JP2003295627A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regularly prevent transfer failure caused by waving of an intermediate transfer belt or failure in drive of the belt, in an image forming apparatus using the elastic intermediate transfer belt having a difference in circumferential length between widthwise ends thereof. <P>SOLUTION: Seamless reinforcement members 91 are disposed on the backs of both the ends of the intermediate transfer belt 10. Each seamless reinforcement member is the one having a periphery which is the same in circumferential length as the internal face of the intermediate transfer belt and having no seams. Because there is a difference in circumferential length between the widthwise ends of the intermediate transfer belt, the circumferential lengths of the seamless reinforce members are different from each other. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile and a printer.
More specifically, the present invention relates to an image forming apparatus that primarily transfers an image formed on an image carrier onto an intermediate transfer belt, and secondarily transfers the primary transfer image on the intermediate transfer belt onto a transfer material.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus using an intermediate transfer belt has one or a plurality of image carriers, and a plurality of different toner images formed on the image carriers are formed on the intermediate transfer belt. It is known that primary transfer is sequentially performed and then secondary transfer is performed on a transfer material. The secondary transfer is to transfer the superimposed toner image formed on the intermediate transfer belt onto the transfer material at once. Among these, as one having one image carrier, for example, there is a one-drum type image forming apparatus having one image carrier and one optical system. Further, as a device having a plurality of image carriers, for example, there is a tandem type image forming apparatus in which a plurality of image carriers are arranged in parallel and each image carrier is provided with an individual image forming means.

An endless, elastic belt is used as the intermediate transfer belt of the above-mentioned intermediate transfer type image forming apparatus, and a belt manufacturing method using a mold as shown below is known as a manufacturing method thereof. Has been. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which the material is sprayed onto the cylindrical mold to form a thin film on the surface layer, and a cylindrical mold is used to form a solution of the material. There is a dip coating method in which the product is dipped in and pulled up. Furthermore, there are a casting method in which a material is injected between an inner die and an outer die, and a method in which a compound is wound around a cylindrical die and vulcanized and polished. Further, the belt is not limited to any one of these methods, and the belt can be manufactured by combining a plurality of manufacturing methods. An intermediate transfer belt having elasticity has been manufactured by these belt manufacturing methods.

By the way, in the above-described method of manufacturing a belt using a mold, in order to improve the releasability when the finished belt is removed from the mold, in order to improve the releasability of the belt, one end is added to the circumferential length of both ends in the belt width direction. A circumferential length difference is provided at both ends of the mold so that there is a difference with the other end. As the peripheral length difference, a mold having a peripheral length difference of about 0.05 to 0.31 [mm] is generally used. If the peripheral length difference exceeds 0.31 [mm], transfer unevenness occurs when the toner image is transferred from the photoconductor. Further, if the peripheral length difference is less than 0.05 [mm], it becomes difficult to release from the mold. If a large amount of a release agent is used to improve the releasability, the surface condition becomes unfavorable, such as belt slip due to the release agent adhering to the back surface of the intermediate transfer belt and deterioration of the back surface. A perimeter difference of more than [mm] is necessary.

[0005]

However, the circumferential length difference is provided at both ends of the mold as described above, and the circumferential length difference is generated between the both ends in the width direction of the elastic belt itself. For this reason,
When the intermediate transfer belt is stretched over a plurality of rollers and driven, the intermediate transfer belt may sometimes be wavy. This is because the driving speeds of the rollers are equal between the both ends of the belt, and as the driving progresses, the end on the side of the longer belt circumference is gradually left, and that portion is wavy due to the elasticity of the belt. When such waviness occurs on the intermediate transfer belt in the image forming apparatus, the primary transfer image or
This causes a defect that the transfer failure occurs in the next transfer image.

It is considered that the structure in which the tape is provided on the belt as described below is also effective in preventing the corrugation of the belt. For example, Japanese Patent Application Laid-Open No. 2000-1237 (Mitsubishi Chemical: division of Japanese Patent Application No. 3-105558) proposes that a reinforcing tape is adhered to both ends in the width direction inside the seamless belt base material. By adhering such a reinforcing tape to the seamless belt, it is considered effective not only to prevent meandering at the time of driving the belt but also to prevent corrugation. In addition, in JP-A-2000-289823 (Mitsubishi Chemical), the following is proposed. That is, a meandering prevention guide provided with a reinforcing base material, an adhesive layer applied to both surfaces of the reinforcing base material, and a guide base material adhered to one adhesive layer was provided at both ends in the width direction of the endless belt. It is a thing. It is considered that the seamless belt with the meandering prevention guide is also effective in preventing waviness when the belt is driven.

However, in the proposal of the above-mentioned Japanese Patent Application Laid-Open No. 2000-1237, a gap or a superposition occurs at the bonding portion between the end portions of the reinforcing tape, and this portion becomes a source of generation of minute vibration when the belt is driven. Will result in a banding image. In addition, the reinforcing tape may peel off from the bonded portion. Further, the above-mentioned JP-A-2000-289
In the proposal of Japanese Patent No. 823, the meandering prevention guide may be provided at both ends of the belt over the entire circumference of the belt or may be interrupted in the circumferential direction. However, when the meandering prevention guide is provided so as to be interrupted in the circumferential direction, a slight step is generated in the circumferential direction, and there is a risk that the belt is peeled off by driving the belt. Further, even when it is provided on the entire circumference of the belt, since the sheet-shaped guide is attached to the belt, a slight step or a discontinuous surface portion is generated in the end-attached portion, and the belt may be peeled off by driving the belt. The fact that the reinforcing tape, the meandering prevention guide, and the peeling-off may be caused by the driving of the intermediate transfer belt as described above means that the meandering prevention effect cannot be maintained. From the above, it is desired to constantly prevent the intermediate transfer belt from waviness and drive failure.

The present invention has been made in view of the above background, and its object is to show the following.
That is, in an image forming apparatus using an elastic intermediate transfer belt having a circumferential length difference between both ends in the width direction, it is possible to constantly prevent transfer failure caused by waviness of the intermediate transfer belt or drive failure.

