JP2000003100A - Belt for image forming device, and intermediate transfer belt, transfer material carrying belt, transfer belt and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer belt, a transfer material carrying belt, a transfer belt and a transfer device and an image forming device using them which are constituted so that the deformation of the belt is reduced, a resist deviation is hardly caused, a middle omission of image is prevented and reduction of the cost is realized. SOLUTION: This belt B for image forming device used in an image forming device F in which an electrostatic latent image formed on an image carrier 16 is developed to be a toner image and the toner image is transferred to transfer material S is provided with a base layer B1 and a surface layer B2 laminated on the surface side of the base layer B1, and the back surface side of the base layer B1 is rotatably supported by belt supporting members 25 to 29. The tensile elastic modulus of the base layer B1 is <=10,000 kg/cm2 and that of the surface layer B2 is >=15,000 kg/cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic belt-shaped member used in a black-and-white and full-color image forming apparatus using an electrophotographic method, such as a copying machine, a printer, and a facsimile. Particularly, the toner image formed on the image carrier is transferred to a transfer material (plain paper, high-quality paper, printing paper, postcard, envelope, O
The present invention relates to a belt-shaped transfer member for transferring to an HP film or the like and an image forming apparatus using the same. More specifically, a belt-shaped intermediate transfer member that carries a toner image formed on the surface of an image carrier by a primary transfer unit and transfers the toner image to a transfer material surface by a secondary transfer unit, The transfer material is conveyed while electrostatically attracting, and a transfer bias is applied to the belt-shaped transfer / transport member, which forms a toner image on the transfer material. The present invention relates to a belt-shaped transfer member for applying a charge to the back surface of a material and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Toner images formed on the surface of an image carrier are
A belt-like intermediate transfer member that is carried on the surface by the next transfer means and transfers the toner image to the surface of the transfer material by the secondary transfer means; the transfer material is conveyed while electrostatically attracting the transfer material; A belt-shaped transfer / conveying member for forming a toner image thereon, a belt-shaped transfer member for passing a transfer material between the transfer member and an image carrier, and applying a transfer bias to apply a charge to the back surface of the transfer material, and these were used. 2. Description of the Related Art Image forming apparatuses have been widely used in electrophotographic apparatuses in recent years.

The structure of these belt-shaped transfer members is roughly classified into the following three types. (1) A material having a high Young's modulus (tensile elastic modulus) is used as a single-layer belt, and is made of PC (polycarbonate, JP-A-6-95521) and PVDF (polyvinylidene fluoride, JP-A-5-200904). , Japanese Unexamined Patent Publication No.
228335), PAT (polyalkylene terephthalate, JP-A-6-149081), PC (polycarbonate) / PAT (polyalkylene terephthalate) blend material (JP-A-6-149083) ETFE (ethylene tetrafluoroethylene copolymer) Polymer) / PC, ETFE / PAT, PC / PAT blend material (JP-A-6-149079), carbon black-dispersed thermosetting polyimide (JP-A-63-311)
No. 263) has been proposed. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation due to the stress during image formation is small, and particularly, the resist is not easily shifted during color image formation.

(2) A belt having a high Young's modulus is used as a base layer, and a surface layer or an intermediate layer is provided on the outer periphery of the base layer.
The belt has a three-layer structure, and Japanese Patent Application Laid-Open No. 9-244427 and the like have been proposed. These two- to three-layer belts have a performance capable of preventing the dropout of a line image caused by the hardness of the single-layer belt.

(3) A belt having a relatively low Young's modulus using rubber and an elastomer.
No. 57, JP-A-8-160766, JP-A-9
-269678, and the like. These belts have an advantage in that the softness of the belt hardly causes a drop in the line image. Also, Japanese Patent Application Laid-Open No. 8-301
As disclosed in JP-A-21, the width of the belt is made larger than that of the drive roll and the tension roll, and meandering is prevented by utilizing the elasticity of the belt ears protruding from the roll. Can be realized.

[0006]

However, the above-mentioned various belts have the following problems. (1) In a single-layer belt having a high Young's modulus, since the elastic deformation of the belt is small with respect to the pressing force of the bias roller at the transfer portion, the pressing force is concentrated on the toner layer, and the toner is aggregated and the line image is lost. Is easy to occur. In addition, when the belt has a small thickness unevenness or circumferential deviation, the outer diameter of the drive roll or the tension roll is slightly distorted, and the frame on which these are attached has a slight distortion, the belt having a high Young's modulus has little elastic deformation. So it will meander. Therefore, in order to use a belt having a high Young's modulus, Japanese Unexamined Patent Publication No. Hei.
As disclosed in Japanese Patent Application Laid-Open No. 9-165120 and Japanese Patent Application Laid-Open No. 9-165120, a belt is required to have a meandering prevention rib, and a meandering prevention guide device and the like are required, resulting in an increase in cost.

(2) A belt having a high Young's modulus is used as a base layer,
In a belt having a two- or three-layer structure in which a surface layer or an intermediate layer is provided on the outer periphery, the amount of deformation of the surface layer cannot follow the amount of deformation of the base layer or the intermediate layer, causing cracks or insufficient adhesion to the base layer. As a result, the surface layer or the intermediate layer may be peeled off, resulting in an image defect. In addition, the provision of the surface layer or the surface layer and the intermediate layer complicates the manufacturing process and raises the cost. In addition, since the base layer has a high Young's modulus, it tends to meander as in the previous section. Therefore, a rib and a meandering prevention device are required, and a cost increase from this point cannot be avoided.

(3) A belt using a rubber and an elastomer having a relatively low Young's modulus is liable to cause misregistration due to elongation. In order to prevent belt elongation, the actual opening was 3-69166.
JP, JP-A-3-293385, JP-A-9-1
Japanese Patent Application Laid-Open No. 90090, Japanese Patent Application Laid-Open No. 9-251246, and the like have proposed a belt in which fibers and a core material are combined. In some cases, density unevenness due to a difference in electrical resistance between the image and the image may appear in an image. In addition, since the fibers and the core material are combined with the matrix component, the manufacturing process is complicated and the cost is unavoidable.

