JP2002012681A - Seamless belt, method fore producing the seamless belt and apparatus for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive seamless belt comprising a single layer and used for the imaging process of an imaging apparatus and provide an imaging apparatus such as a copy machine and the like. SOLUTION: This seamless belt has a base material consisting of a single layer having different properties on the front face and the rear face caused by the uneven distribution of an additive in the thickness direction. The base material consisting of the single layer having different properties on the front face and the rear face is formed by mixing the additive in a matrix solvent and forming the mixture under centrifugation. The seamless belt is used in either one of image forming processes and the seamless belt comprises the base material having different properties in the front and rear faces caused by uneven distribution of the additive in the thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a seamless belt, a method for manufacturing a seamless belt, and an image forming apparatus such as a copying machine, a facsimile, an electrophotographic apparatus, and a printer.

[0002]

2. Description of the Related Art Conventionally, various endless belts are frequently used in image forming apparatuses such as copying machines, facsimile machines, electrophotographic apparatuses, and printers to perform charging, transfer, intermediate transfer, sheet conveyance, fixing, and the like. .

In recent years, as colorization has progressed, the intermediate transfer system in which a toner image is temporarily transferred from a photoreceptor to an intermediate transfer belt and finally transferred to a recording medium such as paper has high image quality. In addition, attention has been paid to the advantage that images can be transferred regardless of the type and thickness of paper such as envelopes, postcards, and labels, and the demand for intermediate transfer belts is expected to increase in the future.

In order to maximize the advantages of the intermediate transfer system, it is necessary to ensure sufficient pressure and adhesion at the nip between the intermediate transfer belt and the secondary transfer roll. Therefore, if the intermediate transfer belt is formed of a flexible rubber in consideration of only the adhesiveness, misregistration and color misregistration of the toner image occur at the time of primary transfer for transferring a toner image of a plurality of colors, so that a high quality image can be obtained. I can't.

Therefore, an intermediate transfer belt which satisfies both elasticity and adhesiveness has been developed by using a polyimide material having a high modulus and little color shift and covering the surface with an elastic layer such as a silicone resin. However, this method requires expensive raw materials and further costs for laminating the elastic layer.

As a variety of endless belts used in an image forming apparatus, a "conductive seamless belt" having a laminated structure having a rigid and inexpensive elastic layer (JP-A-5-1052)
No. 59) has been proposed.

FIG. 1 is a schematic sectional view of the proposed conductive seamless belt.

As shown in FIG. 1, in this conductive seamless belt, the surface layer 30 is a conductive polyvinylidene fluoride resin having a high elastic modulus, and the intermediate layer 31 is a conductive acrylic resin bonding the surface layer and the inner layer. The inner layer 32 is made of a hardly stretchable conductive polycarbonate resin, and is manufactured by a co-extrusion method in which three layers are laminated in a molten state in one die and then continuously melt-extruded.

This conductive seamless belt has a laminated structure in which layers having different properties are laminated, so it is difficult to elongate, hardly deform, hardly cause cracks, and is durable. Polishing and grinding processes cannot be ignored. Further, an “endless belt” in which an elastic layer is formed on the surface and a reinforcing material such as a film is laminated (Japanese Unexamined Patent Publication No.
1-77845) has also been proposed.

FIG. 2 is a schematic sectional view of the proposed endless belt.

As shown in FIG. 2, this endless belt is made of an elastic layer 35 made of resin such as urethane or rubber.
A coating film 33 containing a fluororesin or the like is provided thereon, and while the coating film 33 is not dried, the reinforcing film 34 is pressed to embed the film 34 in the coating film, and the film 34 is adhered to the elastic layer 35 to manufacture. Is done. This endless belt has the advantage that the mechanical strength is ensured by the reinforcing film 34, but on the other hand, the man-hour required for bringing the film into close contact and laminating cannot be ignored, and the possibility of adhesive peeling at the laminating interface is completely eliminated. I can't wipe it out.

Further, as an intermediate transfer belt of the image forming apparatus, an "intermediate transfer belt" is used in which an elastic material is used and a reinforcing member made of fiber is inserted inside the elastic material to reinforce the intermediate transfer belt (Japanese Patent Application Laid-Open No.
0-240020) has been proposed.

FIG. 3 is a schematic sectional view of the proposed intermediate transfer belt.

As shown in FIG. 3, this intermediate transfer belt has an elastic layer 36 made of rubber or the like and a coating layer 38 containing a fluororesin powder, and the inside of the elastic layer 36 is made of polyester fiber or nylon fiber. The reinforcing fiber member 37 is inserted and reinforced.

FIG. 4 is a schematic perspective view of a reinforcing fiber member shown enlarged as an example.

As shown in FIG. 4, the reinforcing fiber member 37 is in the form of a woven fabric 38. If the distance between adjacent fibers is small, the fibers become an insulating layer and the transfer bias is not efficiently transmitted to the belt surface. Therefore, transfer may be difficult.