[0009]

In order to achieve the above object, an image forming apparatus according to a first aspect of the present invention is an image forming apparatus for carrying a latent image on its surface, and a developing apparatus for developing the latent image on the image carrying body. Means, primary transfer means for primarily transferring the image formed on the image carrier onto an intermediate transfer body, and secondary transfer for secondary transfer of the primary transfer image on the intermediate transfer body onto a transfer material. And a reinforcement for reinforcing the intermediate transfer belt to the inner peripheral surface of the intermediate transfer belt in an image forming apparatus using an intermediate transfer belt that is an endless belt having elasticity as the intermediate transfer member. A member is provided, and an endless seamless seamless reinforcing member is used as the reinforcing portion. An image forming apparatus according to a second aspect is the image forming apparatus according to the first aspect, wherein the seamless reinforcing members are provided at both widthwise end portions of the inner peripheral surface of the intermediate transfer belt, and the seamless reinforcing member is made of a metal. It is characterized in that it has an elongation of 0.02 [%] or less at a tension of 1.96 [N / cm] and a thickness of 100 [μm] or less. The image forming apparatus according to claim 3 is the image forming apparatus according to claim 1.
Alternatively, in the image forming apparatus of No. 2, the inner peripheral surface of the intermediate transfer belt in the state where the seamless reinforcing member is provided is flat. Heretofore, various inventions have been proposed in order to prevent deviation of the belt that occurs when the belt is stretched over a plurality of rollers and driven. For example, Japanese Utility Model Laid-Open No. 5-12819 (Bandoh Kagaku Co., Ltd.) proposes a belt drive device that automatically detects a belt deviation (deviation) and performs a deviation correction operation based on the detection result. There is. In this publication, the belt deviation correction operation is performed without changing the tension applied to the belt, and the correction operation can be performed while preventing the belt from being damaged. However, this actual Kaihei 5-
In No. 12819, a new device configuration is required for detecting the deviation of the belt and correcting the deviation, which complicates the entire belt driving device and incurs a cost therefor. Further, in the above-mentioned Japanese Patent Laid-Open No. 2000-1237, a meandering preventing member is provided on the reinforcing tape.
As a result, meandering can be prevented when the belt is driven. Further, the above-mentioned JP-A-2000-28
In Japanese Patent Publication No. 9823, the meandering prevention guide provided with the above-described guide base material can prevent the meandering during belt driving. However, JP-A-2000-1237 and JP-A-2000-28
According to the configuration of Japanese Patent No. 9823, as described above,
The reinforcing tape or the meandering prevention guide may be peeled off by driving the belt. Therefore, the effect of preventing the deviation cannot be maintained. Therefore, the image forming apparatus according to claim 4 is the image forming apparatus according to claim 1,
In the second or third image forming apparatus, the seamless reinforcing member is provided with a detent member for preventing the belt from deviating when the intermediate transfer belt is driven. According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the rubber hardness of the anti-shift member is
It is characterized by being 50 or more and 90 or less.
According to a sixth aspect of the present invention, in the image forming apparatus according to the first, second, third, fourth or fifth aspect, the developing means is capable of developing a plurality of latent images of different colors with toner, The transfer unit is configured to be capable of forming a superposed toner image on the intermediate transfer belt by sequentially primary-transferring a plurality of toner images of different colors formed by the developing unit onto the intermediate transfer belt. It is characterized by.
In the image forming apparatus according to the first to sixth aspects, the reinforcing member provided on the inner peripheral surface of the intermediate transfer belt is formed in an endless and seamless shape. This seamless reinforcing member is provided on the inner peripheral surface of the intermediate transfer belt to reinforce the intermediate transfer belt. As a result, even if the intermediate transfer belt is driven repeatedly, the seamless reinforcing member is seamless and seamless, and therefore does not separate from the seams or discontinuous portions. Therefore, even if the intermediate transfer belt has a difference in circumferential length at both ends in the belt width direction and is elastic, it is possible to almost constantly prevent the elastic belt from stretching and waviness when the belt is driven. Further, by preventing the intermediate transfer belt from waving, it is possible to prevent the driving failure of the intermediate transfer belt due to the waving.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to an electrophotographic printer (hereinafter referred to as a printer) which is an image forming apparatus will be described below.

First, a schematic structure of this printer will be described. FIG. 2 is a schematic configuration diagram showing a cross section of the printer of this embodiment. In FIG. 2, a flexible photoconductor belt (hereinafter, referred to as a photoconductor belt) 1 as a latent image carrier is stretched between rotating rollers 2 and 3 and is rotated by the rotating roller 2 so that an arrow mark It is conveyed in the A direction (clockwise direction).
Below the photoconductor belt 1, a charging charger 4 for uniformly charging the surface of the photoconductor belt 1 and a laser writing system unit 5 for exposing the surface to carry an electrostatic latent image ( Hereinafter, a writing unit) is provided. Writing unit 5 has a resolution of 600D
Laser light image exposure of PI or more is performed. On the left side of the photosensitive belt 1 in the figure, yellow, cyan, magenta,
A revolver developing device 6 is provided as a rotary developing device that holds four developing devices that respectively use black developer around a rotation axis. Further, on the right side of the photosensitive belt 1 in the figure, an intermediate transfer belt 10 for intermediately transferring an image in the image forming process is provided with a rotating roller 11,
It is stretched between twelve. Then, the intermediate transfer belt 10 is conveyed in the direction of arrow B (counterclockwise direction) in the drawing by the rotational driving of the rotating roller 11.

The photosensitive belt 1 and the intermediate transfer belt 10 are pressed by the rotating roller 3 to form a contact portion. A bias roller 13 having conductivity is disposed on the side of the intermediate transfer belt 10 at this contact portion, and a transfer bias is applied while contacting the back surface of the intermediate transfer belt 10 under predetermined conditions.

The tension applied to the intermediate transfer belt 10 is preferably 0.2 to 1.5 [N / cm]. 0.2 [N / cm]
If it is less than 1, slip is likely to occur, and 1.5 [N / c
If it exceeds m], when the intermediate transfer belt 10 is repeatedly used, minute cracks on the belt surface and edge breakage may occur. Unlike the contact type charging roller, the charging charger does not come into contact with the surface of the photosensitive belt 1 to cause scratches, which is particularly advantageous in a color image forming apparatus.

Further, in this embodiment, the intermediate transfer belt 10 is driven at a high process speed of 100 [mm / s] or more. In the color image forming apparatus shown in FIG. 2, yellow, cyan, magenta, and black toner images are formed on the photosensitive belt 1 and then yellow, cyan, magenta, and black toner images are sequentially superimposed on the intermediate transfer belt 10 to form a color image. And Therefore, unless the process speed is set to a high speed as compared with a single-color image forming apparatus, the speed of printing on the transfer paper will be reduced. Further, the peripheral length of the intermediate transfer belt 10 is preferably 420 [mm] or more for the length of an A3 vertical image, and 450 [mm] or more from the printing speed.

The photoconductor belt 1, the intermediate transfer belt, the rollers 2, 3, 11, and 12 described above, and the rollers 14, 19, and 20 described later are arranged in the process cartridge 31. Then, this process cartridge 31
Is detachably attached to the printer body. This facilitates removal and installation of the unit from the printer body, improving the maintainability.

