is to be.

In order to solve the above problems, the invention of claim 1 is a transfer belt on which a toner image is transferred while being stretched endlessly while being stretched by a plurality of stretch members, and at least an elastic layer composed of a base layer and an elastic member is laminated. And both ends of the elastic layer in the belt width direction parallel to the rotation axis of the tension member are both ends of the base layer. The elastic layer comprising: cleaning means for cleaning residual toner remaining on the transfer belt that is formed on the inner side of the transfer belt; and a toner scattering prevention member that contacts both ends of the transfer belt to prevent toner scattering. end of, an outer than the effective image area of the transfer belt, and is characterized in inner der Rukoto than the contact position of the toner scattering prevention member.

  The present invention provides a transfer belt capable of realizing high transfer performance regardless of the type and surface shape of a transfer material, and having wear resistance by a low cost and simple method, and an image forming apparatus using the transfer belt. There is an excellent effect of providing.

FIG. 2 is a configuration diagram showing a main configuration of a printer according to the present embodiment. FIG. 3 is a cross-sectional view illustrating a main configuration of an intermediate transfer belt mounted on the printer. FIG. 3 is an enlarged schematic view of the surface of the intermediate transfer belt observed from directly above. The perspective view of the base layer belt produced so that a film thickness might differ in the width direction. The block diagram explaining the formation method of a spherical fine particle layer. FIG. 3 is a cross-sectional view showing the shape of the intermediate transfer belt according to the first embodiment. FIG. 4 is a schematic diagram illustrating a positional relationship between a cleaning member and an intermediate transfer belt. FIG. 4 is a cross-sectional view illustrating a configuration of an intermediate transfer belt according to a second embodiment. FIG. 4 is a cross-sectional view illustrating a configuration of an intermediate transfer belt according to a third embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of an intermediate transfer belt according to a fourth embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of an intermediate transfer belt according to a fifth embodiment.

  Hereinafter, as an embodiment of an image forming apparatus to which the present invention is applied, a color printer adopting an intermediate transfer system in an electrophotographic 4-drum type will be described. First, the basic configuration of the printer will be described. FIG. 1 is a configuration diagram illustrating a main configuration of the printer. As shown in FIG. 1, this printer includes four image forming units 1Y, 1M, 1C for forming colored toner images of cyan (C), yellow (Y), magenta (M), and black (BK). , BK. In the following, the subscripts C, Y, M, and BK indicate cyan, yellow, magenta, and black, respectively. Each of the image forming units 1C, Y, M, and BK includes respective photoreceptors 2Y, M, C, and BK that carry toner images of respective colors and rotate in the direction of arrow A in the drawing. As each photoconductor 2 for each color, an OPC photoconductor is usually used. Around each of these photoreceptors 2Y, 2M, 2C, and 2BK, charging devices 3Y, 3M, 3C, and BK that uniformly charge the surface of each photoreceptor 2 and the surfaces of each photoreceptor 2 that are uniformly charged are provided. Exposure devices 4Y, 4M, 4B, and 4B that form an electrostatic latent image by exposing and scanning a laser beam based on image data, and developing devices 5Y, 5M, and 5B that develop the electrostatic latent image formed on the surface of each photoreceptor 2. C, BK, cleaning devices 6Y, M, C, BK for cleaning the surface of each photoconductor 2 after the transfer of the toner image, and a static elimination device (not shown) for removing residual charges on the surface of each photoconductor 2 after the cleaning are provided. . The developing devices 5Y, M, C, and BK use a two-component magnetic brush developing system. The image data is image information obtained by reading a document by an external scanner (not shown), image information sent from an external personal computer, and the like. Further, the image forming units 1Y, 1M, 1C, and 1B support the charging device 3, the developing device 5, and the cleaning device 6 disposed around the photosensitive member 2 as a single unit on a common support. Yes, it is detachable from the printer body.

  In addition, the printer includes an intermediate transfer unit 10 below the image forming unit 1 for transferring the toner image developed on the photoreceptors 2Y, 2M, 2C, and 2BK onto a sheet P as a transfer material. The intermediate transfer unit 10 includes an intermediate transfer belt 20 that is stretched by a plurality of stretching rollers 11, 12, and 13 including a driving roller and rotationally driven in the direction of arrow B in the figure. The intermediate transfer unit 10 sandwiches the intermediate transfer belt 20 between the photoreceptors 2Y, M, C, and BK and the primary transfer rollers 14Y, M, C, and BK to which a predetermined voltage is applied to form a primary transfer nip. . In addition, the intermediate transfer unit 10 forms a secondary transfer nip by sandwiching the intermediate transfer belt 20 between the secondary transfer backup roller 13 and the secondary transfer roller 15 to which a predetermined voltage is applied. The colored toner images on the photoreceptors 2Y, 2M, 2C, and 2BK developed by the image forming units 1Y, 1M, 1C, and 1BK are sequentially superimposed on the intermediate transfer belt 20 at the primary transfer nip and primarily transferred. The four-color superimposed color toner image transferred onto the intermediate transfer belt 20 is secondarily transferred onto the paper P at the secondary transfer nip.

  The printer includes a sheet feeding cassette, a registration roller pair 16, a transfer conveyance belt 17, a fixing device 18, and the like (not shown) below the intermediate transfer unit 10. The paper feed cassette is configured so as to be able to be taken in and out of the housing of the printer, and feeds the uppermost paper P to be stored one by one toward the registration roller pair 16. The registration roller pair 16 sandwiches the paper P supplied by the paper feed cassette between the rollers, and sends it to the secondary transfer nip at a timing that can be synchronized with the four-color superimposed color toner image on the intermediate transfer belt 20. The transfer conveyance belt 17 conveys the paper P, which has been secondarily transferred (collectively transferred) by the secondary transfer bias roller 15, toward the fixing device 18. The fixing device 18 sandwiches the paper P in a fixing nip formed by contact between a fixing roller containing a heat source such as a halogen lamp and a pressure roller pressed toward the fixing roller. To fix.

  In the printer having such a configuration, image formation is performed as follows. For example, in the cyan image forming unit 1C, the surface of the photoreceptor 2C uniformly charged by the charging device 3C is irradiated with the laser beam modulated and deflected by the exposure device 4C while being scanned to form an electrostatic latent image. It is formed. The electrostatic latent image on the photoreceptor 2C is developed by the developing device 5C to become a yellow toner image. The toner image on the photoreceptor 2C is transferred onto the paper P at the primary transfer nip that faces the primary transfer roller 14C with the intermediate transfer belt 20 interposed therebetween. The surface of the photoreceptor 2C after the toner image has been transferred is cleaned by the cleaning device 15C, and the surface is initialized by the static eliminator to prepare for the formation of the next electrostatic latent image.