This belt has the advantage that color shift and surface cracks can be prevented, but the reinforcing effect cannot be obtained if the fiber as the reinforcing member is thin, and if the fiber is too thick, the thickness of the elastic member cannot be reduced. And smooth driving becomes difficult. In addition, if the fibers are too thick or if the spacing between the fibers is large, irregularities occur on the belt surface, which causes image defects.

[0018]

Generally, an endless belt is stretched by a plurality of drive rollers with a predetermined tension and circulates, and therefore requires a predetermined strength in accordance with a place to be used and a purpose.

Some image forming apparatuses include a transfer belt and a charging belt that require conductivity, and a transport belt and a fixing belt that require close contact with paper. There is also.

Therefore, it is convenient if the strength of the belt having a width depending on the place and purpose to be used can be satisfied without changing the manufacturing process and the material to be used, and in addition, it satisfies specific conditions such as conductivity and adhesion. It would be very effective if we could do it.

In particular, the intermediate transfer method has an advantage that the final transfer is not limited to a prescribed sheet, but can be transferred to recording media of various thicknesses and sizes from envelopes to postcards, label sheets and cardboard. There is an urgent need to develop products that satisfy predetermined conditions with inexpensive materials that can be used in general for endless belts in order to respond to future needs.

On the other hand, "conductive seamless belts" and "endless belts" have been proposed as belts satisfying the conditions using relatively inexpensive materials. However, the number of steps required for surface treatment after molding and the number of steps required for lamination are reduced. The latter cannot be ignored, and the latter also has a structural problem that the risk of peeling off of the laminate interface due to bending stress fatigue during operation cannot be completely eliminated. Also, an "intermediate transfer belt" has been proposed, in which woven fabric-like fibers are reinforced inside a single elastic material, but the thickness of the fibers is closely related to the thickness and strength of the belt. Further, there is a problem that the fiber spacing is deeply related to the conductivity of the belt.

In view of the above circumstances, the present invention provides a low-cost seamless belt composed of a single layer that satisfies requirements such as strength, adhesion, and conductivity required for an endless belt, a method for manufacturing the seamless belt, and an image forming method. An object of the present invention is to provide an image forming apparatus using the seamless belt in any one of the processes.

[0024]

Means for Solving the Problems A seamless belt according to the present invention for achieving the above object has a base material comprising a single layer having different properties between the front surface and the back surface due to uneven distribution of the additive in the thickness direction. Features.

It is preferable that the additive comprises a mixture of plural kinds of fillers having different average shapes.

Further, the method for producing a seamless belt according to the present invention, which achieves the above object, is a method for producing a seamless belt having a base material comprising a single layer, wherein an additive is mixed in a matrix solvent, and the mixture is centrifugally molded to obtain a thickness direction. Is characterized in that a base material composed of a single layer having different properties on the front surface and the back surface is formed due to uneven distribution.

In addition, the base material forming the seamless belt after being manufactured as a seamless belt forms a single layer having different properties between the front surface and the back surface due to uneven distribution of the additive in the thickness direction. Is preferably adjusted.

According to the image forming apparatus of the present invention for achieving the above object, a toner image is formed on an image carrier, and the toner image is finally transferred and fixed on a predetermined recording medium. In an image forming apparatus that forms an image composed of a fixed toner image on the recording medium, a seamless belt is used in any of the image forming processes. It is characterized by having a base material consisting of a single layer having different properties on the back surface.

Further, a toner image is formed on the image carrier,
In an image forming apparatus for forming an image composed of a fixed toner image on the recording medium by finally transferring and fixing the toner image on a predetermined recording medium, the toner formed on the image carrier Upon receiving the image transfer, the toner image is
A base material comprising an intermediate transfer belt for conveying to a secondary transfer device for secondary transfer to a predetermined recording medium, wherein the intermediate transfer belt is a single layer having different properties between the front surface and the back surface due to uneven distribution of the additive in the thickness direction And a seamless belt having a protective layer made of a fluororesin on the surface of the base material.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies on a seamless belt using a low-cost base material, the present inventors have mixed additives such as a plurality of types of fillers in a matrix solvent such as urethane-urea resin, and centrifuged. When molding by adjusting the rotation speed at the time of molding, added fillers etc. are unevenly distributed in the base material, strength, conductivity, it is possible to produce a single-layer endless seamless belt excellent in adhesion,
The inventors have found that by changing the type, size, and amount of the additive, it is possible to impart different properties between the front and back surfaces of the belt, and have obtained the present invention.

Hereinafter, an embodiment of the seamless belt of the present invention will be described.

FIG. 5 is a schematic sectional view showing an embodiment of the seamless belt of the present invention.

In FIG. 5, the base material 4 of the seamless belt is shown.
Reference numeral 1 denotes an elastic material, and the granular first filler 43 is
The surface portion 45 is formed unevenly on the front surface side of the base material 1, and the fibrous second filler 42 is formed unevenly on the back surface side of the base material 41 to form the back surface portion 46.