Further, the main body structure is composed of a main body frame portion 9 as an immovable portion housing and a front frame 8 as a front housing. The front frame 8 is rotatably supported by a support shaft (not shown) and has an openable structure as shown in FIG. It's easy. At this time, the other image forming units do not move, and no troubles due to toner scattering or leakage occur.

Next, the image forming operation of this printer will be described. In FIG. 2, the surface of the photoconductor belt 1 is uniformly charged by the charging charger 4, and then the writing unit 5 scans and exposes it based on image information to carry an electrostatic latent image. This image information is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black color information. In addition, the operation exposure is
A laser beam L emitted from a semiconductor laser (not shown) is scanned and its optical path is adjusted by an optical device (not shown) based on these image information. The above-mentioned monochromatic electrostatic latent image carried on the surface of the photoconductor belt 1 is developed by a revolver developing device 6 which will be described later, in a laser exposure portion with a predetermined one-component non-magnetic toner of yellow, cyan, magenta and black, respectively. To be done. Then, the photosensitive belt 1
A toner image of each color is sequentially formed on the top. By using the one-component non-magnetic toner, it is possible to obtain a color toner image excellent in gradation of a highlight image and density uniformity of solid areas.

Further, each monochromatic toner image formed on the photosensitive belt 1 rotating in the direction of arrow A in the figure is sequentially transferred onto the intermediate transfer belt 10 by a predetermined transfer bias applied to the bias roller 13. . Specifically, on the intermediate transfer belt 10 that rotates in the direction of arrow B in the figure in synchronization with the photoconductor belt 1, the intermediate transfer belt 10 is sequentially transferred for each single color of yellow, cyan, magenta, and black by a predetermined transfer bias. Transcribed on. This transfer is sequentially performed so that the toner images of all four colors are superposed on the intermediate transfer belt 10. Each monochromatic toner image formed on the surface of the photosensitive belt 1 is affected by the pressing force of the bias roller 13 and the transfer bias when passing through the contact portion.
Then, the image is transferred onto the intermediate transfer belt 10 which rotates while being in contact with the photoconductor belt 1 in synchronization. When the toner images of all colors in the order of yellow, cyan, magenta, and black are superimposed and transferred onto the intermediate transfer belt 10, the image on the intermediate transfer belt 10 becomes a full-color image.

On the other hand, on the side of the paper feed cassette 17, the paper feed roller 18 is driven at the timing when a full-color image is formed on the intermediate transfer belt 10, and this drive causes the transfer paper 17A to be ejected from the paper feed cassette 17. To be paper. The ejected transfer paper 17A is transferred to the conveyance rollers 19a and 1
The full color image on the intermediate transfer belt 10 is collectively transferred by being conveyed between the intermediate transfer belt 10 and the transfer roller 14 through the space between the intermediate transfer belt 9 and the registration rollers 20a and 20b. Then, the full-color image is conveyed to the fixing device 80 and fixed, and the discharge rollers 81a and 81b are fixed.
It is ejected onto the printer paper stack portion 82 via the space between.

A cleaning blade 15a of the cleaning device 15 is in contact with the photosensitive belt 1 on the downstream side of the contact portion. As a result, the intermediate transfer belt 1
The residual toner that has not been transferred onto the surface of the photoconductor belt 1 is mechanically scraped off from the surface of the photosensitive belt 1. Then, the scraped toner is stored in the waste toner collecting container 15c of the cleaning device 15.

A similar cleaning device 16 is also in contact with the intermediate transfer belt 10, whereby the residual toner not transferred to the transfer paper 17A is mechanically scraped off from the intermediate transfer belt 10. . However, the cleaning blade 16a of the cleaning device 16 is held at a position separated from the surface of the intermediate transfer belt 10 during the image forming operation, and contacts the surface of the intermediate transfer belt 10 after the full color image is transferred onto the transfer paper 17A. Contact.

The waste toner scraped off by the cleaning blade 16a is conveyed forward by the auger 16b provided in the cleaning device 16. Further, the waste toner collecting container 15 is provided by a carrying unit (not shown) provided on the front side surface of the process cartridge 31.
It is transported to c. This printer is configured so that the process cartridge 31 is replaced when the waste toner of a predetermined amount or more is stored in the waste toner collecting container 15c, so that the life of the process cartridge 31 is extended. There is. The case exterior portion of the process cartridge 31 on the side of the registration roller 20b also has a function as a sheet conveyance guide.

Next, the photosensitive belt 1 and the intermediate transfer belt 10 used in the printer of this embodiment will be described in detail. First, the photosensitive belt 1 will be described. The photoreceptor belt 1 is a conductive seamless belt made of nickel or the like having a thickness of 25 to 40 [μm] and provided with an undercoat layer, a charge generation layer, a charge transport layer or a protective layer by a dip coating method, a spray coating method or the like. Is used.

The undercoat layer is provided for the purpose of improving the adhesiveness, preventing moire, improving the coating property of the upper layer, and reducing the residual potential. The undercoat layer generally contains a resin as a main component, but considering that the photosensitive layer on the resin is applied using a solvent, these resins are resins having high solubility in general organic solvents. Is desirable.
Examples of such resins include polyvinyl alcohol, casein, water-soluble resins such as sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane, melamine resin, alkyd-melamine resin, and epoxy resin. , And a curable resin that forms a three-dimensional network structure. In addition, titanium oxide, silica, alumina, zirconium oxide, tin oxide,
Fine powders of metal oxides such as indium oxide and the like, or metal sulfides and metal nitrides may be added. The layer thickness of the undercoat layer is preferably about 0.2 to 12 [μm].

The charge generating layer is a layer containing a charge generating substance as a main component, and a binder resin may be used if necessary. As the charge generating material, inorganic materials such as crystalline selenium, amorphous selenium, selenium-tellurium, phthalocyanine-based pigments, azo pigments, perylene-based pigments, anthraquinone-based or polycyclic quinone-based pigments, triphenylmethane-based organic pigments, etc. Materials can be used. These charge generating substances can be used alone or as a mixture of two or more kinds. The thickness of the charge generation layer is 0.01 to 5
[μm] is suitable, and preferably 0.05 to 2 [μm
m].