[0009] In view of the above problems, the present invention has the following content (O01). (O01) According to the present invention, belt deformation due to stress at the time of driving is small and registration is unlikely to occur, and toner agglomeration due to concentration of pressing force by a bias roller at a transfer section is reduced to prevent image dropout. Further, the present invention provides an intermediate transfer belt, a transfer material conveying belt, a transfer belt, and a transfer device and an image forming apparatus using the same, which do not require a rib or a meandering prevention device for preventing belt meandering, thereby realizing low cost. Is what you do.

[0010]

Next, the present invention devised to solve the above-mentioned problems will be described. The elements of the present invention can be easily associated with the elements of the embodiments or modifications described later. In this case, the reference numerals of the elements of the embodiment or the modified example are enclosed in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the following embodiments or modified examples is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the examples.

(First Invention) A belt (B) for an image forming apparatus according to the first invention comprises an image carrier (16, 56k to 56c, 6).
1) A belt (B) used in an image forming apparatus (F) in which an electrostatic latent image formed thereon is developed into a toner image and the toner image is transferred to a transfer material (S), and the belt (B) includes a base layer ( B
1) and a surface layer (B2) laminated on the front side of the base layer (B1), and the back side of the base layer (B1) can be rotated by the belt support members (25 to 29, 51 to 54, 66 to 67). In the belt (B) for an image forming apparatus supported by the above, the tensile elastic modulus of the base layer (B1) is 10,000 k
g / cm ² or less, and the tensile modulus of the surface layer (B2) is 15000 kg / cm ² or more.

(Operation of the First Invention)
In the belt (B) for an image forming apparatus of the present invention, the tensile modulus is a value obtained by the following equation (1) in accordance with JIS K-7127. Em = △ σ / △ ε (1) where Em: Tensile modulus (N / mm ² ) Δσ: Straight line The difference in stress due to the original average cross-sectional area between two points (N / mm ² ) Δε: Determined as the difference in strain between the same two points.

That is, the first invention provides a plurality of belt support members (25 to 29, 51 to 5) for supporting the belt (B).
4, 66 to 67), and a belt (B) for an image forming apparatus comprising at least two layers of a base layer (B1) supported by a surface layer (B2), and each layer is separated in function as follows. ing. First, the base layer (B1) has a tensile modulus of 1
By controlling the pressure to 0000 kg / cm ² or less, load fluctuation (stress) generated during belt driving is absorbed to prevent meandering. Here, the tensile modulus of the base layer (B1) is 10,000 kg / cm ²
If the ratio exceeds the above range, the elastic deformation of the base layer (B1) becomes difficult to occur, so that the stress at the time of driving the belt cannot be absorbed, and the meandering is likely to occur. Further, since the elastic deformation of the belt (B) is reduced with respect to the pressing force of the bias roller at the transfer portion, the pressing force is concentrated on the toner layer, the toner is aggregated, and the line image is apt to drop out. . The lower limit of the tensile modulus of the base layer (B1) is not particularly limited, but is preferably 500 kg / cm ² or more, more preferably 1000 kg / cm ² or more.
If the tensile modulus of the base layer (B1) is less than 500 kg / cm ² , the deformation of the base layer (B1) due to the stress at the time of driving the belt increases, and the surface of the belt (B) tends to undulate or undulate.

Further, the thickness of the base layer (B1) is 10 mm or less, preferably 5 mm or less. Too base layer (B
When 1) is thick, a large speed difference is generated between the inner circumference and the outer circumference of the belt (B) at the stretch roll portion, so that the registration is likely to occur. The material used for the base layer (B1) is preferably a rubber or an elastomer. Specifically, natural rubber and isoprene, butadiene, styrene, styrene / butadiene, butyl, ethylene / propylene, hypalone, epichlorohydrin, nitrile, acrylic, urethane, thiochol, Rubbers represented by silicon, fluorine and the like, and elastomers composed of these, in addition, elastomers composed of polyester, polyamide, polyvinyl chloride, polyvinyl ether, polyurea and the like, and mixtures or copolymers composed of two or more of these may be mentioned. it can. To these materials, conductive or semiconductive pigments such as carbon black, acetylene black, graphite, metal oxides, composite metal oxides, metal powders, and ionic conductive agents such as perchlorates or quaternary ammonium salts are added. These are used alone or in combination of two or more to adjust the electric resistance.

On the other hand, the surface layer (B2) has a tensile modulus of 150
By setting the pressure to 00 kg / cm ² or more, the elongation of the belt (B) is suppressed, and the misregistration is prevented. When the tensile modulus of the surface layer (B2) is less than 15,000 kg / cm ² , the resistance (strength) against load fluctuation (stress) during belt driving is low, and the belt (B) elongates, and it is not possible to prevent the displacement. Here, the relationship between the tensile modulus of the belt material and the amount of displacement (elongation) of the belt (B) due to load fluctuation (stress) during belt driving is shown in equation (2). Δl = P · l · α / (t · w · E) ················································ (2) where Δl: displacement amount (μm) of belt (B) : Load (N) l: Length of belt (B) between two tension rolls (mm) α: Coefficient t: Belt thickness (mm) w: Belt width (mm) E: Tensile modulus of belt material ( N / mm ² ).

From the equation (2), the amount of displacement of the belt (B) due to the load fluctuation at the time of driving the belt is inversely proportional to the tensile elastic modulus of the belt material. It is clear that the amount of displacement of the belt (B) can be kept small, and the present inventor sets the tensile elastic modulus of the surface layer material to 15,000 kg / cm ² or more when combined with the base layer (B1) described in the preceding section. It has been found out that the displacement (elongation) of the belt (B) can be suppressed to prevent the misregistration. The upper limit of the tensile modulus of the surface layer (B2) is not particularly set, but generally, as the tensile modulus increases, the toughness is lost and the material becomes very brittle. Therefore, the surface layer (B
The upper limit of the tensile modulus in 2) is desirably 100,000 kg / cm ² or less, preferably 80,000 kg / cm ² or less.