  For the other image forming units 10Y, 10M, and BK, the above-described image forming process is executed in synchronization with the movement of the intermediate transfer belt 20, and a four-color superimposed toner image is formed on the intermediate transfer belt 20. On the other hand, the paper P fed from the paper feed cassette is sent at a predetermined timing by the registration roller pair 16 and conveyed to the secondary transfer nip. Then, the four-color superimposed toner images are collectively transferred onto the paper P at the secondary transfer nip. The paper P onto which the four-color superimposed toner images have been collectively transferred is transported by the transfer transport belt 17, subjected to fixing processing by the heating / pressurizing action of the fixing device 18, and discharged outside the apparatus.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt 20 is removed from the intermediate transfer belt 20 by the cleaning member 30. A lubricant application device 31 is disposed on the downstream side of the cleaning member 30. The lubricant application device 31 includes a solid lubricant and a conductive brush that rubs the intermediate transfer belt 20 to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt 20 and applies a solid lubricant to the intermediate transfer belt 20. The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt 20, preventing the occurrence of filming, and improving the durability.

  Next, the configuration of the intermediate transfer belt 20 that is a characteristic part of the printer according to the present embodiment will be described in detail. FIG. 2 is a cross-sectional view of a main part showing a main part configuration of the intermediate transfer belt according to the present embodiment. As shown in FIG. 2, the intermediate transfer belt 20 has a flexible elastic layer 22 laminated on a rigid base layer 21 that can be relatively bent. A spherical fine particle is formed on the outermost surface of the elastic layer 22. 23 are arranged (buried) independently in the surface direction, and the surface has a uniform uneven shape. The spherical fine particles 23 on the elastic layer 22 are hardly overlapped in the film thickness direction between the spherical fine particles, and the spherical fine particles are not completely buried in the elastic layer 22.

"Base layer"
First, the base layer 21 of the intermediate transfer belt 20 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 polyvinylidene fluoride (PVDF) or ethylene / tetrafluoroethylene copolymer (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 particularly preferable. As polyimide resin and polyamideimide resin, general-purpose products from manufacturers such as Toray DuPont, Ube Industries, Shin Nippon Rika, JSR, Unitika, IST, Hitachi Chemical, Toyobo, Arakawa Chemical, etc. are used and used. can do.

Examples of the electrical resistance adjusting material include metal oxide, carbon black, ionic conductive agent, and conductive polymer material. Examples of the metal oxide include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. Moreover, in order to improve dispersibility, the metal oxide may be subjected to surface treatment in advance. Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black. Examples of the ionic conductive agent include 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 intermediate transfer belt manufacturing method further includes additives such as a dispersion aid, a reinforcing material, a lubricant, a heat conduction material, and an antioxidant, as necessary, in the coating liquid containing at least the resin component. May be.

In the case of carbon black, the content of the electric resistance adjusting material is 10 to 25 wt%, preferably 15 to 20 wt% of the total solid content in the coating solution. Moreover, as content in the case of a metal oxide, it is 1-50 wt% of the total solid of a coating liquid, Preferably it is 10-30 wt%. When the content is less than the range of each of the electric resistance adjusting materials, it becomes difficult to obtain uniformity of the resistance value, and the fluctuation of the resistance value with respect to an arbitrary potential increases. On the other hand, when the content is larger than the above ranges, the mechanical strength of the intermediate transfer belt is lowered, which is not preferable in practical use.

The base layer 21 suitably equipped as the intermediate transfer belt 20 preferably has a surface resistance of 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ and a volume resistance of 1 × 10 ⁸ to 1 × 10 ¹¹ Ω. -The amount of electrical resistance adjusting material such as carbon black is included so as to be cm, but from the viewpoint of mechanical strength, a material that can be achieved with an addition amount that is not brittle and does not easily break is selected. That is, when the intermediate transfer belt 20 is used, an electrical property is obtained by using a coating liquid in which the blending of the resin component (for example, polyimide resin precursor or polyamideimide resin precursor) and the electrical resistance adjusting material is appropriately adjusted. It is preferable to manufacture and use an endless belt having a balance between (surface resistance and volume resistance) and mechanical strength.

There is no restriction | limiting in particular as thickness of the said base layer 21, Although it can select suitably according to the objective, 30 micrometers-150 micrometers are preferable, 40 micrometers-120 micrometers are more preferable, 50 micrometers-80 micrometers are especially preferable. If the thickness of the base layer 21 is less than 30 μm, the belt may be easily torn due to cracks, and if it exceeds 150 μm, the belt may be broken by bending. On the other hand, when the thickness of the base layer 21 is within the particularly preferable range, it is advantageous in terms of durability. Regarding the base layer 21, in order to improve running stability, it is preferable to eliminate film thickness unevenness as much as possible.

There is no restriction | limiting in particular as a method of adjusting the thickness of the said base layer 21, According to the objective, it can select suitably. For example, measurement with a contact type or eddy current type film thickness meter or a method of measuring a cross section of the film with a scanning electron microscope (SEM) can be mentioned.

"Elastic layer"
Next, the elastic layer 22 laminated on the base layer 21 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, ozone resistance, flexibility, adhesion to spherical fine particles 23, imparting flame retardancy, and environmental stability are provided. Acrylic rubber is most preferable from the surface. Hereinafter, the acrylic rubber will be described.

The acrylic rubber used for the elastic layer 22 may be commercially available and is not particularly limited. However, among the various crosslinking systems (epoxy groups, active chlorine groups, carboxyl groups) of acrylic rubber, the carboxyl group crosslinking system is excellent in rubber properties (especially compression set) and processability, so select the carboxyl group crosslinking system. It is preferable to do.

The crosslinking agent used for the carboxyl group-crosslinked acrylic rubber is preferably an amine compound, and most preferably a polyvalent amine compound. Specific examples of such amine compounds include aliphatic polyvalent amine crosslinking agents and aromatic polyvalent amine crosslinking agents. Examples of the aliphatic polyvalent amine cross-linking agent include hexamethylene diamine, hexamethylene diamine carbamate, N, N′-dicinnamylidene-1,6-hexane diamine, and the like. Aromatic polyvalent amine crosslinking agents include 4,4′-methylenedianiline, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4 ′-(m-phenylenediene. Isopropylidene) dianiline, 4,4 ′-(p-phenylenediisopropylidene) dianiline, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-diaminobenzanilide, 4, 4'-bis (4-aminophenoxy) biphenyl, m-xylylenediamine, p-xylylenediamine, 1,3,5-benzenetriamine, 1,3,5-benzenetriaminomethyl and the like can be mentioned. The blending amount of the crosslinking agent is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic rubber. When the blending amount of the crosslinking agent is too small, crosslinking is not sufficiently performed, so that it is difficult to maintain the shape of the crosslinked product. On the other hand, when there is too much content, a crosslinked material will become hard too much and the elasticity etc. as a crosslinked rubber will be impaired.