The first granular filler 43 and the second fibrous filler 42 are unevenly distributed in the base material 41, but are combined with the base material 41 to form a single layer.

On the surface of the seamless belt, a protective layer 44 made of a fluororesin is provided if necessary.

A belt obtained by mixing a plurality of types of fillers having different average shapes in a matrix solvent serving as a base material and centrifugally molding the belt has a difference in bonding strength caused by a difference in a contact area between the base material and the filler. Although it is a single layer, it has different properties such as elasticity and strength between the front and back surfaces.

The mechanical strength can be changed from 2 MPa to 100 MPa by changing the type of base material, the type of filler and the amount of addition.
Degree.

Such a difference in properties between the front and back surfaces of the belt is caused by uneven distribution of additives in the thickness direction of the belt.

A matrix solvent to which a small-sized granular filler and a larger-sized fibrous filler are added is poured into a centrifugal molding machine, and the mixture is rotated at a constant rotation speed to perform centrifugal molding. The filler slips between the fibrous fillers and is unevenly distributed on the inner peripheral surface side of the cylindrical support of the centrifugal molding machine. On the other hand, the fibrous filler is hard to move due to the viscous resistance of the matrix solvent, and is unevenly distributed on the side opposite to the inner peripheral surface side.

Although carbon black and conductive metal oxide are used as the particulate filler, these particulate fillers have almost no effect of reinforcing the base material, and mainly play a role of adjusting the resistance value.

On the other hand, a conductive metal oxide is used as the fibrous filler, but the effect of reinforcing the base material is great because the contact area with the base material is large. By the way, fibrous fillers have a long and short length, and there are thick and thin fibrous fillers.However, fillers with a large contact area with the base material, fillers with long fibers and fillers with a large fiber diameter have a stronger reinforcing effect. growing.

For the base material of the belt, an inexpensive elastic material such as rubber or elastomer is used.

As described above, by using an inexpensive elastic base material and changing the type, size, and amount of the additive, a seamless belt having different properties between the front and back surfaces of the belt can be obtained. Can be used as an endless belt used in the above processes. Furthermore, since it is thin and has elasticity and strength, it can be used as various kinds of transmission belts.

Here, the intermediate transfer belt used in the tandem type full-color printer needs adhesiveness for preventing color misregistration at the time of transfer and strength for circulating and moving by being stretched by a driving roll. By adding a filler in an inexpensive base material and unevenly distributing the same, securing the adhesiveness of the transfer nip portion by the elastic force of the front surface portion 45, and securing the strength by unevenly distributing the fibrous filler on the rear surface portion 46. It can be manufactured at low cost.

In the intermediate transfer belt, the thickness of the surface portion 45 needs to be 5 μm or more and 100 μm or less.

The surface portion 45 is a layer requiring the most elasticity.
If it is too thick, cracks are likely to occur on the surface, and if it is too thin, the function of maintaining elasticity cannot be exhibited. Further, it is difficult to control uneven distribution of the filler, and the filler may be exposed on the surface of the belt.

If the thickness is maintained in this range, the resistance of the deformed portion is temporarily reduced due to the compressive deformation under pressure, and the electrical anisotropy in the thickness direction is formed on the surface of the belt. Can be provided.

Further, the Young's modulus of the surface portion 45 is 10MP.
a.

If the Young's modulus is higher than this, compression deformation in the thickness direction of the belt is less likely to occur when the toner image is transferred to the intermediate transfer belt, so that the adhesion cannot be ensured.

The thickness of the back surface 46 is 50 μm or more,
It needs to be 1 mm or less.

The back portion 46 is a layer for ensuring strength. If the thickness is too small, the required strength cannot be obtained. On the other hand, if the thickness is too large, the rigidity increases, and the shape of the belt when it circulates is increased. In addition to the deterioration of the following ability, there is a possibility that the tension is increased and the elastic limit is exceeded.

Further, the Young's modulus of the back surface portion 46 needs to be 20 MPa or more in order to secure the strength of the entire belt.

Further, it is necessary to adjust the portion close to the surface of the surface portion 45 so as to have the highest resistivity than the volume resistivity of the other portions.

By doing so, it is possible to increase the withstand voltage at the transfer site and to eliminate the unevenness of the resistance. Further, since the surface portion 45 can reduce the amount of filler added for adjusting the resistance, it works advantageously in securing elasticity and adhesion.

It is effective to apply a protective layer 44 made of a fluororesin on the surface of the belt by dip coating or spray coating.

By doing so, the frictional resistance on the surface of the intermediate transfer belt can be reduced, the stability of the electrical characteristics can be ensured, and the releasability of the toner can be improved.

Next, each member used in the embodiment of the seamless belt of the present invention will be described in detail.