The thickness of the surface layer (B2) is 10 mm or less, preferably 5 mm or less. Too surface layer (B
When the thickness of the belt (B) becomes thicker, a large speed difference is generated between the inner circumference and the outer circumference of the belt (B) at the tension roll portion, so that the registration is liable to occur. Because elastic deformation is reduced,
The pressing force is concentrated on the toner layer, and the toner is aggregated, so that the line image is likely to have a void. Materials used for the surface layer (B2) include polyethylene, polypropylene, polystyrene, polyisobutylene, polyester, polyurethane, polyamide, polyimide, polyamideimide, alcohol-soluble nylon, polycarbonate, polyarylate, phenol, polyoxymethylene, polyetheretherketone, and polyetheretherketone. Phosphazene, polysulfone, polyether sulfide, polyphenylene oxide, polyphenylene ether, polyparabanic acid, polyallylphenol, polybenzimidazole, urea,
Examples thereof include thermoplastic resins and thermosetting resins such as fluorine, polyurea, ionomer, and silicone, and mixtures or copolymers of two or more of these.
Similarly to the base layer (B1), the surface layer (B2) is a conductive or semiconductive pigment such as carbon black, acetylene black, graphite, a metal oxide, a composite metal oxide, or a metal powder, and further is a perchlorate or quaternary ammonium. An ion conductive agent such as a salt may be used alone or in combination of two or more to adjust electric resistance.

Here, the electric resistance of the belt (B) will be described. The electrophotographic belt (B) according to the present invention has a surface resistivity of 8.0 Log Ω / □ to 15.0 Log Ω / □ and a volume resistivity of 6.0 Log Ωcm to 13.
It is necessary to keep it within 0 LogΩcm. 7. Surface resistivity is 8.
If it is less than 0 LogΩ / □, the applied charge is removed due to the conductivity of the belt itself, and the electrostatic force for transferring the toner image does not work. As a result, when the belt (B) is used as an intermediate transfer belt, the image carrier (16, 5
6k to 56c, 61), the electrostatic force holding the electric charge of the unfixed toner image transferred to the intermediate transfer belt stops working, and the electrostatic repulsive force between the toners and the force of the fringe electric field near the image edge are stopped. This causes a problem that toner scatters around the image and an image with large noise is formed. In particular, this phenomenon appears remarkably around an image having a large amount of toner per unit area, such as a multi-transferred image, which is a fatal defect for a color image forming apparatus. Conversely, if the surface resistivity exceeds 15.0 Log Ω / □, electric charges are likely to be accumulated, and a problem arises in that a charge eliminating mechanism is required, leading to an increase in cost.

Since the surface resistivity is dominant in the surface resistivity,
The surface resistivity of the resin material itself forming the surface layer is 8.0 L
It needs to be adjusted in the range of ΩΩ / □ to 15.0 LogΩ / □. On the other hand, the resistance of the base layer (B1) needs to be adjusted within a range that does not affect the surface resistivity of the surface layer.
It is sufficient if the surface resistivity is suppressed to be equal to or less than the surface resistivity of the surface layer. The volume resistivity is from 6.0 LogΩcm to 13.0 Lo from the correlation between the surface resistivity and the volume resistivity in the standard environment (22 ° C., 55%) shown in FIG.
It is preferable to be within the range of gΩcm.

The measurement of the surface resistivity and the volume resistivity referred to here is performed by using a Hirester IP resistance meter and an HR probe (both manufactured by Mitsubishi Yuka) based on the measured values at an applied voltage of 100 V and an applied time of 30 seconds. This is a value obtained by using Expressions (3) and (4). ρs = Log10 (Rs × 10) (3) where ρs = surface resistivity (LogΩ / □) and Rs = actual measured surface resistance (Ω). ρv = Log10 (S × Rv / t) (4) where ρv = volume resistivity (LogΩcm) S = cross-sectional area of HR probe (cm ² ) Rv = Measured value of volume resistance (Ω) t = thickness (cm)

As described above, the surface layer (B2) that controls the surface resistance of the belt (B) needs to have its resistance range strictly adjusted, but the base layer (B1) has an influence on the electric resistance of the surface layer (B2). It is enough if the adjustment is made within the range not given. The following methods can be used for the method of producing the belt (B). (1) The base layer (B1) and the surface layer (B2) are separately prepared, and both are bonded using an adhesive such as epoxy, urethane, polyester, silicon, acryl, cyanoacrylate or double-sided tape, and then the ends are joined. . Note that an adhesive or a double-sided tape in which carbon or metal powder is dispersed to impart conductivity may be used. (2) After the base layer (B1) and the surface layer (B2) are simultaneously molded by co-extrusion, the ends are bonded together. (3) The surface layer (B2) is heated and adhered while passing the unvulcanized rubber through a calender roll. (4) After forming the surface layer (B2) as an endless belt by centrifugal molding, the base layer (B1) is poured into the inner surface of the belt and molded. Alternatively, the surface layer (B2) is formed into an endless belt by centrifugal molding, and then bonded. In addition, the said manufacturing method is an example and is not limited to this.

(Second Invention) A belt (B) for an image forming apparatus according to a second invention of the present invention comprises an image carrier (16, 56k to 5).
6c, 61) is a belt (B) used in an image forming apparatus in which the electrostatic latent image formed on the toner image is developed into a toner image and the toner image is transferred to a transfer material (S). )
And a surface layer (B) laminated on the surface side of the base layer (B1).
2) The belt (B) for an image forming apparatus, wherein the back side of the base layer (B1) is rotatably supported by the belt support members (25 to 29, 51 to 54, 66 to 67). The hardness of (B1) is 90 or less in JIS-A hardness, and the hardness of the surface layer (B2) is AS
It is characterized by being 60 or more in TMD-785.

(Operation of the Second Invention)
In the belt (B) for an image forming apparatus according to the present invention, the base layer (B1) absorbs load fluctuation (stress) generated during belt driving to prevent meandering, and reduces the pressing force of the bias roller at the transfer portion by elastic deformation. Since it functions to reduce and prevent hollowing out, a certain degree of softness is required.
As a result of intensive studies, the inventor has found that the upper limit is JIS-A
A conclusion was reached that the hardness was 95 degrees. Base layer (B
If the hardness of 1) exceeds 95 degrees, it is too hard.
Elastic deformation is less likely to occur due to load fluctuation (stress) generated at the time of driving the belt and pressing force at the transfer portion, and meandering and hollowing out are more likely to occur. The lower limit of the hardness of the base layer (B1) is JIS-
The hardness A is 30 degrees, and if it is less than 30 degrees, the elastic deformation is large and the belt (B) surface is likely to undulate or wrinkle.