  Moreover, in the elastic layer 22 made of the acrylic rubber, a crosslinking accelerator may be further blended and used in combination with the crosslinking agent. The crosslinking accelerator is not limited, but is preferably a crosslinking accelerator that can be used in combination with the polyvalent amine crosslinking agent. Examples of such a crosslinking accelerator include guanidine compounds, imidazole compounds, quaternary onium salts, tertiary phosphine compounds, weak metal alkali metal salts, and the like. Examples of the guanidine compound include 1,3-diphenylguanidine, 1,3-diortolylguanidine and the like. Examples of the imidazole compound include 2-methylimidazole and 2-phenylimidazole. Examples of the quaternary onium salt include tetra n-butylammonium bromide and octadecyltri-n-butylammonium bromide. Examples of the polyvalent tertiary amine compound include triethylenediamine and 1,8-diaza-bicyclo [5.4.0] undecene-7 (DBU). Examples of the tertiary phosphine compound include triphenylphosphine and tri-p-tolylphosphine. Examples of the alkali metal salt of a weak acid include inorganic weak acid salts such as sodium or potassium phosphates and carbonates, and organic weak acid salts such as stearates and laurates.

  The amount of the crosslinking accelerator used is preferably 0.1 to 20 parts by weight, more preferably 0.3 to 10 parts by weight per 100 parts by weight of the acrylic rubber. When there are too many crosslinking accelerators, the crosslinking rate may become too fast at the time of crosslinking, the bloom of the crosslinking accelerator on the surface of the crosslinked product may occur, or the crosslinked product may become too hard. If the amount of the crosslinking accelerator is too small, the tensile strength of the crosslinked product may be remarkably reduced, or the elongation change or the tensile strength change after heat load may be too large.

  In preparing the acrylic rubber, an appropriate mixing method such as roll mixing, Banbury mixing, screw mixing, or solution mixing can be employed. The order of blending is not particularly limited, but after sufficiently mixing components that are not easily reacted or decomposed by heat, as a component that is easily reacted by heat or a component that is easily decomposed, for example, a crosslinking agent, etc. What is necessary is just to mix in a short time.

  Acrylic rubber can be made into a crosslinked product by heating. The heating temperature is preferably 130 to 220 ° C, more preferably 140 to 200 ° C, and the crosslinking time is preferably 30 seconds to 5 hours. As a heating method, a method used for crosslinking of rubber such as press heating, steam heating, oven heating, hot air heating and the like may be appropriately selected. Further, after cross-linking once, post-cross-linking may be performed in order to surely cross-link to the inside of the cross-linked product. Post-crosslinking is preferably performed for 1 to 48 hours, although it varies depending on the heating method, crosslinking temperature, shape, and the like. What is necessary is just to select the heating method and heating temperature at the time of post-crosslinking suitably.

The flexibility of the elastic layer 22 is preferably such that the micro rubber hardness value at 25 ° C. and 50% RH is 40 or less. The micro rubber hardness can be obtained by using a commercially available micro rubber hardness meter, for example, by using “Micro Rubber Hardness Meter MD-1” of Kobunshi Keiki Co., Ltd.

The thickness of the elastic layer 22 is preferably 400 μm to 1000 μm, more preferably 500 μm to 700 μm. If it is 400 μm or less, the image quality for paper types with surface irregularities will be insufficient. When the thickness is 1000 μm or more, the film becomes heavy, becomes easy to bend, the warpage becomes large and the running performance becomes unstable, or cracks occur due to bending at the roller curvature part for stretching the belt. Since it becomes easy, it is not preferable.

The length of the elastic layer 22 in the belt width direction is preferably set to 300 mm or more from the viewpoint of speeding up, high image quality, and high durability of recent electrophotography.

The elastic layer 22 appropriately contains a material such as a resistance adjuster for adjusting electrical characteristics and, if necessary, an antioxidant, a reinforcing agent, a filler, and a vulcanization accelerator in the selected material. Mix.

The resistivity control necessary for the intermediate transfer belt 20 requires the addition of a conductive agent because acrylic rubber alone has a high resistivity. For controlling the resistivity, it is possible to add carbon or an ionic conductive agent. However, in the present invention, the rubber hardness is important, so it is preferable to use an ionic conductive agent that is effective when added in a small amount and does not affect the rubber hardness. . Specifically, it is preferable to add 0.01 to 3 parts of various perchlorates and ionic liquids with respect to 100 parts of rubber. If the addition amount of the ionic conductive agent is 0.01 parts or less, the effect of reducing the resistivity cannot be obtained, and if the addition amount is 3 parts or more, the possibility that the conductive agent blooms or bleeds to the belt surface becomes high. The resistance value of the elastic layer 22 used for the intermediate transfer belt 20 is 1 × 10 ⁸ to 1 × 10 ¹³ Ω / □ in surface resistance and 1 × 10 ⁷ to 1 × 10 ¹² Ω · cm in volume resistance. It is preferable to adjust in this way.

"Spherical fine particles"
Next, the spherical fine particles 23 attached on the elastic layer 22 will be described. Here, the spherical fine particles are fine particles having a volume average particle diameter of 100 μm or less and a true spherical shape, insoluble in an organic solvent, and having a 3% thermal decomposition temperature of 200 ° C. or higher.

The material of the spherical fine particles 23 is not particularly limited, and examples thereof include spherical fine particles mainly composed of resins such as acrylic resin, melamine resin, polyamide resin, polyester resin, silicone resin, and fluorine resin. Further, the surface of particles made of these resin materials may be subjected to surface treatment with a different material. The spherical fine particles 23 referred to here also include spherical fine particles made of a rubber material. A structure in which the surface of spherical fine particles made of a rubber material is coated with a hard resin is also applicable. The spherical fine particles 23 may be hollow or porous spherical fine particles.

Such spherical fine particles 23 are more slippery and releasable than toner than the elastic layer. As a result, the abrasion resistance of the intermediate transfer belt 20 can be improved, and the toner can be prevented from being excessively adhered by improving the releasability, thereby improving the cleaning performance and the transfer performance.