First, a urethane resin, a urea resin, or a urethane-urea resin is used as the elastic base material.

From the point of strength, urethane bonds in the molecule,
A urethane-urea resin having (-NHCOO) and a urea bond (-NHCONH-) is desirable.

These are materials that can be adjusted to 9.8-39.2 MPa with a 100% modulus by changing the composition of urea itself, and are suitable as the elastic base material of the seamless belt of the present invention.

The urethane-urea resin is produced by blending at least a catalyst in addition to a polyol, an isocyanate compound and a polyamine compound.

Examples of the polyol include a polyether polyol having a polyhydroxyl group at a terminal and a polyester polyol. Further, a polyol prepolymer obtained by polymerizing an ethylenically unsaturated monomer in a polyol can also be used.

Further, examples of the polyisocyanate compound include various polyols such as toluene diisocyanate, toluene diisocyanate, and isophorone diisocyanate, and prepolymers obtained by reacting with diamines.

However, the elastic substrate may be chlorinated polyethylene, polystyrene-based thermoplastic elastomer, acrylic rubber, or the like.
The material is not limited to the above materials as long as it is an elastic material that can secure a strength of about 20 MPa or more with a% modulus.

Examples of the catalyst include organometallic compounds such as octyl zinc and sodium acetate, alkoxides of alkaline earth metals, phenoxides and Ni acetyl acetate.

Next, various fillers used as additives will be described in detail.

Examples of the granular filler include conductive metal oxides such as conductive carbon black, zinc oxide, potassium titanate, tin oxide, and graphite. In the present embodiment, the influence of the charge history was hardly exerted. Mainly use tin oxide.

Note that tin oxide has high dispersibility in the urethane-urea resin material used as the base material in the present embodiment.

The size is such that the particle diameter in the primary particle state is around 0.2 to 0.7 μm.

The fibrous filler is potassium titanate,
A typical example is aluminum borate, but in the present embodiment, aluminum borate is mainly used.

Here, the shaft diameter is 0.7 μm and the shaft length is about 2
Although the filler having a size of 0 μm is used, the size of the filler can be changed according to the thickness of the belt, a desired Young's modulus, the amount of the filler added, and the like.

In selecting the filler, the wettability between the filler and the substrate is important.

If the wettability between the filler and the substrate is low, a sufficient reinforcing effect cannot be obtained even when the amount of the filler in the substrate is the same.

Here, an example of a method for unevenly distributing the filler in the thickness direction of the belt will be described.

The rearmost side of the rear surface portion 46 (referred to as the lowermost portion)
When the filler having a shaft diameter of 0.7 μm and a shaft length of about 20 μm is unevenly distributed and the Young's modulus near the surface portion 45 is to be lower than that of the filler, the shaft diameter is the same as that of the lowermost one.
Fillers having a length of 7 μm and an axis length of 10 μm or less are added in a reduced amount to about 50% of the fillers unevenly distributed at the lowermost portion, and if molded, these fillers are unevenly distributed near the surface portion 45, The goal can be achieved.

In this case, the temperature and the number of revolutions during molding are important factors, and the outer circumference of the molding apparatus is experimentally 60 to 200
In the case of φ, a rotation speed of about 500 rpm is appropriate. The temperature at the time of molding differs depending on the base material. In the case of the urethane-urea resin mainly used in the present embodiment, about 140 ° C.
Before and after is appropriate.

Next, the protective layer on the surface, which is performed after molding the substrate, will be described.

The material used for the protective layer 44 is not particularly limited as long as it can achieve the purpose of reducing the frictional resistance and improving the cleaning property of the toner by reducing the surface roughness.

Generally, polytetrafluoroethylene,
A paint obtained by dissolving and dispersing a copolymer of tetrafluoroethylene and perfluoroalkylvinyl ether, or a fluororesin polymer in an alcohol-soluble nylon-based or silicone resin-based polymer is used.

The protective layer 44 can be applied by dip coating, spray coating, electrostatic coating, roll coating, or the like, and the film thickness is suitably about 5 μm to 20 μm.

If the coating is too thick, the elasticity of the surface portion 45 is impaired, so that when used as an intermediate transfer belt, the adhesion to the toner image during transfer is reduced.

Next, the resistance required when this seamless belt is used as an intermediate transfer belt will be described.

In FIG. 5, the back surface portion 46 having a high Young's modulus
The 10 ⁵ ~10 ¹³ Ω · Cm, the surface portion 45 is higher than this 10 ⁹ ~10 ¹¹ Ω · Cm, protective layer 44 is 10 ¹² to 10
^The volume resistivity is adjusted to be ¹⁴ Ω · Cm, and the entire elastic base material 41 of the belt is 10 ⁹ to 10 ¹² Ω · Cm. It is necessary to ensure the withstand voltage at the time of applying a high voltage by adjusting the thickness of each part so as to be about the same.

Next, a manufacturing method of the embodiment of the seamless belt of the present invention will be described.