On the other hand, the hardness of the surface layer (B2) is ASTM D-
In 785, it is 60 or more, preferably 80 or more.
If the hardness of the surface layer (B2) is less than 60, the nip with the photoconductor is difficult to be uniform, and the surface layer (B2)
Are easily deformed (submerge too much), so that problems such as a decrease in transfer efficiency and deterioration of hollowing out easily occur. Although there is no particular upper limit for the surface layer (B2) hardness, it is generally AST.
It is 150 in MD-785. If the hardness of the surface layer (B2) is too high, even if the base layer (B1) is elastically deformed, the effect is not exerted, and the base layer (B1) does not exhibit its effect, or the surface layer (B2)
2) The toner may be fused. The material, thickness, electric resistance range, manufacturing method, and the like of each layer used in the second invention are the same as those in the first embodiment.
Same as the invention.

(Third Invention) A belt (B) for an image forming apparatus according to a third invention is an image bearing member (16, 56k to 56c, 6).
1) A belt (B) used in an image forming apparatus in which an electrostatic latent image formed thereon is developed into a toner image and the toner image is transferred to a transfer material (S), and includes a base layer (B1) and A surface layer (B2) laminated on the front side of the base layer (B1), and the back side of the base layer (B1) is provided on the belt support member (25).
To 29, 51 to 54, 66 to 67), the base layer (B1) is a foam, and the surface layer (B2) is a film. There is a feature.

(Operation of the Third Invention) In the belt (B) for an image forming apparatus having the above-described configuration, the base layer (B1) can always be elastically deformed by a constant amount with respect to the tension when the belt is driven. , A foam is used. The material used for the base layer (B1) is a foam made of rubber or an elastomer. Specifically, natural rubber and isoprene, butadiene, styrene, styrene / butadiene, butyl, ethylene / propylene, hypalone, epichlorohydrin,
Rubbers represented by nitriles, acrylics, urethanes, thiocols, silicones, fluorines, etc., and elastomers composed of these, in addition, elastomers composed of polyester, polyamide, polyvinyl chloride, polyvinyl ether, polyurea, etc., and mixtures composed of two or more thereof Or a copolymer can be mentioned. A foaming agent or gas is injected into these materials and used as a foam.

On the other hand, the surface layer (B2) is desirably in the form of a film capable of easily achieving both high strength and surface smoothness. Materials used for the surface layer (B2) include polyethylene, polypropylene, polystyrene, polyisobutylene, polyester, polyurethane, polyamide, polyimide, polyamideimide, alcohol-soluble nylon, polycarbonate, polyarylate, phenol, polyoxymethylene, polyetheretherketone, and polyetheretherketone. Phosphazene,
Thermoplastic resins and thermosetting resins such as polysulfone, polyether sulfide, polyphenylene oxide, polyphenylene ether, polyparabanic acid, polyallylphenol, polybenzimidazole, urea, fluorine, polyurea, ionomer, silicone, and the like, and from two or more of these. And a mixture or a copolymer, which is formed into a film by extrusion molding, injection molding, casting method, centrifugal molding, inflation or the like. In addition, the surface layer (B2) may be used by laminating two or more films made of various materials or by laminating two or more films simultaneously.

(Fourth Invention) An intermediate transfer belt (B) for an image forming apparatus according to a fourth invention of the present invention is a toner obtained by developing an electrostatic latent image formed on an image carrier (16). The image is 1
An intermediate transfer belt (B), which is primary-transferred by a secondary transfer device (T1), and secondary-transferred onto the transfer material (S) by a secondary transfer device (T2); The belt (B) according to claim 1.
It consists of.

(Operation of the Fourth Invention)
The invention intermediate transfer belt (B) is constituted by the belt (B) according to any one of the first to third inventions. The intermediate transfer belt (B) is configured to transfer a toner image obtained by developing an electrostatic latent image formed on the image carrier (16) to a primary transfer device (T).
The primary transfer is performed according to 1). The intermediate transfer belt (B)
The toner image primarily transferred onto the transfer material (S) is secondarily transferred to the transfer material (S) by the secondary transfer device (T2).

(Fifth Invention) A transfer material conveying belt (B) for an image forming apparatus according to a fifth invention of the present invention is an image carrier (56k).
To a transfer area (Q4k to 56c) where a toner image obtained by developing the electrostatic latent image formed on the transfer material (S) is transferred to the transfer material (S).
Q4c) is a transfer material transport belt (B) for transporting the transfer material (S) while electrostatically attracting the transfer material (S), and is constituted by the belt (B) according to any one of claims 1 to 3.

(Operation of the Fifth Invention) The fifth invention having the above-described configuration
The transfer material transport belt (B) of the invention of the invention electrostatically attracts the transfer material (S) and transports it to the transfer area (Q4k to Q4c). In the transfer area (Q4k-Q4c), the image carrier (56k-5
6c) A toner image obtained by developing the electrostatic latent image formed thereon is transferred to the transfer material (S).

(Sixth Invention) A transfer belt (B) for an image forming apparatus according to a sixth invention of the present invention is provided on an image carrier (61) in which an electrostatic latent image formed on the surface is developed into a toner image. A transfer area (Q) is disposed between the image carrier (61) and the image carrier (61).
3) and applying a transfer bias to the back surface of the transfer material (S) passing through the transfer area (Q3) to impart a charge to the toner image on the image carrier (61). A transfer belt (B) for transferring to (S), wherein the belt (B) according to any one of claims 1 to 3.
It consists of.

(Operation of the Sixth Invention) The sixth invention having the above-described configuration
The transfer belt (B) for an image forming apparatus according to the present invention includes an image carrier (6) in which an electrostatic latent image formed on the surface is developed into a toner image.
The transfer area (Q3) is formed between the image carrier (61) and the image carrier (61). The transfer area (Q3)
A transfer bias is applied to the back surface of the transfer material (S) passing through the transfer member (S) to apply an electric charge to the image carrier (61).
The upper toner image is transferred to the transfer material (S).