As the spherical fine particles 23, silicone spherical fine particles are most preferable as those having high lubrication and releasability with respect to the toner and high wear 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 1.0 μm or less, the effect of transfer performance due to the particles cannot be sufficiently obtained. On the other hand, when the particle size is 5.0 μm or more, the surface roughness increases and the gap between the particles increases. There arises a problem that transfer cannot be performed or cleaning is poor. Furthermore, since many particles have high insulating properties, if the particle size is too large, a residual charging potential due to the particles causes a problem that image disturbance occurs due to accumulation of the potential during continuous image output.

There is no restriction | limiting in particular as said spherical fine particle 23, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the commercially available products include silicone particles (manufactured by Momentive Performance Materials, trade name “Tospearl 120”, trade name “Tospearl 145”, trade name “Tospearl 2000B”), acrylic particles (manufactured by Sekisui Plastics Co., Ltd., Trade name “Techpolymer MBX-SS”).

  Next, the surface state of the intermediate transfer belt 0 will be described in more detail. FIG. 3 shows an enlarged schematic view of the surface of the intermediate transfer belt observed from directly above. As shown in FIG. 3, the surface state of the intermediate transfer belt 20 takes a form in which spherical fine particles 23 having a uniform particle diameter are arranged in an orderly manner, and the overlapping of the spherical fine particles 23 is hardly observed. The diameter of the cross section of the spherical fine particles 23 constituting the surface is preferably uniform, and specifically, the distribution width is preferably ± (average particle size × 0.5) μm or less. In order to form this, it is preferable to use particles having a uniform particle size as much as possible, but the particle size distribution can be obtained by forming a surface by a method in which particles having a certain particle size can be selectively formed on the surface without using this. It is good also as a structure used as a width | variety. The surface area occupied by the spherical fine particles 23 is preferably 60% or more. If it is 60% or less, the exposed portion of the elastic layer 23 is too much, and the toner comes into contact with the elastic layer 23, and good transferability cannot be obtained.

In the present embodiment, the spherical fine particles 23 are partially embedded in the elastic layer 22, but the burying rate is preferably over 50% and less than 100%, preferably 51% to 90%. % Is more preferable. If it is 50% or less, the spherical fine particles 23 are likely to be detached during long-term use in the image forming apparatus, resulting in poor durability. On the other hand, 100% is not preferable because the effect of the spherical fine particles 23 on the transferability is reduced. The burying rate is a rate of burying in the elastic layer 22 having a diameter in the depth direction of the spherical fine particles 23. The burying rate referred to here is that all the spherical fine particles 23 exceed 50% and are 100%. It does not mean that the value is less than 50%, and it is sufficient that the numerical value expressed by the average burial rate when viewed from a certain visual field exceeds 50% and does not reach 100%. However, when the burying rate is 50%, almost no spherical fine particles 23 completely buried in the elastic layer 22 are observed in the cross-sectional observation by the electron microscope (the spherical fine particles 23 completely buried in the elastic layer 22). Number% is 5% or less of the whole particles). The method for measuring the burying rate of the spherical fine particles 23 in the intermediate transfer belt 20 is not particularly limited and may be appropriately selected according to the purpose. For example, the cross section of the intermediate transfer belt 20 is scanned with a scanning electron microscope (SEM). It is possible to measure by observing.

"Production method of intermediate transfer belt"
Next, an example of a method for producing the intermediate transfer belt 20 having the above configuration will be described. First, a method for producing the base layer 21 using a coating solution containing at least a resin component, that is, a coating solution containing the polyimide resin precursor or the polyamideimide resin precursor will be described. While slowly rotating a cylindrical mold, for example, a cylindrical metal mold, a coating liquid containing at least a resin component (for example, a coating liquid containing a polyimide resin precursor or a polyamideimide resin precursor) is used as a nozzle or Application and casting (formation of a coating film) is performed uniformly on the entire outer surface of the cylinder by a liquid supply device such as a dispenser. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and the rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is formed, the mold is transferred to a heating furnace (firing furnace) capable of high-temperature processing, and the temperature is raised stepwise, and finally high-temperature heat processing (firing is performed at about 250 ° C. to 450 ° C. And sufficiently imidizing or polyimidizing the polyimide resin precursor or the polyamideimide resin precursor. After sufficiently cooling, the elastic layer 22 is subsequently laminated.

The elastic layer 22 can be manufactured by coating and forming on the base layer 21 using a rubber paint in which rubber is dissolved in an organic solvent, and then drying and vulcanizing the solvent. As the coating molding method, as with the base layer 21, existing coating methods such as spiral coating, die coating, and roll coating can be applied, but the thickness of the elastic layer 22 is increased in order to improve uneven transferability. As the coating method for forming a thick film, die coating and spiral coating are excellent, and as described above, the thickness of the elastic layer 22 is easily changed in the width direction. Coating is excellent. Therefore, here, spiral coating will be described. First, while rotating the base layer 21 in the circumferential direction and continuously supplying rubber paint with a round or wide nozzle, the nozzle is moved in the width direction of the base layer 21 to spiral the paint on the base layer 21. Apply. The paint applied spirally on the base layer 21 is dried while being leveled by maintaining a predetermined rotation speed and drying temperature. Thereafter, it is formed by further vulcanization (crosslinking) at a predetermined vulcanization temperature. The vulcanized elastic layer 22 is then sufficiently cooled. The film thickness in the belt width direction can be changed by changing the discharge amount of the nozzle, the distance between the nozzle dies, or changing the rotational speed of the dies. FIG. 4 shows a perspective view of the endless belt manufactured as described above. As shown in FIG. 4, the elastic layer 22 can be formed on the base layer 21 such that the film thickness decreases from the elastic layer central portion 22 a to the elastic layer end rear side 22 b and the elastic layer front end.

The spherical fine particles 23 are adhered on the elastic layer 22 by heating and drying the elastic layer 22 in the above process, and then applying it before vulcanization, or applying it onto the cooled elastic layer 22 after vulcanization. It is possible. From the viewpoint of reliably suppressing the detachment of the spherical fine particles 23 from the elastic layer 22, it is more preferable to apply the spherical fine particles 23 before vulcanization of the elastic layer 22. FIG. 5 is a configuration diagram illustrating a method for forming a spherical fine particle layer. As a method for forming the spherical fine particle layer, for example, as shown in FIG. 5, a powder is formed around a cylindrical metal mold 101 on which an endless belt 102 in which a base layer 21 and an elastic layer 22 are laminated is manufactured. The body supply device 105 and the pressing member 103 are installed. Then, while rotating the mold 101, the spherical fine particles 104 are uniformly applied to the surface of the elastic layer 22 from the powder supply device 105, and the spherical fine particles 104 applied to the surface are pressed by the pressing member 103 at a constant pressure. Hit it. The pressing member 103 removes excess spherical fine particles while embedding the spherical fine particles 104 in the elastic layer 22. In the present embodiment, since monodispersed spherical fine particles are used in particular, it is possible to form a uniform single particle layer by a simple process such as the leveling process using the pressing member 103. In this way, after the spherical fine particles 104 are uniformly arranged on the surface, the spherical fine particles 104 can be hardened by heating at a predetermined temperature and a predetermined time while being rotated, and a part of the spherical fine particles can be embedded in the elastic layer 22. After sufficiently cooling, the base layer 21 is detached from the mold 101 to obtain the desired intermediate transfer belt 20.