The charge-transporting layer is a layer intended to retain a charged charge, and to move the charge generated and separated in the charge-generating layer by exposure to combine with the retained charge. Examples of the charge transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives and triazole derivatives. These hole transport materials can be used alone or as a mixture of two or more kinds. The thickness of the charge transport layer is
About 5 to 100 [μm] is suitable. As the binder resin that can be used in combination with the charge transport layer, polycarbonate (bisphenol A type, bisphenol Z type), polyester, methacrylic resin, acrylic resin,
Examples include polyethylene, polyurethane, polyvinylidene chloride, silicone resin, and phenoxy resin. These binders can be used alone or as a mixture of two or more kinds. Bisphenol A type polycarbonate is preferable for the photosensitive belt 1 because of cracks in the photosensitive layer. If necessary, an appropriate amount of a plasticizer, an antioxidant, a leveling agent, etc. can be added in addition to the charge transport material and the binder resin.

A protective layer in which fine particles of metal or metal oxide are dispersed in the binder resin may be provided. A suitable thickness of the protective layer is about 0.1 to 10 [μm].

Next, the intermediate transfer belt 10 will be described. FIG. 1 is a partial cross-sectional view showing the structure of the intermediate transfer belt 10. The intermediate transfer belt 10 is composed of a base layer 92, an elastic layer 93, and a release layer 94.

The base layer 92 includes polycarbonate resin, polyimide resin, polyester resin, fluorine resin (ETFE, PVDF), polystyrene, styrene.
Styrene-based resins such as butadiene copolymers and styrene-vinyl chloride copolymers (styrene or homopolymers or copolymers containing styrene substitution products), methyl methacrylate resins, butyl methacrylate resins, ethyl acrylate resins,
Butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin,
Acrylic / urethane resin), polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, polyurethane resin, silicone resin, polyamide resin, etc. can be used. The elastic layer 93 includes butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-
Butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-
Polybutadiene, epichlorohydrin type rubber, recone rubber, fluororubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, thermoplastic elastomer (for example, polystyrene type, polyolefin type, polyvinyl chloride type, polyurethane type, polyamide type, polyurea) , Polyester-based, fluororesin-based, etc., can be used alone or in combination of two or more. However, it goes without saying that the base layer 92 and the elastic layer 93 are not limited to the above materials.

In order to adjust the resistance value of the base layer 92 and the elastic layer 93, carbon black, graphite,
Metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite oxide (ATO),
Conductive metal oxides such as indium oxide-tin oxide composite oxide (ITO) and conductive metal oxides may be added by coating with insulating fine particles such as barium sulfate, magnesium silicate and calcium carbonate. good. The thickness of the elastic layer is 0.
02-0.5 [mm] is preferable. When the thickness is 0.02 [mm] or less, the amount of deformation of the belt during transfer of the toner layer is small, and the effect of missing transfer is small. If it is 0.5 [mm] or more, the amount of deformation of the belt is too large and color misregistration easily occurs when the toner images are superposed.

As the release layer 94, a layer that reduces the adhesion of toner to the surface of the intermediate transfer belt and enhances the secondary transfer property is used, and the layer thickness is formed to 2 to 30 [μm]. .
As a material to be used, for example, one type or two or more types of polyurethane, polyester, epoxy resin or the like is used, and a material having a small surface energy to improve lubricity is used. For example, it is possible to use a powder of fluororesin, a fluorine compound, fluorocarbon, titanium dioxide, silicon carbide or the like, or one kind or two or more kinds of particles, and sometimes a dispersion of particles having different particle sizes. As a result, the surface layer of the intermediate transfer belt 10 is obtained. Further, as the surface layer material, a material having a fluorine-rich layer formed on the surface thereof by heat treatment such as a fluorine-based rubber material to reduce the surface energy can be used.

With the above configuration, the intermediate transfer belt 10
Has a thickness of 0.1 to 3 [mm] and a resistance value of 1 × 10 ⁶ to 1 × 1.
0 ¹⁵ [Ωcm] is preferable. When the resistance value of the intermediate transfer belt 10 is less than 1 × 10 ⁶ [Ωcm], the toner image is largely disturbed during transfer, and when it exceeds 1 × 10 ¹⁵ [Ωcm], toner layer transfer failure occurs.

As a method of manufacturing the intermediate transfer belt 10 having the above structure, a belt manufacturing method using a mold as shown below is known. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which the material is sprayed onto the cylindrical mold to form a thin film on the surface layer, and a cylindrical mold is used to form a solution of the material. There is a dip coating method in which the product is dipped in and pulled up. Furthermore, there are a casting method in which a material is injected between an inner die and an outer die, and a method in which a compound is wound around a cylindrical die and vulcanized and polished. Further, the belt is not limited to any one of these methods, and the belt can be manufactured by combining a plurality of manufacturing methods. Further, in these manufacturing methods, in order to improve the releasability of the intermediate transfer belt from the mold, the peripheral length difference is provided at both ends of the mold so that the peripheral lengths of the both end portions in the belt width direction are different. This circumference difference is generally set to 0.05 [mm] or more. This is because if the circumferential length difference is smaller than this, it becomes difficult to release from the mold. Further, a method of using a releasing agent to improve the releasing property from the mold is also conceivable, but if this is frequently used, belt slip due to the releasing agent attached to the back surface of the intermediate transfer belt,
Since the surface state of the intermediate transfer belt becomes unfavorable due to deterioration of the back surface and the like, the circumferential length difference of 0.05 mm or more is necessary. On the other hand, the upper limit of circumference difference is 0.31 [m
m] was set. Perimeter difference is the upper limit 0.3
This is because if it exceeds 1 [mm], unevenness of primary transfer of the toner image from the photoconductor is likely to occur.

Then, the intermediate transfer belt 10 of the present embodiment.
Has a circumferential length difference at both ends of a mold used for manufacturing, and the belt itself also has a circumferential length difference at both end portions in the width direction, so that the following problems are likely to occur. That is, when the elastic intermediate transfer belt 10 having the circumferential length difference at both ends in the width direction is stretched over a plurality of rollers and driven,
Occasionally, the intermediate transfer belt 10 is wavy. When the intermediate transfer belt 10 is wavy in the printer, transfer failure may occur in the primary transfer image or the secondary transfer image. In addition, transfer failure may occur due to transfer failure of the intermediate transfer belt due to undulation. Therefore, in the present embodiment, a reinforcing member is provided on the intermediate transfer belt 10 so that a transfer failure does not occur even if such an intermediate transfer belt 10 is used. Hereinafter, the characteristic part of this embodiment will be described in more detail.