(Seventh Invention) An image forming apparatus according to a seventh invention of the present invention uses the belt (B) according to any one of the first to sixth aspects.

(Operation of the Seventh Invention) The seventh embodiment having the above-described configuration
In the image forming apparatus of the present invention, the belt (B) used is
The operation of any of the first to sixth inventions is achieved.

[0036]

Next, specific examples (embodiments) of an embodiment of the image forming apparatus of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

[0037]

Next, specific examples (examples) of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. (Embodiment 1 of Belt B) FIG. 1 is an explanatory view of Embodiment 1 of a belt B for an image forming apparatus. FIG. 1A is a side view, and FIG. 1B is a sectional view taken along the line IB-IB in FIG. 1A. In FIG.
The belt B of Example 1 has a base layer B1, a surface layer B2, and an adhesive layer B3 for bonding them. The belt B for the image forming apparatus shown in FIG. 1 was manufactured by a manufacturing method described below.

(Base Layer B1) First, a semiconductive rubber sheet having ethylene-propylene rubber (EPDM) as a main component and a thickness of 300 μm was prepared by the following composition. EPDM 100 parts by weight Conductive carbon 8 parts by weight Reinforcing carbon 20 parts by weight Vulcanizing agent 1 part by weight Vulcanization accelerator 2 parts by weight Vulcanizing aid 2 parts by weight Dispersing aid 0.5 part by weight Plasticizer 20 parts by weight The properties of the obtained sheet are as follows. Surface resistivity 5 × 10 ¹⁰ Ω / □ Volume resistivity 2 × 10 ⁸ Ωcm Tensile modulus 3000 kg / cm ²

(Surface B2) Separately from this, a semiconductive belt having a thickness of 100 μm, a diameter of 200 mm and a width of 320 mm containing polyarylate as a main component was prepared by centrifugal molding. Polyarylate 100 parts by weight Carbon black 8 parts by weight Silicon-based additive 1 part by weight The properties of the obtained belt are as follows. Surface resistivity 2 × 10 ¹¹ Ω / □ Volume resistivity 4 × 10 ⁹ Ωcm Tensile modulus 25000 kg / cm ²

A conductive acrylic adhesive is applied to the inner surface of the polyarylate belt (surface layer B2) prepared in this manner, and the EPDM sheet (base layer B1) prepared above is bonded to form a belt composed of the base layer B1 and the surface layer B2. B was obtained. The belt B has a thin adhesive layer B between the base layer B1 and the surface layer B2.
3 are formed. The electrical resistance of the obtained belt B is as follows. Surface resistivity 2 × 10 ¹¹ Ω / □ Volume resistivity 4 × 10 ⁹ Ωcm

The belt B of the first embodiment is used as the intermediate transfer belt B of the full-color image forming apparatus shown in FIG. 2, and is attached while applying a tension of 4 kg to the intermediate transfer belt B. Image evaluation was performed.
As a result, the registration deviation was 20 μm or less, the hollow area hardly occurred, and the belt B did not meander in 10,000 continuous image prints, and the image after running was a good image having no change from the initial image. Met.

(Embodiment 1 of Image Forming Apparatus) FIG. 2 is an explanatory view of Embodiment 1 of an image forming apparatus using the belt B shown in FIG. In FIG.
The image forming apparatus F includes a UI (user interface),
And a transparent platen glass 2 on which a document (not shown) is placed.

The original placed on the platen glass 2 is illuminated by the light source 4 of the original illumination unit 3. The original reflected light is reflected by the first mirror 5 of the original illuminating unit 3 and the second mirror 7 and the third mirror 8 of the mirror unit 6, passes through the imaging lens 9, and is converted by the CCD into an analog signal of R, G, and B. Is read as The image signal read by the CCD is input to the IPS controlled by the controller C. The IPS image read data output unit 11 converts the input read image signal from analog to digital and outputs the read image signal.
Reference numeral 2 denotes an image memory 13 for converting the AD-converted data into Y, M, C, and K image data, performing data processing such as density correction and enlargement / reduction correction, and writing image data (laser Drive data).

The laser drive signal output device 14 is provided with the IP
A laser drive signal of an image corresponding to the image data output from S is output to a ROS (optical scanning device, that is, a latent image forming device) at a predetermined timing. The ROS outputs a laser beam L modulated by the laser drive signal. After the rotating image carrier 16 is charged by the charger 17, at the latent image writing position Q 1, K (black), Y (yellow), M (magenta), and C (cyan) are applied by the laser beam L. An electrostatic latent image corresponding to the image of each color component is written. A rotary developing unit 18 for developing the electrostatic latent image into a toner image includes developing devices 18k for each color of K (black), Y (yellow), M (magenta), and C (cyan) which rotate with a rotation shaft 18a. Each of the developing devices 18k to 18c rotates to a developing area Q2 facing the image carrier 16 to form an electrostatic latent image corresponding to the image of each color component into a toner of each color. Develop into an image.

The toner image formed on the surface of the image carrier 16 passes through a primary transfer area Q3 facing the intermediate transfer belt B. A primary transfer unit T1 disposed on the back side of the intermediate transfer belt B in the primary transfer area is provided with a primary transfer voltage (a voltage having a polarity opposite to the polarity of the toner charge, supplied from a power supply circuit D).
For example, the toner image on the image carrier 16 is primarily transferred to the intermediate transfer belt B by + (plus) about 1 to 4 kV). The residual toner on the surface of the image carrier 16 that has passed through the primary transfer area Q3 is removed by the image carrier cleaner 20.

The intermediate transfer belt B includes a driving roll 26,
A plurality of belt support rolls (that is, belt support members) 26 including a tension roll 27, an idler roll 28, and an inner secondary transfer roll (backup roll) 29
To 29 so as to be rotatable. The inner secondary transfer roll (backup roll) 29, which is a support roll for the intermediate transfer belt B, is
The electrode roll 31 is configured as a zero counter electrode, and its surface is in contact with the electrode roll 31. The outer secondary transfer roll 30 includes:
It is arranged so as to be separated or approachable between a separated position separated from the inner secondary transfer roll 29 and a pressed close position, and is grounded (grounded). The inner secondary transfer roll 29, the outer secondary transfer roll 30, and the electrode roll 31 constitute a secondary transfer unit T2.