In the above process, the adjustment of the burying rate of the spherical fine particles 23 in the elastic layer 22 can be easily achieved by, for example, adjusting the length of the pressing time or the pressing force of the pressing member 103. Although it depends on the viscosity of the casting coating liquid, the solid content, the amount of solvent used, the particle material, etc., as a guideline, the pressing force of the pressing member 103 is set at a viscosity of 100 to 100,000 mPa · s of the casting coating liquid. By setting it in the range of 1 mN / cm to 1000 mN / cm, the burying rate of 50% to 100% can be achieved relatively easily.

Further, the resistance of the intermediate transfer belt 20 thus manufactured is adjusted by changing the amounts of carbon black and ionic conductive agent. At this time, it should be noted that the resistance is easily changed depending on the size of the spherical fine particles 23 and the occupied area ratio. The resistance can be measured by using a commercially available measuring instrument, for example, by using Hiresta manufactured by Dia Instruments.

[Embodiment 1]
Next, the shape of the intermediate transfer belt 20 according to the first embodiment will be described. Here, the belt width direction means a direction parallel to the rotation axis of the stretching roller that stretches the intermediate transfer belt. FIG. 6 is a cross-sectional view showing the configuration of the shape of the intermediate transfer belt. FIG. 7 is a schematic diagram illustrating the positional relationship between the cleaning member and the intermediate transfer belt. As shown in FIG. 6, the intermediate transfer belt 20 is characterized in that both end portions of the elastic layer 22 are inward of both end portions of the base layer 21 in the belt width direction. Here, it is preferable that the widths of the front side end portion (right side in FIG. 6) 21a and the rear side (left side in FIG. 6) end portion 21b of the base layer 21 are aligned with each other from the viewpoint of running stability. If the widths of the front end portion 21a and the rear end portion 21b are not equal, the intermediate transfer belt 20 loses balance and travel becomes unstable, and image distortion occurs.

Further, as shown in FIG. 7, both end portions of the elastic layer 22 are arranged on the inner side in the belt width direction with respect to the end portion of the seal member 32 in contact with the base layer 21, and the belt width is larger than the effective image area. Arranged outside in the direction (may be the same width as the effective image area). Since the portion that comes into contact with the seal member 32 is the base layer 21 having high hardness and wear resistance, wear of the end portion of the intermediate transfer belt 20 can be suppressed. Moreover, the wear of the elastic layer 22 can be suppressed by separating the installation positions of the seal member 32 and the elastic layer 22. Note that if the width of the elastic layer 22 is made smaller than the width of the effective image area of the intermediate transfer belt 20, the toner is not transferred to the paper P and image omission occurs, which is not preferable.

[Embodiment 2]
Next, the intermediate transfer belt according to the second embodiment will be described. FIG. 8 is a cross-sectional view illustrating a configuration of the intermediate transfer belt according to the second embodiment. In the intermediate transfer belt 24 shown in FIG. 8, spherical fine particles 23 such as silicone spherical fine particles are also formed on the end side surfaces 22a and 22b of the elastic layer 22 so that the end side surfaces 22a and 22b of the elastic layer 22 are not exposed. It has been applied. If the elastic material component remains exposed on the end side surfaces 22a and 22b of the elastic layer 22, when the seal member 32 is rubbed, it is scraped from the end side surfaces 22a and 22b of the elastic layer 22 by the friction. I know that. Therefore, it is preferable that the end side surfaces 22a and 22b of the elastic layer 22 are covered with spherical fine particles 23 having higher wear resistance than the elastic layer. Thereby, compared with the case where the edge part side surfaces 22a and 22b of an elastic layer are exposed, abrasion of an elastic layer can be suppressed reliably.

[Embodiment 3]
Next, an intermediate transfer belt according to Embodiment 3 will be described. FIG. 9 is a cross-sectional view illustrating a configuration of the intermediate transfer belt according to the third embodiment. In the intermediate transfer belt 25 shown in FIG. 9, the surface of the elastic layer 22 is so formed that the thickness of the elastic layer 22 outside the effective image area gradually decreases toward the end and the elastic layer 22 is not exposed. A spherical fine particle 23 such as a silicone spherical fine particle is coated on the surface. Thus, by eliminating the corners of the elastic layer 22 from which the spherical fine particles 23 can be easily removed, it is possible to surely prevent the elastic material component from being exposed, and the spherical fine particles 23 can be easily applied to the entire surface, which is more preferable. The presence or absence of the spherical fine particles 23 on the elastic layer 22 can be confirmed by observing with a scanning microscope (SEM).

[Embodiment 4]
Next, the configuration of the intermediate transfer belt according to the fourth embodiment will be described. FIG. 10 is a cross-sectional view illustrating a configuration of the intermediate transfer belt according to the fourth embodiment. In the intermediate transfer belt 26 shown in FIG. 10, reinforcing layers 27 are provided on the base layers 21 at both ends where the elastic layer 22 is not formed. If the end portion of the intermediate transfer belt is only the base layer, local cracks may occur or the belt may be easily broken from the end portions. Therefore, in the intermediate transfer belt 26 shown in FIG. 10, it is preferable to provide a reinforcing layer 27 at the end so that breakage from the belt end can be suppressed. As a material for the reinforcing layer 27, a material excellent in heat resistance and wear resistance may be selected.

[Embodiment 5]
Next, the configuration of the intermediate transfer belt according to the fifth embodiment will be described. FIG. 11 is a cross-sectional view illustrating a configuration of an intermediate transfer belt according to the fifth embodiment. In the intermediate transfer belt 28 shown in FIG. 11, reinforcing layers 27 are provided on the base layers 21 at both ends where the elastic layer 22 is not formed. Here, the thickness of the reinforcing layer 27 provided on the base layer 21 at both ends is substantially equal to the thickness of the elastic layer 2. By equalizing the thicknesses of the reinforcing layer 27 and the elastic layer 22, it is possible to cover all the end side surfaces of the elastic layer 22 with the reinforcing layer 27, and to reliably prevent wear of the end side surfaces of the elastic layer 22. More preferable.