In the seamless belt, a matrix solvent as a base material is mixed with a plurality of fillers having mutually different average shapes, and the solvent is applied to the inner peripheral surface of a cylindrical support of a centrifugal molding machine in which a mold is mounted. Inject, adjust the number of revolutions, and manufacture by centrifugal molding.

[0086] The belt thus manufactured has a single layer and can be made endless, so that an inexpensive belt with a small number of molding steps can be manufactured.

The matrix solvent is prepared by mixing a reactive mixture of a urethane-modified urea resin as a base material at the following mixing ratio.

[Matrix Solvent as Base Material] Teripolyol (molecular weight 5000): 100 parts by weight. Urethane-modified MDI: 18 parts by weight. Hexamethylenediamine: 2 parts by weight. Tetrabutylammonium perchlorate: 0.5 parts by weight. Ketjen Black: 0.2 parts by weight. 1,4 butadieneol.

Then, 10 parts by weight of tin oxide (0.2 μm in primary particles) was added as a particulate filler in the solvent.
m), 1 part by weight of stearic acid, 1 part by weight of a vulcanization accelerator, and 20 parts by weight of aluminum borate (primary particle state, shaft diameter 2 μm, shaft length 7 μm) as a fibrous filler, and the mixed solution was mixed. create.

The above mixed solution is poured into a centrifugal molding machine and baked at a molding temperature of 140 ° C. for about 15 minutes. At this time, if the rotation speed of the centrifugal molding machine is too high, all the fillers are unevenly distributed on the inner peripheral surface side of the centrifugal molding machine. Therefore, when the outer circumference of the apparatus is about 60 to 200φ, 500 rpm or 1000 rpm. Must be about .pm.

As a result, small-sized granular fillers are unevenly distributed on the front surface portion 45, and larger fibrous fillers are unevenly distributed on the back surface portion 46.

A belt diameter of 168φ, a thickness of 150 μm, and a width of 330 mm were formed at a centrifugal molding speed of 500 rpm.
In the case of the belt of No. 1, tin oxide was dispersed from the front surface to a thickness of about 30 μm, and the fibrous filler was unevenly distributed over the back surface side over the thickness of 100 μm.

Next, if necessary, a protective layer 4 is formed on the belt surface.
4 is applied.

This step is a step performed when the surface properties and surface resistance of the belt are independently adjusted, and is not necessary for all belts.

Here, JLY-841B (manufactured by Nippon Acheson Co., Ltd.) composed of a urethane-modified emulsion paint containing a tetrafluoroethylene resin (PTFE) and a silane coupling agent as a curing agent was applied to the above molded belt. The paint is applied by, for example, an electrostatic coating method to form a conductive protective layer having a thickness of 5 μm.

Incidentally, the electric resistance is 10 ^11.5 Ω · Cm including the base material when DC 500 V is applied.

Next, an embodiment of the image forming apparatus of the present invention will be described.

FIG. 6 is a schematic configuration diagram showing an embodiment of the image forming apparatus of the present invention.

In FIG. 6, a drive control board 1 controls the entire image forming apparatus, and a scanner 2 controls the drive control board 1.
And emits a laser beam corresponding to the image signal based on the instruction. The photoconductor 3 is charged by being supplied with a charge from a charging device (not shown), and receives a laser beam from the laser exposure device 2 to form a latent image based on an image signal. The latent image is developed by the developing device 4 to become a toner image, and is transferred to the intermediate transfer belt 6 by the transfer electric field of the primary transfer roll 5.

Here, in the present embodiment, the seamless belt of the embodiment of the present invention is used as the intermediate transfer belt.

The intermediate transfer belt 6 is circulated in the direction A by the transport roll 12, and the toner image on the photoreceptor 3 is transferred to the intermediate transfer belt 6 in the order of yellow, magenta, cyan, and black. The intermediate transfer belt 6 onto which these toner images have been transferred sandwiches a sheet (not shown) conveyed by a roll (not shown) between the intermediate transfer belt 6 and a secondary transfer roll 7, and transfers the transfer electric field of the secondary transfer roll 7. , These toner images are collectively transferred to paper. The sheet 8 onto which the toner image has been transferred is fixed by the fixing roll 9 under the pressure of the pressure roll 11.

On the other hand, the residual toner on the intermediate transfer belt 6 is collected by the cleaner 10 and is returned to the developing step.

The seamless belt in which metal oxide such as tin oxide is unevenly distributed on the surface as the granular filler 43 shown in FIG. 5 is different from the one in which carbon black is unevenly distributed, and the electric charge is accumulated on the belt itself. Is not generally provided in an intermediate transfer type image forming apparatus,
The intermediate transfer belt cleaner 10 can be omitted.

When a belt provided with a protective layer 44 by applying a fluororesin or the like on the surface is used, the releasability of the toner is improved, which is effective in improving so-called hollow holes.