A negative (-) secondary transfer voltage (a voltage having the same polarity as the charged polarity of the toner) is applied from the power supply circuit D to the electrode roll 31 of the secondary transfer device T2. The secondary transfer unit T2 transfers a secondary transfer area Q4 formed by the nip (contact area) between the outer secondary transfer roll 30 and the intermediate transfer belt B to a recording sheet (that is, a transfer material) S.
Is passed, the toner image primarily transferred onto the intermediate transfer belt B is secondarily transferred onto the recording sheet S.

The secondary transfer roll cleaner 33 is a member for removing the toner adhered to the outer secondary transfer roll 30 and, together with the outer secondary transfer roll 30, removes the toner from the inner secondary transfer roll 29. Move in the direction of separation or approach. A belt cleaner 35 is disposed along the surface of the intermediate transfer belt B and downstream of the secondary transfer area Q4. The belt cleaner 35 is disposed so as to be separated from or contact with the intermediate transfer belt B. When a color image is formed, the outermost unfixed toner image is primarily transferred onto the intermediate transfer belt B until the outermost unfixed toner image is transferred.
The next transfer roll 30, the secondary transfer roll cleaner 33, and the belt cleaner 35 are held at positions separated from the intermediate transfer belt B.

Further, a belt position sensor SN1 for detecting a position detection mark (not shown) formed at the outer end of the intermediate transfer belt B in the width direction is provided.
The timing of writing a latent image on the image carrier 16 is controlled by a very accurate position detection signal of the intermediate transfer belt B output from the belt position sensor SN1. The recording sheet S stored in the paper feed tray 41 is taken out by the pickup roll 42,
The sheets are separated one by one, temporarily stopped by the registration rollers 44, and conveyed from the guide conveyance path 45 to the secondary transfer area Q4 at a predetermined timing. The recording sheet S on which the toner image has been secondarily transferred when passing through the secondary transfer area Q4 is conveyed to the fixing area Q6 by the sheet guide 46 and the sheet conveying belt 47.
When passing through the fixing area Q6, the secondary transfer toner image on the recording sheet S is fixed by a pair of fixing rolls of a fixing device 48 and is discharged to a paper discharge tray 49. The recording sheet transporting device (that is, the transfer material transporting device) (42 to 47) is configured by the elements indicated by the reference numerals 42 to 47.

When forming a monochromatic image, the primary transfer area, Q3
The toner image primarily transferred to the intermediate transfer belt B is secondarily transferred to the recording sheet S immediately in the secondary transfer area Q4. At the time of full-color image formation, each time the intermediate transfer belt B passes through the primary transfer area Q3, the toner image of each color is sequentially superimposed on the intermediate transfer belt B and primary-transferred. After the primary transfer on B
The secondary transfer is collectively performed on the recording sheet S in the secondary transfer area.

Embodiment 1 of the image forming apparatus F having the above-described configuration is similar to Embodiment 1 of the belt B as an intermediate transfer belt.
Since the belt described above is used, the same operation as the operation of the belt B described in the first embodiment is achieved.

(Example 2 of Belt B) (Base Layer B1) A semiconductive rubber sheet having chloroprene rubber as a main component and a thickness of 300 μm was prepared by the following composition. Chloroprene rubber 100 parts by weight Conductive carbon 5 parts by weight Reinforcing carbon 10 parts by weight Vulcanizing agent 1 part by weight Vulcanization accelerator 2 parts by weight Vulcanizing aid 2 parts by weight Dispersing aid 0.5 part by weight Plasticizer 15 parts by weight The properties of the obtained sheet are as follows. Surface resistivity 3 × 10 ⁹ Ω / □ Volume resistivity 5 × 10 ⁷ Ωcm Hardness (JIS-A) 70

(Surface B2) Separately from this, a semiconductive film having a thickness of 100 μm and containing ethylene tetrafluoroethylene (ETFE) as a main component was prepared by extrusion with the following composition. ETFE 100 parts by weight Carbon black 5 parts by weight The properties of the obtained film are as follows. Surface resistivity 6 × 10 ¹¹ Ω / □ Volume resistivity 1 × 10 ¹⁰ Ωcm Hardness (ASTMD-785) 120

A conductive acrylic adhesive was applied to the inner surface of the ETFE belt (surface layer B2) thus produced,
The chloroprene rubber sheet (base layer B1) prepared above was bonded to obtain a belt B in which the base layer B1 and the surface layer B2 were bonded with the bonding layer B3. The electrical resistance of the obtained belt B is as follows. Surface resistivity 6 × 10 ¹¹ Ω / □ Volume resistivity 4 × 10 ⁸ Ωcm

The belt B of the second embodiment is used as the intermediate transfer belt B of the full-color image forming apparatus F shown in FIG. 2, and is attached while giving a tension of 4 kg to the intermediate transfer belt B. Image evaluation was performed. As a result, the misregistration was 20 μm or less, the hollow area hardly occurred, the belt B did not meander even in 10,000 full-color continuous printing, and the image after running was a good image having no change from the initial image. Was something.

(Example 3 of belt B) (Urethane material for forming base layer B1) A urethane material (material for forming base layer B1) which was made semiconductive and sufficiently stirred and foamed was prepared by the following composition. Polyol 50 parts by weight Isocyanate 50 parts by weight Quaternary ammonium salt 1 part by weight In Example 3, the urethane material for forming the base layer B1 was:
Since the belt B is manufactured by pouring into the inner surface of the surface layer B2 as described later, it is not necessary to manufacture a sheet including only the base layer B1, but in order to measure characteristics when the base layer B1 is formed into a sheet, the urethane is used. The material was injected into an injection mold to obtain a 500 μm thick sheet. The properties of the obtained urethane foam rubber sheet are as follows. Surface resistivity 4 × 10 ⁹ Ω / □ Volume resistivity 5 × 10 ⁷ Ωcm Tensile modulus 3500 kg / cm ² Hardness (JIS-A) 45