FIG. 1 shows an intermediate transfer belt 10 used in this embodiment. Seamless reinforcing members 91 are provided on the back surfaces of both ends of the intermediate transfer belt 10. The seamless reinforcing member 91 is a seamless member whose outer periphery has the same peripheral length as the inner peripheral surface of the intermediate transfer belt. Since the intermediate transfer belt 10 has different circumferential lengths at both ends in the width direction, the seamless reinforcing members 91 have different circumferential lengths. The seamless reinforcing member 91 has a tension of 1.96.
The elongation at [N / cm] is preferably 0.02 [%] or less and the thickness is preferably 100 [μm] or less. As a material forming the seamless reinforcing member 91, nickel,
Metals such as stainless steel, copper and beryllium copper, and resins having a high elastic modulus such as polyimide are preferable. A seamless reinforcing member 91 made of a metal such as nickel is disclosed in JP-A-3-219259.
No. 63-127250, 63-127
249, Japanese Patent Publication No. 52-36016, and Japanese Patent Publication No. 52
It can be formed by the electroforming method disclosed in, for example, -8774. The seamless reinforcing member 91 formed by this is attached to the inner peripheral surface of the intermediate transfer belt 10 with an adhesive or an adhesive, or the seamless reinforcing member 91 is previously attached to a mold when the intermediate transfer belt 10 is molded. It may be molded integrally.

Further, in the intermediate transfer belt 10 of the present embodiment, a detent member 95 is further provided on the seamless reinforcing member 91 to prevent the belt from deviating when the belt is driven, which will be described later. Detailed description. As described above, since the offset preventing member 95 is provided, the width of the bias roller (not shown) for applying the voltage to the intermediate transfer belt 10 is provided while leaving a region for providing the offset preventing member 95 on the back surface of both ends of the belt. There is a need. Therefore, it is necessary to make the width smaller than the width of the intermediate transfer belt 10. Further, the bias roller needs to be out of contact with the seamless reinforcing member 91, and in consideration of the transportability of the intermediate transfer belt 10, the range in which the bias roller is provided is 15 from both ends of the back surface of the belt.
The central area of the belt to the inside of [mm] is preferable. Further, the width of the seamless reinforcing member 91 is preferably less than 15 [mm]. If the seamless reinforcing member 91 comes in from the both ends of the back surface by more than 15 [mm], the seamless reinforcing member 91 may come into contact with the bias roller of the intermediate transfer belt 10, and the end portion may be disturbed when the toner image is transferred.

Next, the deviation preventing member 95 will be described. FIG. 3 is a cross-sectional view of the intermediate transfer belt 10 when the offset preventing members 95 are provided on the inner surfaces of the seamless reinforcing members 91 provided at both ends of the back surface of the intermediate transfer belt 10. The rubber hardness (JIS-A) of the anti-shift member 95 is preferably 50 to 90. The detent member 95 may be provided with a primer (not shown) and bonded to the seamless reinforcing member 91.
The thickness of the primer is preferably 5 to 30 [μm]. If the thickness of the primer is less than 5 [μm], the primer cannot be applied uniformly due to the surface roughness Rz of the anti-shift member 95, and a part where the anti-shift member 95 is exposed occurs, so that the adhesive property between the anti-shift member 95 and the adhesive agent is increased. Will fall. The material of the anti-slip member 95 is not particularly limited as long as it has appropriate rubber elasticity and does not deteriorate due to the environment in the image forming apparatus. For example, polyurethane rubber, neoprene rubber, urethane rubber, chloroprene rubber, nitrile rubber,
Examples thereof include synthetic rubbers such as butyl rubber and silicone rubber, and rubbers such as one kind or a mixture of two or more kinds of natural rubbers. Above all, urethane rubber is most preferable because it has low stability against temperature and humidity, low abrasion resistance, and excellent ozone resistance. Further, the surface roughness Rz of the side surface of the pressure-sensitive adhesive of the offset member 95 is preferably 2 to 15 [μm].

The thickness of the detent member 95 is 0.6 to 3 [m].
m] and the width is preferably 3 to 10 [mm]. Thickness 0.6 [m
If it is less than m], the intermediate transfer belt 10 is likely to run on the roller. Further, if the thickness exceeds 3 [mm], there is a problem that when the anti-shift member 95 is attached to the intermediate transfer belt 10, the internal stress of the anti-shift member 95 increases and the adhesiveness of the anti-shift member 95 deteriorates. is there. Further, if the width is less than 3 [mm], the adhesive area is insufficient, and when the intermediate transfer belt 10 is repeatedly used, the pressure-sensitive adhesive cannot withstand the offset force of the intermediate transfer belt 10 and the offset member 95 is displaced. Further, when the width exceeds 10 mm, when the detent member 95 is attached to the intermediate transfer belt 10, the detent member 95 is attached in an extended state, which makes it difficult to hold the cylindrical shape of the belt. The ends tend to be partially indented.

The detent member 95 is used for the intermediate transfer belt 10.
Is preferably provided on the back surface side up to 5 [mm] from the end in the longitudinal direction. If the gap from the end portion exceeds 5 [mm], kinks (belt of the belt) or the like are likely to occur at the end portion of the intermediate transfer belt 10 when assembling a unit by inserting a plurality of rollers inside the intermediate transfer belt 10. Become. Moreover, it is preferable that the anti-slip member 95 contains a filler. As the filler, it is preferable to mix a filler such as carbon, calcium silicate, calcium carbonate, and glass fiber. Mixing of the filler is preferable because it can control the surface roughness of the elastic body and improve mechanical properties (rubber hardness, 300% modulus, structural strength, etc.) of the elastic body. Further, among the fillers, the incorporation of a carbon body such as carbon black is particularly preferable from the viewpoints of controlling the surface roughness and improving the mechanical properties. This is because the frictional force with the drive roller can be reduced by the lubricating effect of the carbon body,
The force applied from the rotating roller 11 as a driving roller is reduced. Therefore, when the intermediate transfer belt 10 is repeatedly used, meandering of the anti-shift member 95 hardly occurs, which is very preferable. The content of the filler is not particularly limited, but may be 1 to 50%, preferably 3 to 40%, and particularly preferably 5 to 30% of the total weight of the elastic body. Rotating rollers 11 and 12 are made by molding a rubber material such as EPDM or chloroprene around a cored bar (not shown) and polishing the surface, and a cored bar (not shown) coated with a urethane resin. Etc. are used.

Next, another attachment state different from the attachment state of the seamless reinforcing member 91 shown in FIG. 2 will be described with reference to FIG. In FIG. 4, notches having the same depth as the seamless reinforcing member 91 are formed at both ends of the base layer 92 on the back surface of the intermediate transfer belt 10, and the seamless reinforcing member 91 is fitted in the recess. As a result, even when the seamless reinforcing member 91 is attached, the seamless reinforcing member 91 and the base layer 92 are flat. After that, the anti-shift member 95 is provided. In this way, either the inner peripheral surface of the intermediate transfer belt is made flat or, as shown in FIG. 3, the seamless reinforcing member 91 is projected slightly to the inner peripheral surface of the intermediate transfer belt, whichever is selected. To do.