In addition, it is preferable to select an insulator for the reinforcing layer 27 provided on the surface of both end portions of the intermediate transfer belts 26 and 28 shown in FIGS. When a voltage is applied from the brush to remove toner in the cleaning member 30, if the resistance value of the reinforcing layer 27 is low, discharge is preferentially generated between the reinforcing layer 2 and the brush. When the discharge occurs, the voltage is not uniformly applied to the entire belt, and the toner is not sufficiently cleaned. If a material having a high resistance value is selected for the reinforcing layer 27, a preferential voltage can be applied to the elastic layer 22.

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. The film thickness (C) at the center of the belt is the average film thickness of ± 50 mm in the center in the width direction, and the film thicknesses at the ends (front side F, rear side R) are the average film thickness of 50 mm from both ends in the width direction. Was calculated respectively. The film thickness was measured with a contact-type film thickness meter.

[Example 1]
A base layer coating solution shown below was prepared, and an endless belt base layer was prepared using this coating solution.
"Preparation of coating solution for base layer"
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. The base layer coating solution A was prepared by preparing a dispersion of (manufactured) so that the carbon black content was 17% by weight of the polyamic acid solid content and stirring and mixing well.

"Production of polyimide base belt"
Next, a metal cylindrical support whose outer surface having an outer diameter of 500 mm and a length of 400 mm was roughened by blasting was used as a mold and attached to a roll coater. Subsequently, the base layer coating liquid A was poured into the pan, the paint was pumped up at a rotation speed of the application roller of 40 mm / sec, and the thickness of the paint on the application roller was controlled by setting the gap between the regulation roller and the application roller to 0.6 mm. Thereafter, the rotational speed of the cylindrical support is controlled to 35 mm / sec to be close to the application roller, and the coating on the application roller is uniformly transferred onto the cylindrical support with a gap of 0.4 mm from the application roller. While maintaining the rotation, it was put into a hot air circulating dryer, gradually heated to 110 ° C. and heated for 30 minutes, further heated to 200 ° C. for 30 minutes, and the rotation was stopped. Then, this was introduced into a heating furnace (firing furnace) capable of high temperature treatment, and the temperature was raised stepwise to 320 ° C., followed by heat treatment (firing) for 60 minutes. After sufficiently cooling, a polyimide base layer belt A having a film thickness of 60 μm was obtained.

"Masking of polyimide base belt"
A 2.0 cm masking tape was applied to both ends (F) and (R) in the width direction of the polyimide base belt A obtained earlier. The width of 2.0 cm is a width that does not contact the seal member and that does not enter the effective image area of the intermediate transfer belt.

"Production of elastic layer on polyimide base belt"
A rubber composition was prepared by blending and kneading the following components in the proportions shown below.
Acrylic rubber (Nippon ZEON Co., Ltd./NipolAR12) 100 parts by weight stearic acid (beaded stearic acid Tsubaki made by NOF Corporation) 1 part by weight red phosphorus (NOVA Excel 140F made by Rin Chemical Industry Co., Ltd.) Electric Works Co., Ltd. Heidilite H42M) 40 parts by weight cross-linking agent (DuPont Dow Elastomer Japan Diak.No1
(Hexamethylenediamine carbamate)) 0.6 parts by weight cross-linking accelerator (VULCOFAC ACT55 (70% 1,8-diazabicyclo (5,4,0) undecene-7 salt with dibasic acid, 30%, manufactured by Safe Alcan) Amorphous silica)) 0.6 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%. Then, the cylindrical support having the polyimide base layer with the masking tape attached is rotated, and the rubber solution prepared earlier is moved to the cylindrical support axial method while being continuously discharged from the nozzle, and applied in a spiral manner. did. The coating amount was such that the final film thickness at the center was 550 μm. Thereafter, the cylindrical support coated with the rubber solution was put into a hot air circulating dryer while rotating as it was, heated to 100 ° C. at a heating rate of 4 ° C./min, and heated for 120 minutes.

Thereafter, the surface is taken out from the dryer and cooled, and on this surface, using the apparatus of FIG. 5, as spherical fine particles 23, silicone spherical fine particles (Tospearl 120 (volume average particle size 2.0 μm product); Momentive Performance Materials) ) Evenly on the surface. The pressing member of the polyurethane rubber blade was fixed to the elastic layer by pressing with a pressing force of 100 mN / cm. Subsequently, it was again put into a hot air circulating dryer, heated to 170 ° C. at a heating rate of 4 ° C./min, and heat-treated for 60 minutes.

Finally, the masking tape was peeled off to obtain an intermediate transfer belt A as shown in FIG. At this time, the thickness (C) of the central part was 610 μm, the widths (F) and (R) consisting only of the base layer part at the belt end part were both 2.0 cm, and the burial rate of the particles was 60%.

[Example 2]
The same procedure as in Example 1 was performed except that the masking tape width was changed from 2.0 cm to 5.0 cm in “masking of polyimide base layer belt surface” in Example 1. As a result, the widths (F) and (R) consisting only of the base layer portion at the belt end portion are both 5.0 cm from the end portion to the effective image area, and the elastic layer and the effective image area are substantially the same width. An intermediate transfer belt B was obtained.

[Example 3]
The same procedure as in Example 1 was performed except that the masking tape width was changed from 2.0 cm to 0.5 cm in “masking of polyimide base layer belt surface” in Example 1. As a result, the width (F) and (R) consisting only of the base layer at the belt end became 0.5 cm, and an intermediate transfer belt C in which the side surface of the elastic layer was in contact with the sealing member was obtained.

[Example 4]
Without applying a masking tape to the polyimide base layer belt A, the rubber solution was continuously ejected as it was and moved to the cylindrical support shaft method for coating in a spiral shape. Moreover, the coating was started from the inner side of 2.0 cm from the width of the base layer and stopped at the inner side of 2.0 cm, thereby providing 2.0 cm non-coating portions at both ends. By changing the discharge amount of the rubber paint in the middle, the thickness of the elastic layer was gradually changed from the non-image area toward the end of the elastic layer. The coating amount was such that the final film thickness at the center was 550 μm. Thereafter, the cylindrical support coated with the rubber paint was put into a hot air circulating dryer while rotating as it was, heated to 100 ° C. at a heating rate of 4 ° C./min, and heated for 120 minutes.