(Surface layer B2) Separately from this, a thermosetting polyimide as a main component has a thickness of 300 μm and a diameter of 200 μm.
A semiconductive belt having a width of 320 mm and a width of 320 mm was produced by centrifugal molding. Polyarylate 100 parts by weight Carbon black 10 parts by weight The properties of the obtained belt are as follows. Surface resistivity 8 × 10 ¹¹ Ω / □ Volume resistivity 1 × 10 ¹⁰ Ωcm Tensile modulus 35,000 kg / cm ² Hardness (ASTMD-785) 140

Next, the thermosetting polyimide belt (surface layer B2) was attached to a mold cylinder, and the inner surface of the belt was
A metal core maintaining a gap of 0 μm was attached, and a urethane material (urethane material for forming the base layer B1) sufficiently mixed with the above-mentioned mixture was poured into the gap between the belt and the core.
And a belt B integrally formed with the surface layer B2. The electrical resistance of the obtained belt is as follows. Surface resistivity 8 × 10 ¹¹ Ω / □ Volume resistivity 9 × 10 ⁹ Ωcm

Next, the obtained belt B is used as an intermediate transfer belt B of the full-color image forming apparatus F shown in FIG. 2 and is attached while giving a tension of 4 kg to the intermediate transfer belt B. Image evaluation was performed.
As a result, the misregistration was 10 μm or less, no hollowing occurred, the belt B did not meander even after printing 10000 continuous images, and the image after running was a good image with no change from the initial image. Met.

Comparative Example 1 of Belt (Base Layer B1) A semiconductive rubber sheet having a thickness of 300 μm and containing styrene-butadiene rubber (SBR) as a main component was prepared by the following composition. SBR 100 parts by weight Conductive carbon 7 parts by weight Reinforcing carbon 40 parts by weight Vulcanizing agent 1 part by weight Vulcanization accelerator 2 parts by weight Vulcanizing aid 2 parts by weight Dispersing aid 0.5 part by weight Plasticizer 5 parts by weight The properties of the obtained sheet are as follows. Surface resistivity 4 × 10 ¹⁰ Ω / □ Volume resistivity 6 × 10 ⁸ Ωcm Tensile modulus 12000 kg / cm ²

The SBR of Comparative Example 1 thus manufactured
The sheet (base layer B1) has a tensile modulus of 12,000 kg /
cm^TwoIs the upper limit value of the base layer B1 of the present invention (= 10000 kg /
cm ^TwoHigher). This base layer B1 was prepared in Example 1.
Conductive acrylic with polyarylate film (surface layer B2)
Laminated using a polyarylate film
The outer periphery (surface layer B2) and join the ends by ultrasonic welding
A belt B having a base layer B1 and a surface layer B2 was prepared. Get
The electrical resistance of the belt B is as follows. Surface resistivity 6 × 10¹¹Ω / □ Volume resistivity 2 × 10⁹Ωcm

Next, the obtained belt B was used as an intermediate transfer belt B for a full-color image forming apparatus shown in FIG. 2 and attached while applying a tension of 4 kg, and image evaluation was performed mainly on registration deviation and hollowing out. . As a result, in the initial image, there was no misregistration, but the inside of the belt B was meandering in continuous image printing.

(Comparative Example 2 of Belt) (Base Layer B1) The semiconductive rubber sheet having a thickness of 300 μm and containing ethylene-propylene rubber (EPDM) as a main component and manufactured in Example 1 was used as the base layer B1. (Surface layer B2) Thickness of 100 μm mainly composed of polyethylene (PE) obtained by extrusion molding with the following composition
m (surface layer B2). PE 100 parts by weight Carbon black 3 parts by weight The properties of the obtained belt are as follows. Surface resistivity 2 × 10 ¹¹ Ω / □ Volume resistivity 4 × 10 ⁹ Ωcm Tensile modulus 12000 kg / cm ²

The PE film of Comparative Example 2 (surface layer B 2) thus produced had a tensile modulus of 12,000 kg /
cm ² is the lower limit of the surface layer B2 of the present invention (15000 kg / c
m ² ). EPDM sheet (base layer B1) and P
An E film (surface layer B2) is bonded using a conductive acrylic adhesive, and the ends are joined by ultrasonic welding to form a base layer B1.
A belt B having a surface layer B2 was produced. The electrical resistance of the obtained belt B is as follows. Surface resistivity 2 × 10 ¹¹ Ω / □ Volume resistivity 2 × 10 ⁹ Ωcm

Next, the obtained belt B was used as the intermediate transfer belt B of the full-color image forming apparatus F shown in FIG. 2 and attached while applying a tension of 4 kg, and the image evaluation was carried out with a focus on the misregistration and the void. As a result, meandering and hollowing did not occur, but a good image was not obtained due to severe misregistration.

(Modifications) Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above-mentioned embodiments, but falls within the scope of the present invention described in the appended claims. Thus, various changes can be made. Modified embodiments of the present invention will be exemplified below. (H01) The belt of the present invention can be used, for example, as a recording sheet transport belt for an image forming apparatus. FIG. 3 is a schematic explanatory view of an image forming apparatus using the belt of the present invention as a recording sheet conveying belt (that is, a belt for the image forming apparatus). In FIG. 3, the recording sheet transport belt B is rotated in a direction indicated by an arrow A at a constant process speed (for example, 70 mm / min) by a plurality of belt support rolls (belt support members) 51 to 54 including a drive roller 51. A voltage of +500 V is applied to the attraction roller 55 that attracts the recording sheet S to the recording sheet transport belt B, and charges the recording sheet S entering from the direction of arrow E. K (black), Y along the moving direction of the recording sheet conveying belt B
(Yellow), M (magenta), and C (cyan) image carriers 56k to 56c are arranged.
k-56c, the charging roller 57 is provided upstream of the latent image writing positions Q1k-Q1c along the moving direction of the image carrier.
k to 57c are arranged, and downstream from the latent image writing positions Q1k to Q1c, the developing devices 58k to 58c, the transfer rollers Tk to Tc,
Cleaners 59k to 59c are arranged. The transfer rollers Tk to Tc are formed of image carriers 56k to
The recording sheet conveying belt B is disposed at a position opposite to the recording sheet conveying belt B, and transfer areas Q4k to Q4c are formed between the image bearing members 56k to 56c and the recording sheet conveying belt B. The transfer rollers Tk to Tc are formed on the image carriers 56k to 56c when the recording sheet S conveyed by being attracted to the recording sheet conveying belt B passes through the transfer areas Q4k to Q4c. The toner images of each color are transferred to the recording paper S. As the recording sheet conveying belt B shown in FIG. 3, any of the belts described in the first to third embodiments of the belt is used. Since the recording sheet conveying belt B using any one of the above-mentioned belts has little meandering, it is possible to transfer a transfer image with little displacement on the recording paper S.