Hereinafter, Examples 1 to 5 according to the present invention in which the seamless reinforcing member 91 is provided on the inner peripheral surface of the intermediate transfer belt as described above, and Comparative Examples 1 to 7 will be shown.
In the following description, "part" means part by weight and "perimeter" means inner circumference.

[Embodiment 1] An example of a method for manufacturing the intermediate transfer belt used in the present embodiment 1 will be described. A mixture of 20 parts of polyurethane elastomer, 15 parts of conductive titanium oxide (ET-500W: manufactured by Ishihara Sangyo) and 120 parts of DMF (manufactured by Kanto Scientific Co., Ltd.) is placed in a ball mill pot. And φ10 [mm] Y
The coating solution was prepared by ball milling for 48 hours using TZ balls. This coating solution is spray-coated on the outer peripheral surface of a carbon-dispersed polyurethane base layer produced by a centrifugal molding method, dried at 130 [° C.] for 40 minutes, and a thickness of 150 is obtained.
An elastic layer of [μm] was formed. This carbon-dispersed polyurethane base layer has a width of 383 [mm] and a peripheral length of 587 [m.
m], circumference difference between left and right 0.05 [mm], thickness 350 [μ
m]. Then 20 parts of polyurethane elastomer,
5 parts of conductive titanium oxide (ET-500W: made by Ishihara Sangyo),
10 parts of tetrafluoroethylene resin powder (L-2 Daikin),
A dispersion liquid consisting of 155 parts of DMF (manufactured by Kanto Kagaku Co., Ltd.) was spray coated on the belt, dried at 130 [° C.] for 20 minutes, and an intermediate transfer belt 1 having a release layer with a thickness of 10 μm
0 was created. Next, about 30 [μm] of acrylic adhesive was applied in advance from the end of the inner surface of the intermediate transfer belt to a width of 9 [mm]. A seamless reinforcing member 91 composed of two nickel seamless belts having a width of 10 [mm], a thickness of 30 [μm], and a peripheral length of 586.62 [mm] and 586.67 [mm] is attached to this surface. did. Then width 4 [mm], thickness 0.8 [mm]
Non-stop member 95 (rubber hardness 70, surface roughness Rz12
A reaction-curable urethane primer was spray-coated on a [μm] carbon-dispersed urethane rubber to a film thickness of 20 [μm].
Further, an acrylic adhesive of 30 [μm] was applied to provide an adhesive layer) was attached to the seamless reinforcing member 91 with a gap of 1 [mm] from the back end of the intermediate transfer belt. The sticking accuracy measured with a caliper was 0.3 [mm]. Incidentally, the sticking start portion and the end portion of the offset prevention member 95 were provided with an oblique cut of about 45 degrees, and the gap was about 2 [mm].

[Example 2] In Example 1, the carbon-dispersed polyurethane base layer has a circumferential length difference of 0.16 between the left and right sides.
An intermediate transfer belt 10 was formed in exactly the same manner as in Example 1 except that the thickness was changed to [mm]. The seamless reinforcing member 91 has a width of 10 [mm], a thickness of 30 [μm], and a peripheral length of 586.
Two nickel seamless belt-shaped reinforcing members of 62 [mm] and 586.78 [mm] were attached. Anti-slip member 9
As for No. 5, the same thing as Example 1 was stuck.

[Third Embodiment] In the second embodiment, the anti-shift member 95 has a rubber hardness of 7 [mm] and a width of 4 [mm].
5, the surface roughness was changed to Rz15 [μm]. Except for this, the seamless reinforcing member 91 and the offset preventing member 95 were formed on the intermediate transfer belt in the same manner as in Example 2.

[Embodiment 4] In Embodiment 1, the carbon-dispersed polyurethane base layer has a circumferential length difference of 0.12 between the left and right sides.
An intermediate transfer belt 10 was formed in exactly the same manner as in Example 1 except that the thickness was changed to [mm]. Next, the width is 12 [mm], the thickness is 80 [μm], and the perimeter is 586.31 [mm] and 586.
43 [mm] of two polyimide seamless reinforcing members 91 (manufactured by Nitto Denko) were coated with 10 phenoxy primers.
Spray coating was applied to a film thickness of [μm]. An acrylic pressure-sensitive adhesive was applied to this by 20 [μm] to form an adhesive layer, and the adhesive was applied with a gap of 1 [mm] from the end of the inner surface of the intermediate transfer belt. As the anti-slip member 95, the same thing as in Example 1 was stuck in exactly the same manner as in Example 1 with a gap of 1.5 [mm] from the back end of the intermediate transfer belt.

[Embodiment 5] The difference in circumferential length between the left and right sides formed by the casting method is 0.12 mm, the width is 10 mm at both ends, and the depth is 6.
An intermediate transfer belt 10 having an elastic layer and a release layer was formed on the base layer having a cutout of 0 [μm] in the same manner as in Example 1. Then, in this example, a notch having a depth of 60 [μm] was formed in the base layer, and an acrylic adhesive of about 30 [μm] was applied to the recess. After this, the thickness is 30 [μm] and the perimeter is 586.62 [mm] and 586.
A seamless reinforcing member 91 composed of two 74 mm seamless nickel seamless belts was attached. Therefore, in the fifth embodiment, the seamless reinforcing member 91 and the base layer 92 are flat. Further, as the anti-slip member 95, the same thing as in Example 1 was stuck in exactly the same way as in Example 1.

Next, a comparative example prepared for the above embodiment will be described. [Comparative Example 1] In Example 1, the base layer has a width of 383 [m].
m], circumferential length difference between left and right 0.33 [mm], thickness 350 [μ
[m] was used, and an intermediate transfer belt 10 was formed in exactly the same manner as in Example 1 except that the carbon-dispersed polyurethane base layer was used. Subsequently, an acrylic pressure-sensitive adhesive was applied in advance to the width of 9 [mm] from the end of the inner surface of the intermediate transfer belt by about 30 [μm]. The coated surface has a width of 10 [mm], a thickness of 30 [μm] and a perimeter of 58.
Seamless reinforcement member 91 composed of two nickel seamless belts of 6.62 [mm] and 586.95 [mm]
Was pasted. Further, as the anti-slip member 95, the same thing as in Example 1 was stuck in exactly the same way as in Example 1.

[Comparative Example 2] The intermediate transfer belt 10 is formed in the same manner as in Example 2 except that the seamless reinforcing member 91 is not provided.
Was pasted.