Thereafter, the product is taken out from the dryer and cooled, and on this surface, using the powder supply device 105 and the pressing member 103 shown in FIG. 0.0 μm product); Momentive Performance Materials) were evenly applied to the surface. The pressing member 103 of the polyurethane rubber blade was pressed with a pressing force of 100 mN / cm and fixed to the elastic layer. Subsequently, it was again put into a hot air circulating dryer, heated to 170 ° C. at a heating rate of 4 ° C./min, and heat-treated for 60 minutes. As a result of this step, as shown in FIG. 9, the width (F) and (R) of the belt end portions are both 2.0 cm, and the intermediate transfer belt D in which the film thickness of the elastic layer in the non-image area is gradually reduced is obtained. Obtained.

[Example 5]
After the masking tape was peeled off in the production procedure of Example 1, the same spherical fine particles 23 as in Example 1 were applied. By this process, as shown in FIG. 8, an intermediate transfer belt E in which the side surface of the elastic layer end portion was covered with particles was obtained.

[Example 6]
After the production of the belt of Example 1, the entire base layer was covered with a 200 μm thick reinforcing layer (Nitoflon (semiconductive adhesive tape, surface resistance value 102 to 104Ω). By this process, as shown in FIG. An intermediate transfer belt F having both end film thicknesses (F) and (R) of 260 μm was obtained.

[Example 7]
After the production of the belt of Example 1, the entire base layer was covered with a 550 μm thick reinforcing layer (Nitoflon (semi-conductive adhesive tape, surface resistance value 102 to 104Ω). By this process, as shown in FIG. An intermediate transfer belt G having both end film thicknesses (F) and (R) of 610 μm was obtained.

[Example 8]
After the production of the belt of Example 1, the entire base layer was covered with an insulating tape having a film thickness of 550 μm (double-sided Kapton insulating tape). Through this process, as shown in FIG. 11, the film thicknesses (F) and (R) at the belt end portions were both 610 μm, and an intermediate transfer belt H in which the reinforcing layer was an insulator was obtained.

[Comparative Example 1]
The thickness (F), (C), and (R) were 610 μm, respectively, in the same manner as in Example 1 except that the rubber coating material was directly discharged to the base layer without using a masking tape when the elastic layer of Example 1 was prepared. Become. An intermediate transfer belt I having elastic layers on both ends was obtained.

[Comparative Example 2]
In the same manner as in Example 1 except that the film thickness was changed by changing the discharge amount of the nozzle without using a masking tape at the time of producing the elastic layer of Example 1, the central thickness (C) was 610 μm, An intermediate transfer belt J was obtained in which elastic layers were provided at both ends where the end thicknesses (F) and (C) were 260 μm.

The intermediate transfer belts A to H of Examples 1 to 8 and Comparative Examples 1 and 2 were mounted on the image forming apparatus described with reference to FIG. 1 and evaluated as follows. The results are shown in Table 1.

  The belt wearing state after 200,000 continuous sheets was confirmed by visual rank determination. Judgment is that ◎ indicates no wear, ○ indicates that there is wear but is a practical level, and × indicates that wear is intense.

  In order to examine white spots due to the worn elastic material, the image quality (full-tone halftone with black toner) on plain paper (TYPE 6200) after continuous 200,000 sheet passing was determined visually. In the judgment, ◎ indicates no white space, ○ indicates white space, but it is usable level, and × is unusable.

  In order to investigate the influence of poor running due to belt wear, image distortion was confirmed. The image quality (full-tone halftone with black toner) on plain paper (TYPE 6200) after continuous 200,000 sheet passing was judged visually. In the judgment, ◎ indicates no distortion, ○ indicates some distortion, but the actual usable level, and x indicates unusable.

  From the results of Table 1, in Examples 1 to 3 in which the belt end portion is composed only of the base layer, the elastic layer is less likely to be worn compared to Comparative Examples 1 and 2 in which the elastic layer is formed up to the belt end portion. It can be seen that distortion and poor cleaning can be suppressed, and a high-quality image can be obtained. However, in Example 3, the frequency with which the end side surface of the elastic layer contacts the seal member is higher than that in Example 1. Therefore, the evaluation in Table 1 of Example 3 is the same as the evaluation of Example 1, but the side surface of the elastic layer end of the intermediate transfer belt C of Example 3 is the intermediate transfer belt A of Example 1-2. The amount of wear is larger than the side surface of the elastic layer end of B. On the other hand, in Examples 4 and 5 in which the elastic layer has spherical fine particles on the side surface of the elastic layer and the elastic layer is not exposed at all, wear of the elastic layer is surely suppressed. It turns out that it can suppress reliably. Further, in Examples 6 to 8 having the reinforcing layer at the belt end, as compared with the case where the belt end consists of only the base layer, the distortion of the belt is surely suppressed, and cracks and breaks from the belt end are suppressed. Can do. In particular, in Examples 7 and 8, in which the reinforcing layer and the elastic layer have the same thickness and the elastic layer is not exposed at all, the wear of the elastic layer is more reliably suppressed, so that the occurrence of white spots is more reliably prevented. It turns out that it can suppress. Further, in Example 8 in which the reinforcing layer is an insulator, it is possible to preferentially apply a voltage to the elastic layer and maintain good cleaning properties.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
In the transfer belt such as the intermediate transfer belt 20 to which the toner image is transferred while being endlessly moved while being stretched by a plurality of stretching members such as the stretching rollers 11, 12, and 13, at least the base layer such as the base layer 21 and the elastic layer A belt width direction in which an elastic layer such as an elastic layer 22 made of a member is laminated, has spherical fine particles 23 so that the surface of the elastic layer has a uniform uneven shape, and is parallel to the rotation axis of the tension member The both end portions of the elastic layer are formed inside the both end portions of the base layer. According to this, as described in the first embodiment, high transfer performance can be realized by the elastic layer formed in the effective image area regardless of the type and surface shape of the transfer material. Further, even if there is a toner scattering prevention member such as a seal member 32 that contacts both ends of the transfer belt to prevent toner scattering, the toner scattering prevention member and the elastic layer can be separated in the belt width direction. It is possible to prevent the elastic layer from being worn by rubbing against the toner scattering preventing member. The base layer having a higher hardness than the elastic layer is less likely to be worn by rubbing against the toner scattering preventing member. In addition, the transfer belt having spherical fine particles on the outermost surface is superior in transferability, cleaning properties, and abrasion resistance as compared with the case where the elastic layer is the outermost surface because the spherical fine particles have better lubricity than the elastic layer. . And since this spherical fine particle can be formed only by apply | coating a spherical fine particle independently without adjustment of a solvent or a film thickness, compared with the case where the surface layer as proposed in patent document 1 is formed. In addition, the cleaning member and the seal member can be provided with wear resistance by a low cost and simple method.
(Aspect B)
In the aspect A, the toner scattering prevention member such as the cleaning member 30 for cleaning the transfer residual toner remaining on the transfer belt and the seal member 32 for preventing the toner scattering by contacting both ends of the transfer belt. The end of the elastic layer is outside the effective image area of the transfer belt and inside the contact position of the toner scattering prevention member. According to this, as described in the first exemplary embodiment, since the elastic layer and the toner scattering preventing member can be separated from each other, it is possible to prevent the elastic layer from being worn by rubbing with the toner scattering preventing member. Therefore, it is possible to suppress the occurrence of whiteout images and image distortion due to wear of the elastic layer.
(Aspect C)
In aspect C, the side surface in the width direction of the elastic layer is covered with spherical fine particles. According to this, as described in the second embodiment, even if the toner scattering prevention member and the elastic layer may come into contact with each other, the elastic layer is not exposed, so that the abrasion of the elastic layer is reliably suppressed. can do.
(Aspect D)
In the transfer belt of the mode B or the mode C, the film thickness of the elastic layer outside the effective image area of the transfer belt is gradually decreased toward the end. According to this, as described in the third embodiment, there is no angle at which spherical fine particles can be easily removed, and it is easy to form a spherical fine particle layer on the entire surface of the elastic layer, and wear of the elastic layer can be more reliably suppressed.
(Aspect E)
In the transfer belt of the aspect A, B, C, or D, the transfer belt has a reinforcing layer such as the reinforcing layer 27 on the surface of the base layer at both ends of the transfer belt. According to this, as described in the fourth embodiment, since the reinforcing layers are provided at both ends, it is possible to suppress the occurrence of local cracks and the breakage of the belt.
(Aspect F)
In the transfer belt of aspect E, the thickness of the reinforcing layer is substantially the same as the thickness of the elastic layer. According to this, as described in the fifth embodiment, since the end surface of the elastic layer is covered with the reinforcing layer and the elastic layer is not exposed at all, the wear of the elastic layer can be more reliably suppressed.
(Aspect G)
In the transfer belt of aspect E or F, the reinforcing layer is made of an insulator. According to this, as described in the fourth and fifth embodiments, the voltage by the cleaning member can be preferentially applied to the elastic layer, and the cleaning property is excellent.
(Aspect H)
An image carrier such as a photoreceptor 2 on which a latent image is formed and capable of carrying a toner image, a developing unit such as a developing device 5 that develops the latent image formed on the image carrier with toner, and developed by the developing unit. A transfer belt such as an intermediate transfer belt 20 to which the transferred toner image is primarily transferred; a secondary transfer means for secondary transfer of the toner image carried on the transfer belt onto a recording medium such as paper P; and a transfer residue on the transfer belt. In an image forming apparatus including a cleaning unit such as a cleaning member 30 for cleaning toner and a toner scattering prevention member such as a seal member 32 that contacts both ends of the transfer belt to prevent toner scattering, the transfer belt may include the aspect A A G to G intermediate transfer belt is used. According to this, since the transfer belt is excellent in transferability and durability as described above, a high-quality image can be obtained over a long period of time.
(Aspect I)
The image forming apparatus according to aspect H is characterized in that a plurality of image carriers such as photoreceptors 2Y, 2M, 2C, and 2B that carry toner images of different colors are arranged in series. According to this, as described above, it is possible to increase the speed of image formation as compared with the case where a single image carrier is used.

  In this embodiment, a plurality of image forming units 1 including the photoconductors 2 are arranged side by side, toner images of different colors are formed on the photoconductors 2 of the respective image forming units 1, and the toner on each photoconductor is formed. Although the tandem color image forming apparatus that transfers an image superimposed on the intermediate transfer belt 20 has been described, the present invention is not limited to this. For example, the present invention may be employed in a one-drum type color image forming apparatus in which toner images of each color are sequentially formed on a single photoconductor, and each color toner image on the photoconductor is sequentially superimposed and transferred onto an intermediate transfer belt. .

20, 24, 25, 26, 28 Intermediate transfer belt 21 Base layer 22 Elastic layer 23 Spherical fine particle layer 27 Reinforcing layer 32 Seal member

JP 2009-48032 A JP 2011-28090 A JP 2009-300490 A

Claims (8)

In the transfer belt to which the toner image is transferred while being endlessly moved while being stretched by a plurality of stretch members,
At least an elastic layer composed of a base layer and an elastic member is laminated, and the surface of the elastic layer has a spherical fine particle so as to have a uniform uneven shape,
Both ends of the elastic layer in the belt width direction parallel to the rotation axis of the stretching member are formed on the inner side than both ends of the base layer ,
Cleaning means for cleaning the transfer residual toner remaining on the transfer belt, and a toner scattering prevention member that contacts the both ends of the transfer belt to prevent toner scattering,
An end portion of the elastic layer is outside the effective image area of the transfer belt and inside the contact position of the toner scattering preventing member . In the transfer belt of 請 Motomeko 1,
A transfer belt, wherein the side surface in the width direction of the elastic layer is covered with spherical fine particles. The transfer belt according to claim 1 or 2 ,
The transfer belt according to claim 1, wherein the thickness of the elastic layer outside the effective image area of the transfer belt is gradually reduced toward the end portion. The transfer belt according to claim 1, 2 or 3 ,
A transfer belt comprising reinforcing layers on the surface of a base layer at both ends of the transfer belt. The transfer belt according to claim 4 .
The transfer belt, wherein the thickness of the reinforcing layer is substantially equal to the thickness of the elastic layer. The transfer belt according to claim 4 or 5 ,
The transfer belt, wherein the reinforcing layer is made of an insulator. An image carrier on which a latent image is formed and capable of carrying a toner image, a developing unit that develops the latent image formed on the image carrier with toner, and a toner image developed by the developing unit are primarily transferred. A transfer belt, a secondary transfer unit for secondary transfer of a toner image carried on the transfer belt to a recording medium, a cleaning unit for cleaning residual toner on the transfer belt, and both ends of the transfer belt In an image forming apparatus comprising a toner scattering prevention member for preventing toner scattering,
Image forming apparatus, which comprises using a transfer belt according to claim 1 to 6 as the transfer belt. The image forming apparatus according to claim 7 .
An image forming apparatus, wherein a plurality of image carriers that carry toner images of different colors are arranged in series.

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