(H02) The belt of the present invention can be used as a transfer belt for transferring a toner image on an image carrier to a recording sheet S passing through a transfer area of an image forming apparatus, for example. FIG. 4 is a schematic explanatory view for an image forming apparatus using a transfer belt for transferring a toner image on an image carrier to a recording sheet S passing through a transfer area. After the rotating image carrier 61 is charged by the charger 62, an electrostatic latent image is written by the laser beam L at the latent image writing position Q1. The electrostatic latent image on the image carrier 61 is developed into a toner image by the developing device 63 in the developing area Q2, and is conveyed to the transfer area Q3. The transfer area Q3 is an area between the transfer belt B rotated by belt support rolls (belt support members) 66 and 67 and the image carrier 61. A transfer bias applying roll 64 is disposed on the back side of the transfer belt B in the transfer area Q3,
A cleaner 65 is disposed downstream of the transfer area Q3 in the moving direction of one surface. On the back surface of the recording sheet S passing through the transfer area Q3, a transfer bias applying roll 6 is provided.
4, a transfer bias is applied via the transfer belt B. The toner image on the surface of the image carrier 61 is transferred to the recording sheet S by the transfer bias applied via the transfer belt B. Image carrier 61 that has passed the transfer area Q3
The toner remaining on the surface is removed by the cleaner 65, and the toner adhered to the surface of the transfer belt B is removed by the belt cleaner 68. As the transfer belt B shown in FIG. 4, any one of the belts described in Embodiments 1 to 3 of the belt is used. Since the transfer belt B using any one of the above-mentioned belts has little meandering, a transfer image with little displacement can be transferred onto the recording sheet S.

(H03) As the belt support member of the present invention, instead of using a plurality of belt support members, for example, it is possible to use a drum that supports the belt with its surface wound.

[0069]

As described above, the present invention having the functions separated into the surface layer and the base layer has the following effects. (E01) Since the surface layer having a high tensile modulus (rigidity) suppresses the deformation (elongation) of the belt due to the stress at the time of driving, the resist is less likely to be misaligned. (E02) The base layer that is easily elastically deformed reduces the aggregation of toner due to the concentration of the pressing force by the bias roller at the transfer portion, prevents the image from dropping out, and also prevents the belt from meandering. (E03) It is possible to provide an intermediate transfer belt, a transfer material conveying belt, a transfer belt, and an image forming apparatus using the same, which can realize low cost without requiring a rib or a meandering prevention device.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a belt B for an image forming apparatus.
FIG. 1A is a side view, and FIG.
It is a B-IB line sectional view.

FIG. 2 is an explanatory view of Embodiment 1 of the image forming apparatus using the belt B shown in FIG. 1 as an intermediate transfer belt B.

FIG. 3 is a schematic explanatory view of an image forming apparatus using the belt of the present invention as a recording sheet conveying belt.

FIG. 4 is a schematic explanatory view for an image forming apparatus using a transfer belt for transferring a toner image on an image carrier to a recording sheet passing through a transfer area.

[Explanation of symbols]

B: belt for image forming apparatus, B1: base layer, B2: surface layer,
F: image forming apparatus, Q3: transfer area, Q4k to Q4c: transfer area, S: transfer material (recording sheet), T1: primary transfer unit,
T2: Secondary transfer unit, 16, 56k to 56c, 61: Image carrier, 25 to 29, 51 to 54, 66 to 67: Belt support member (belt support roll).

Claims (7)

[Claims] 1. A belt used in an image forming apparatus in which an electrostatic latent image formed on an image carrier is developed into a toner image and the toner image is transferred to a transfer material, comprising: a base layer; In a belt for an image forming apparatus having a surface layer laminated on a front surface side and a back surface side of the base layer rotatably supported by the belt support member, a tensile elastic modulus of the base layer is 10,000 kg / cm ² or less, and The tensile modulus of the surface layer is 15,000 kg /
cm. ² or more. 2. A belt for use in an image forming apparatus in which an electrostatic latent image formed on an image carrier is developed into a toner image and the toner image is transferred to a transfer material. In a belt for an image forming apparatus having a surface layer laminated on a front surface side and a back surface side of the base layer rotatably supported by the belt support member, the hardness of the base layer is 90 or less in JIS-A hardness, and A belt for an image forming apparatus, wherein the hardness of the surface layer is 60 or more in ASTM D-785. 3. A belt used in an image forming apparatus in which an electrostatic latent image formed on an image carrier is developed into a toner image and the toner image is transferred to a transfer material, comprising: a base layer; A belt for an image forming apparatus having a surface layer laminated on a front surface side and a back surface side of the base layer rotatably supported by the belt support member, wherein the base layer is a foam, and the surface layer is a film A belt for an image forming apparatus, comprising: 4. A toner image obtained by developing an electrostatic latent image formed on an image carrier is primarily transferred by a primary transfer device, and the primary transferred toner image is transferred by a secondary transfer device. An intermediate transfer belt that is secondary-transferred onto a transfer material, wherein the intermediate transfer belt includes the belt according to any one of claims 1 to 3. 5. A transfer material transport for transporting a transfer material while electrostatically attracting the transfer material to a transfer area where a toner image obtained by developing the electrostatic latent image formed on the image carrier is transferred to the transfer material. A transfer material transport belt comprising a belt, the transfer material transport belt including the belt according to claim 1. 6. An electrostatic latent image formed on a surface is disposed to face an image carrier to be developed into a toner image to form a transfer area between the image carrier and the image carrier. The transfer belt according to claim 1, wherein the transfer belt transfers a toner image on the image carrier to the transfer material by applying a transfer bias to a rear surface of the passing transfer material and applying a charge. A transfer belt constituted by the belt. 7. An image forming apparatus using the belt according to claim 1.