As described above, the seamless belt according to the embodiment of the present invention satisfies strength, adhesion, and predetermined conductivity, and is low in cost. be able to.

In addition to the image forming apparatus described in this embodiment, the image forming apparatus carries a recording medium on its surface and transports the toner image formed on the image carrier to a transfer position where the toner image is transferred to the recording medium. There is an image forming apparatus using a conveyor belt,
The seamless belt of the present invention can be used as the paper transport belt.

In the present embodiment, a roll-type fixing device is used. However, an image forming method using a fixing belt that contacts a recording medium on which a toner image has been transferred on its surface and fixes the toner image on the recording medium is used. There is an apparatus, and the seamless belt of the present invention can be used as the fixing belt.

Further, although a charging device (not shown) is used in the present embodiment, there is an image forming apparatus which uses a charging belt which is supported so as to be in contact with the image carrier and charges the image carrier. The seamless belt of the present invention can be used as the charging belt.

[0109]

EXAMPLES (Example 1) The following experiment was performed to confirm the mechanical strength of the belt and the transfer performance of a toner image when the seamless belt of the present invention was used as an intermediate transfer belt.

The schematic configuration diagram of the image forming apparatus used in the experiment is the same as the schematic configuration diagram shown in FIG. 6, the description thereof is omitted, and the specific configuration conditions are shown below.

The sectional configuration of the seamless belt used for the intermediate transfer belt is the same as the schematic configuration shown in FIG. 5, and the description thereof is omitted, and only specific configuration conditions are shown.

The experimental results shown below as this embodiment and other examples and comparative examples are based on the results of color shift during transfer, strength at 100% modulus, dielectric strength (presence or absence of leak when 1000 V is applied). Are summarized in Table 1.

Photoconductor: OPC photosensitive material. Process speed: 80 mm / s Developer carrier; 15 mm aluminum hollow pipe subjected to alumite treatment (Surface roughness Ra: 1.0) Toner layer forming member; 0.5 mm thick SUS plate with rubber hardness Transfer device; foamed silicone rubber compounded with ionic conductor, φ20 volume resistivity of 10 ⁸ Ω.Cm Latent image potential; -100 V background portion; -350 V intermediate transfer belt; belt formed by centrifugal molding of a mixture of the following base materials and a filler base material: 100 parts by weight of teribolol (molecular weight 5000) (manufactured by Asahi Glass Co., Ltd.) 18 parts by weight of urethane-modified MDI (Sumitomo) Hexamethylenediamine 2 parts by weight Tetrabutylammonium perchlorate 0.5 parts by weight Ketjen black 0.2 parts by weight 1,4 Butadieneol Filler: 10 parts by weight of tin oxide (manufactured by Kasei Kasei Kogyo) Aluminum borate (primary particle state, shaft diameter 2 μm, shaft length μm,) 20 parts by weight (Mitsui Metals) Rib: Simultaneous fusion in the mold during secondary firing. Firing temperature 140 ° C. Number of revolutions during centrifugal molding; 500 rpm Film thickness; 150 μm Outer diameter; 168 φ width; 330 mm Surface resistance of belt; 10 ¹¹ Ω / □ Volume resistance; 10 ⁸ Ω.Cm Fixing device: Uses a # 40 hollow pipe using 0.5 mm thick SUS material Heat lamp: Tungsten lamp rated at 650 Pressure roll; Used by covering SUS330φ cylinder with 50 μm thick rubber layer A DC bias voltage of 500 V is applied to the shaft. Cooling fan; use a long electric fan Paper; J paper (manufactured by Fuji Xerox Co., Ltd.)

The intermediate transfer belt thus formed has a mechanical strength of 100% modulus of 39.2 MPa.
The hybrid belt had a surface hardness of JIS-A hardness of 20 degrees or less. Even when the belt was rotated at the above-mentioned process speed with the belt tension of 49 N, the color shift at the time of transfer could be suppressed to 100 μm or less. In addition, a good image was obtained without toner scattering.

(Example 2) Among the specific constituent conditions set in Example 1, the fibrous filler added to the substrate was changed to potassium titanate, and the fibrous filler was changed to 15 μm.
m length.

By doing so, the strength of the belt is improved, it becomes 49 MPa at a 100% modulus, and the hardness of the surface portion can be made 20 degrees or less in JIS-A hardness while securing the rigidity of the belt. Was.

Further, even if the process speed of rotating the belt was increased to about twice that of the first embodiment, no problem occurred in the belt itself, and a high-quality color image without color shift was stably obtained. . At this time, R paper (manufactured by Fuji Xerox Co., Ltd.) was used.

Example 3 Of the specific structural conditions set in Example 1, the main raw material of the elastic base material was changed to polyester polyol, and the particulate filler unevenly distributed on the surface portion was made of titania and tin oxide. The molding was carried out by changing to 5 parts by weight. In addition, the transfer roll was changed to a metal roll for cost reduction.