Comparative Example 3 An intermediate transfer belt was carried out in the same manner as in Example 4 except that the seamless reinforcing member 91 in Example 4 was changed to a nickel seamless belt having a thickness of 110 [μ] and a width of 10 [mm]. Formation of 10 and stop member 95
Was pasted.

[Comparative Example 4] The intermediate transfer belt 10 was prepared in the same manner as in Example 2 except that the urethane rubber of the offset member 95 was changed to rubber hardness 40.
I made a book.

[Comparative Example 5] Two intermediate transfer belts 10 were prepared in the same manner as in Example 2 except that the urethane rubber of the offset member 95 in Example 2 was changed to a rubber hardness of 100.

[Comparative Example 6] In Example 2, the seamless reinforcing member 91 was made of polyester having a width of 10 [mm], a thickness of 50 [μm], and a peripheral length of 586.50 [mm] and 586.66 [mm]. Made into a seamless belt. Except for this, the intermediate transfer belt 10 was formed and the anti-shift member 95 was attached in the same manner as in Example 2.

[Comparative Example 7] Nickel having a width of 10 mm, a thickness of 10 [μm] and a peripheral length of 586.75 [mm] and 586.91 [mm] in the seamless reinforcing member 91 in Example 2. I changed it to a seamless belt. Except for this, the intermediate transfer belt 10 was formed and the anti-shift member 95 was attached in the same manner as in Example 2.

Further, a specific manufacturing example of the photosensitive belt 1 used in the printer of this embodiment will be described. Titanium oxide (CR-60: made by Ishihara Sangyo) 50
Part, alkyd resin (Beckolite M6401-50 manufactured by Dainippon Ink and Chemicals) 15 parts, melamine resin (Super Beckamine L-121-60 manufactured by Dainippon Ink and Chemicals) 8.3 parts, methyl ethyl ketone (manufactured by Kanto Chemical) 3
Put the mixture consisting of 1.7 parts in a ball mill pot and φ1
Ball milling was carried out for 72 hours using 0 [mm] alumina balls. To this milling solution, 105 parts of cyclohexanone (manufactured by Kanto Chemical Co., Inc.) was added and ball milling was further performed for 2 hours to prepare an undercoat layer coating solution. This coating solution has a circumference of 290.
3 [mm], left and right circumference length difference 0.16 [mm], length 367
It was spray-coated on a nickel seamless belt of [mm] and thickness of 30 [μm]. Further, it was dried at 135 [°] C. for 25 minutes to form an undercoat layer having a film thickness of 6 μm.

Subsequently, the following mixture was placed in a ball mill pot and ball-milled for 20 hours using YTZ balls of φ10 [mm], and then 78.4 parts of cyclohexanone and 237.6 parts of methyl ethyl ketone were added to prepare a charge generation layer coating solution. It was adjusted. The mixture is 2 parts of a charge generating substance of Chemical formula 1 (manufactured by Ricoh), 1 part of a charge generating substance of chemical compound 2 (manufactured by Ricoh), 1 part of polyvinyl butyral resin (S-REC BLS; manufactured by Sekisui Chemical), cyclohexanone (manufactured by Kanto Chemical). ) 80 parts. This coating solution was spray-coated on the undercoat layer and dried at 130 [° C.] for 20 minutes to form a charge generation layer having a thickness of 0.1 μm.

[Chemical 1]

[Chemical 2]

Next, a coating solution for the charge transport layer was prepared, and this coating solution was spray-coated on the charge generation layer, and the coating was carried out at 130 [° C.] for 30 minutes.
After drying for a minute, an endless belt-shaped photoreceptor having a charge transport layer having a thickness of 25 [μm] was formed. The charge transport layer coating liquid is 7 parts of a charge transport substance (the following formula (formula 3)) (manufactured by Ricoh), 10 parts of a polycarbonate resin (C-1400, manufactured by Teijin Chemicals),
Silicone oil (KF-50, manufactured by Shin-Etsu Chemical) 0.00
2 parts, tetrahydrofuran (Kanto Chemical Co., Ltd.) 76.5 parts,
Cyclohexanone (Kanto Kagaku) 76.5 parts, 2,5-di-tert-butylhydroquinone (Tokyo Kasei) 0.0
It consists of two parts. Further, the same anti-slip member 95 as in Example 1 was provided on the back surfaces of both ends of the photoconductor.

[Chemical 3]

The intermediate transfer belt 10 and the photoconductor belt 1 of Examples 1 to 5 and Comparative Examples 1 to 7 thus prepared were attached to the printer shown in FIG. 2 to print a gray halftone color image and a grid pattern. I went. At this time, the tension applied to the intermediate transfer belt 10 is 0.6 [N / cm],
Writing density 600D with laser light of wavelength 655 [nm]
PI and 1200 DPI, and a linear velocity of 120 [mm / sec] was set in an environment of 27 [° C.] and 80 [%]. Subsequently, the image forming apparatus is operated in the free run mode (the image forming process is repeated without passing the transfer paper), and the gray halftone color image is printed for every 1000 full color sheets.
The evaluation was performed up to 10,000 sheets. The elongation at a tension of 1.96 [N / cm] is a universal tensile compression tester (TCM200CR type:
It was measured by using Minebea). The results are shown in Table 1.

[Table 1]

From the results shown in Table 1, the following was found.
When the second embodiment and the second comparative example are compared with each other and the seamless reinforcing member 91 is provided on the intermediate transfer belt 10 as in the second embodiment, the transfer omission caused by the corrugation of the belt does not occur. On the other hand, in the case where the seamless reinforcing member 91 is not provided as in Comparative Example 2, even if the other configurations are the same as those in Example 2, the transfer omission occurs when the number of sheets reaches about 15,000. It started to occur frequently. Therefore, it can be said that the provision of the seamless reinforcing member 91 has an effect of preventing the transfer failure. Further, in Comparative Example 2, cracking occurred at the end portion of the intermediate transfer belt at about 10,000 sheets. Therefore, it can be said that the provision of the seamless reinforcing member 91 can prevent the end portion of the intermediate transfer belt from being cracked. However, as in Comparative Example 1, when the circumferential length difference between the both ends of the intermediate transfer belt is 0.33 [mm], which exceeds the usual upper limit of 0.31 [mm], the seamless reinforcing member 91 is provided. However, the transfer omission occurred from the beginning. This is because if the difference in circumferential length is too large, it is not possible to prevent undulation of the intermediate transfer belt due to driving. Therefore, it is desirable that the difference in circumferential length is within a normal range of 0.05 to 0.31 [mm]. Further, in Comparative Example 3, the thickness of the seamless reinforcing member 91 is set to 110 [μm] which is thicker than those of the other Examples 1 to 5 and Comparative Examples 1, 2 and 4 to 7. As a result, defective winding around the roller of the intermediate transfer belt 10 occurred, and white spots occurred at the image end. Further, as in Comparative Examples 6 and 7, when the elongation percentage of the seamless reinforcing member 91 is higher than 0.02 [%], the transfer omission occurs when the number of sheets reaches 25,000 sheets and 550,000 sheets, respectively. It started to occur frequently. Further, the color shift on the intermediate transfer belt 10 is 600 DPI, 1200 D
Each PI occurred as shown in the table. In Examples 1 to 5 in which the seamless reinforcing member 91 has an elongation rate of 0.02 [%] or less and a thickness of 100 [μm] or less,
Neither winding defects on the roller nor missing transfer occurred.
Therefore, the elongation rate of the seamless reinforcing member 91 is 0.02.
By setting the thickness to 100% or less and the thickness to 100 [μm] or less, defective winding around the roller and transfer omission can be prevented. In addition, among Examples 1 to 5, only Example 5 is configured such that the inner peripheral surface of the intermediate transfer belt after the seamless reinforcing member 91 is provided is flat. by this,
In Example 5, no abnormal image was generated in the transferred image up to 140,000 sheets. On the other hand, in Examples 1 to 4, the seamless reinforcing member 9 was added to the highlight image after about 80,000 sheets.
The traces of the step of No. 1 became streaky and were slightly seen. Therefore, by flattening the inner peripheral surface of the intermediate transfer belt after the seamless reinforcing member 91 is provided, the traces of the seamless reinforcing member 91 are less likely to be attached to the image, and the streak-like image caused by the step is not generated. It can be reduced. In addition, as in Comparative Example 4, the rubber hardness (JIS
-If A) is set to 40, 600 DPI, 1200 DPI
In either case, the character misalignment and thickening can be visually observed, and if it is less than 50, abrasion of the deviation prevention member 95 becomes a problem. On the other hand, if the rubber hardness of the anti-slip member 95 is set to 100, a color shift will occur from the beginning at 600 DPI, and
At 0DPI, some banding occurred from the beginning. This is because if it exceeds 90, it is easy to get on the roller. Further, when it exceeds 90, the adhesive force with the seamless reinforcing member 91 tends to be lowered at the front and rear end portions of the anti-shift member 95. The rubber hardness of the stopper member 95 is 50.
In Examples 1 to 5 in which the number is 90 or more, such a problem did not occur. Therefore, by providing the offset preventing member 95 having a rubber hardness of 50 to 90, it is possible to reduce the occurrence of color misregistration and banding. Further, in Examples 1 to 5, the intermediate transfer belt 10 provided with the seamless reinforcing member 91 is used in a color image forming apparatus for sequentially primary-transferring images of a plurality of colors onto the intermediate transfer belt 10. As a result, it is possible to prevent undulation and driving failure caused by undulation when the intermediate transfer belt 10 is driven, and it is possible to prevent color misregistration, and thus it is possible to form a good color image.

[0059]

According to the image forming apparatus of the first to sixth aspects of the present invention, it is possible to almost constantly prevent undulation when driving the intermediate transfer belt and drive failure of the intermediate transfer belt due to undulation. Therefore, in the image forming apparatus using the elastic intermediate transfer belt having the circumferential length difference between both ends in the width direction, it is possible to almost constantly prevent the transfer failure caused by the waviness of the intermediate transfer belt or the drive failure. effective.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of an intermediate transfer belt.

FIG. 2 is a schematic configuration diagram showing a cross section of the printer of the present embodiment.

FIG. 3 is a sectional view of an intermediate transfer belt showing an example of the intermediate transfer belt according to the present embodiment.

FIG. 4 is a sectional view of an intermediate transfer belt showing another example of the intermediate transfer belt according to the present embodiment.

[Explanation of symbols]

1 photoconductor belt 4 Charger 5 writing unit 6 Revolver developing device 10 Intermediate transfer belt 13 Bias roller 14 Transfer roller 15, 16 Cleaning device 17 Paper feed cassette 31 process unit 80 Fixing device 91 Seamless reinforcement member 92 Base layer 93 Elastic layer 94 Release layer 95 Offset member

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H200 FA10 FA16 GA24 GA34 GA47                       GB12 GB25 GB43 GB44 HA02                       HB12 HB22 JA02 JB10 JC04                       JC10 JC12 JC13 JC15 JC17                       LA25 LC03 LC04 LC08 MA01                       MA02 MA03 MA12 MA13 MA14                       MA17 MA20 MC02 MC03                 2H300 EB02 EB13 EC02 EC05 EC09                       EF03 EF08 EH16 EH25 EH27                       EJ09 EJ15 EJ47 EL04 GG22                       GG38 GG48 HH25 HH36 JJ02                       JJ03 JJ05 KK02 KK03 KK05                       KK08 KK12 KK13 MM02 MM04                       NN01

Claims (6)

[Claims] 1. An image bearing member carrying a latent image on its surface, a developing means for developing the latent image on the image bearing member, and an image formed on the image bearing member is primarily transferred onto an intermediate transfer member. Which is an endless belt having elasticity as the intermediate transfer member, and a secondary transfer unit for secondarily transferring the primary transfer image on the intermediate transfer member onto the transfer material. In an image forming apparatus using a transfer belt, a reinforcing member for reinforcing the intermediate transfer belt is provided on the inner peripheral surface of the intermediate transfer belt, and an endless seamless seamless reinforcing member is used as the reinforcing portion. An image forming apparatus characterized by. 2. The image forming apparatus according to claim 1, wherein the seamless reinforcing members are provided at both ends in the width direction of the inner peripheral surface of the intermediate transfer belt, and the seamless reinforcing members are made of metal and have a tension of 1. An image forming apparatus characterized in that an elongation at 96 [N / cm] is 0.02 [%] or less and a thickness is 100 [μm] or less. 3. The image forming apparatus according to claim 1, wherein the inner peripheral surface of the intermediate transfer belt in the state where the seamless reinforcing member is provided is flat. 4. The image forming apparatus according to claim 1, 2, or 3, wherein the seamless reinforcing member is provided with a detent member for preventing a belt deviation when the intermediate transfer belt is driven. Image forming apparatus. 5. The image forming apparatus according to claim 4, wherein the deviation preventing member has a hardness of 50 or more and 90 or less. 6. The image forming apparatus according to claim 1, 2, 3, 4, or 5, wherein the developing means is capable of developing a plurality of latent images of different colors with toner, and the primary transfer means comprises: The toner images of different colors formed by the developing means are sequentially primary-transferred onto the intermediate transfer belt so that a superimposed toner image can be formed on the intermediate transfer belt. Image forming apparatus.