Under the above constitutional conditions, since the filler content is not increased, the influence on the mechanical elasticity is small, and the resistance of the surface where the granular filler is unevenly distributed can be easily adjusted. We were able to. The surface resistance at this time was 10 ¹² Ω / □. Here, R paper (manufactured by Fuji Xerox Co., Ltd.) was used as the paper, and a high-quality color image was stably obtained at high speed.

(Example 4) [0120] Of the specific constitutional conditions set in Example 1, the addition amount of the fibrous filler was reduced to 15 parts by weight.

When molded under these conditions, the thickness in which the fibrous filler was dispersed was 80 μm, and the thickness in which the particulate filler tin oxide was dispersed was 60 μm.

Under these conditions, since the thickness of the elastic portion in which tin oxide is dispersed increases, the adhesion at the time of transfer can be further secured, and in particular, the transferability of isolated particles in the highlight portion is improved.

(Embodiment 5) Under the same conditions as those of Embodiment 3,
Fluoropolymer PVD on the surface of the intermediate transfer belt
F was dip-coated to obtain a protective layer having a thickness of about 10 μm.

As described above, by applying a material from which the toner is easily released to the surface, the residual toner on the belt can be easily collected, and a high-quality color image can be stably obtained.

(Comparative Example 1) When the molding speed of the intermediate transfer belt was set to 2000 rpm under the same configuration conditions as in Example 1, all of the added particulate filler and fibrous filler were all on the mold side of the centrifugal molding machine. And the surface portion was hard, and the 100% modulus was 29.4 MPa. In addition, a part of the filler was exposed on the belt surface, and the surface property could not be secured.

Comparative Example 2 Under the same constitutional conditions as in Example 1, 30 parts by weight of tin oxide having a particle diameter of about 0.7 μm was added instead of the fibrous filler.

In the belt prepared under these conditions, although the filler was uniformly dispersed in the belt thickness direction, the mechanical strength was hardly changed, and the 100% modulus was about 9.8 MPa. Further, since the particles were uniformly dispersed in the thickness direction, an elastic layer could not be formed on the surface.

Comparative Example 3 Under the same configuration conditions as in Example 1, the amount of the filler unevenly distributed on the surface portion was reduced from 10 parts by weight to 5 parts by weight, and the rotation speed of the centrifugal molding machine was set at 800 rpm.
raised to m.

When this condition is changed, the amount of the filler unevenly distributed on the surface portion is small, and since the centrifugal force is strong, the filler is unevenly distributed only at 5 μm or less from the surface, and the elastic force is JIS-A hardness of 40. The required elastic force was not able to be developed because of the degree.

(Comparative Example 4) Under the same constitutional conditions as in Example 1, the amount of the fibrous filler was reduced to 5 parts by weight, and the molding speed was reduced to 300 rpm to perform molding.

In the belt molded under these conditions, the fibrous filler was dispersed with a thickness of 50 μm on the back surface, and tin oxide as a particulate filler was dispersed on the front surface with a thickness of 90 μm. In this case, since the thickness of the elastic portion became about 90 μm, some cracks occurred.

[0132]

[Table 1]

[0133]

As described above, according to the present invention, a low-cost seamless belt composed of a single layer can be provided by using a low-cost elastic member. In addition, the strength and adhesion of the seamless belt can be arbitrarily changed by changing the type and amount of the additive to be added to the elastic member. In addition, the manufacturing method can be formed into an endless belt shape by a single forming step without going through a plurality of steps leading to an increase in cost. Furthermore, if this seamless belt is used in each process of the image forming apparatus, it is possible to provide an image forming apparatus capable of obtaining a high-quality color image at low cost. In particular, when used as an intermediate transfer belt, it is possible to stably provide a high-quality color image with almost no toner scattering or color shift.

[Brief description of the drawings]

FIG. 1 is a schematic sectional configuration diagram of a conductive seamless belt shown as a conventional example.

FIG. 2 is a schematic sectional configuration diagram of an endless belt shown as a conventional example.

FIG. 3 is a schematic sectional configuration diagram of an intermediate transfer belt shown as a conventional example.

FIG. 4 is a schematic perspective view of a reinforcing fiber member shown enlarged as an example.

FIG. 5 is a schematic sectional configuration diagram showing an embodiment of a seamless belt of the present invention.

FIG. 6 is a schematic configuration diagram illustrating an embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control board 2 laser exposure device 3 photoreceptor 4 developing device 5 primary transfer roll 6 intermediate transfer belt 7 secondary transfer roll 8 paper 9 fixing roll 10 cleaner 11 pressure roll 12 transport roll 30 surface layer 31 intermediate layer 32 inner layer 33 coating Membrane 34 Reinforcement film 35, 36 Elastic layer 37 Reinforcing fiber member 38 Woven cloth 41 Base material 42 Fibrous second filler 43 Granular first filler 44 Protective layer 45 Front surface 46 Back surface

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08K 7/02 C08K 7/02 9/00 9/00 C08L 101/00 C08L 101/00 G03G 15/16 G03G 15/16 // B29K 75:00 B29K 75:00 105: 16 105: 16 B29L 29:00 B29L 29:00 (72) Inventor Kazuhiro Hayashi 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Office (72) Inventor Jin Iwasaki 2274 Hongo, Ebina-shi, Kanagawa Prefecture F-Terminus in Ebina Office of Fuji Xerox Co., Ltd.F-term (reference) AF39 AH12 AH16 AH17 BC01 4F205 AA16 AA31 AB11 AB16 AB17 AB18 AB25 AC05 AG16 AR09 GA01 GB01 GC04 GE02 GE22 GF01 GF21 GF27 GN01 GN13 GN24 4J002 CC161 CK021 DA026 DA036 DE016 DE017 DE096 DE136 DE186 DE47FA DK00 FA

Claims (21)

[Claims] 1. A seamless belt comprising a base material having a single layer having different properties on a front surface and a back surface due to uneven distribution of an additive in a thickness direction. 2. The seamless belt according to claim 1, wherein said additive comprises a mixture of plural kinds of fillers having different average shapes. 3. The method according to claim 1, wherein the additive is a particulate first filler,
The seamless belt according to claim 1, further comprising a fibrous second filler. 4. The seamless belt according to claim 1, wherein the first filler is relatively unevenly distributed on the front side and the second filler is unevenly distributed on the rear side. 5. The seamless belt according to claim 1, wherein said base material is an elastic material. 6. The seamless belt according to claim 1, further comprising a protective layer made of a fluororesin on the surface. 7. The seamless belt according to claim 3, wherein said first filler is made of carbon black or a conductive metal oxide. 8. The seamless belt according to claim 3, wherein said second filler is made of a conductive metal oxide. 9. The seat belt according to claim 4, wherein a thickness of a portion where the first filler is unevenly distributed in the base material is 5 μm or more and 100 μm or less. 10. The seat belt according to claim 4, wherein a thickness of a portion of the base material where the second filler is unevenly distributed is 50 μm or more and 1 mm or less. 11. The seat belt according to claim 4, wherein a Young's modulus of a portion where the first filler is unevenly distributed is 10 MPa or less. 12. The seat belt according to claim 4, wherein a Young's modulus of a portion where the second filler is unevenly distributed is 20 MPa or more. 13. The seamless belt according to claim 4, wherein a portion close to the surface of the base material has a highest volume resistivity than other portions. 14. The seamless belt according to claim 8, wherein the second filler is conductive-treated potassium titanate or conductive-processed aluminum borate. 15. A method for producing a seamless belt having a base material comprising a single layer, wherein the additive is mixed in a matrix solvent, and the single layer having different properties between the front surface and the back surface due to uneven distribution in the thickness direction by centrifugal molding. A method for producing a seamless belt, comprising forming a substrate comprising: 16. The method for producing a seamless belt according to claim 15, wherein a plurality of types of fillers having different average shapes are mixed in said matrix solvent and centrifuged. 17. The method for producing a seamless belt after centrifugal molding so that the base material constituting the seamless belt forms a single layer having different properties on the front surface and the back surface due to uneven distribution of the additive in the thickness direction. The method for producing a seamless belt according to claim 15, wherein the number of rotations of the seamless belt is adjusted. 18. A matrix solvent mixed with additives is injected into the inner peripheral surface of a cylindrical support of a centrifugal molding machine so that the seamless belt after being manufactured as a seamless belt has an endless belt shape. The method for producing a seamless belt according to claim 15, wherein the seamless belt is formed by centrifugal molding. 19. An image comprising a fixed toner image is formed on a recording medium by forming a toner image on an image carrier and finally transferring and fixing the toner image on a predetermined recording medium. In an image forming apparatus, a seamless belt is used in any process of image formation, and the seamless belt has a base material including a single layer having different properties between a front surface and a back surface due to uneven distribution of an additive in a thickness direction. An image forming apparatus comprising: 20. Intermediate transfer wherein said seamless belt receives a transfer of a toner image formed on said image carrier, and conveys the toner image to a secondary transfer device for secondary transfer to a predetermined recording medium. The belt is a belt.
The image forming apparatus as described in the above. 21. Forming a toner image on a recording medium by forming a toner image on an image carrier, and finally transferring and fixing the toner image on a predetermined recording medium. An image forming apparatus, comprising: an intermediate transfer belt that receives a transfer of the toner image formed on the image carrier, and conveys the toner image to a secondary transfer device that performs secondary transfer on a predetermined recording medium. The intermediate transfer belt has a base material consisting of a single layer having different properties on the front surface and the back surface due to uneven distribution of the additive in the thickness direction and a seamless belt having a protective layer made of a fluororesin on the surface of the base material. An image forming apparatus, comprising: