JP2000347513A - Intermediate transfer belt, manufacture thereof and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an intermediate transfer belt whose characteristic is not changed even when it is hardly and enduringly used by being repeatedly used and whose characteristic being identical to that of an initial time can be maintained, the manufacturing method thereof and an image forming device. SOLUTION: An intermediate transfer body is used for an image forming device constituted so that an image formed on a 1st image carrier is transferred on the intermediate transfer body and transferred on a 2nd image carrier besides thereafter. Then, the intermediate transfer body is obtained by cylindrically melting and extruding material for molding by using an extruding machine and a annular die and constituted of polyamide having at least an aromatic ring at a principal chain. Besides, the thickness thereof is thinner than the die gap of the annular die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an electrophotographic image forming apparatus in which a toner image formed on a first image carrier is once transferred to an intermediate transfer member and then further transferred to obtain an image formed product. The present invention relates to an intermediate transfer belt, a method for manufacturing the same, and an image forming apparatus using the intermediate transfer belt.

[0002]

2. Description of the Related Art An image forming apparatus using an intermediate transfer belt sequentially transfers a plurality of component color images of color image information and multicolor image information in a layered manner to form an image formed product in which a color image or a multicolor image is synthesized and reproduced. The present invention is effective as a color image forming apparatus or a multicolor image forming apparatus for outputting, or an image forming apparatus having a color image forming function or a multicolor image forming function.

FIG. 1 is a schematic view showing an example of an image forming apparatus using an intermediate transfer belt as an intermediate transfer member.

FIG. 1 shows a color image forming apparatus (copier or laser beam printer) using an electrophotographic process. The intermediate transfer belt 20 uses a medium-resistance elastic body.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) which is repeatedly used as a first image carrier, and rotates at a predetermined peripheral speed (process speed) clockwise as indicated by an arrow. Driven.

[0006] The photosensitive drum 1 rotates in the primary charging device 2 during the rotation process.
Is charged uniformly to a predetermined polarity and potential, and then image exposure means 3 (not shown) (modulation in accordance with a color original image separation / imaging exposure optical system, a time-series electric digital pixel signal of image information) (E.g., a scanning exposure system using a laser scanner that outputs a converted laser beam) to form an electrostatic latent image corresponding to a first color component image (for example, a yellow color component image) of a target color image. You.

Next, the electrostatic latent image is developed by a first developing device (yellow developing device 41) with yellow toner Y as a first color. At this time, the developing units of the second to fourth developing units (magenta developing unit 42, cyan developing unit 43, black developing unit 44) are turned off and do not act on the photosensitive drum 1, The first color yellow toner image is not affected by the second to fourth developing units.

The intermediate transfer belt 5 is driven to rotate at the same peripheral speed as the photosensitive drum 1 in the direction of the arrow.

[0009] The first type formed and supported on the photosensitive drum 1
In the process in which the yellow toner image of the color passes through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 5, the electric field formed by the primary transfer bias applied from the primary transfer roller 6 to the intermediate transfer belt 5 causes Intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5.

The surface of the photosensitive drum 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5 is finished.
The cleaning is performed by the cleaning device 12.

[0011] Similarly, a magenta toner image of the second color, a cyan toner image of the third color, and a black toner image of the fourth color are successively superimposed on the intermediate transfer belt 5 and transferred to correspond to the target color image. Thus, a combined color toner image is formed.

Reference numeral 7 denotes a secondary transfer roller, which is provided in parallel with the secondary transfer opposing roller 8 so as to be capable of being separated from the lower surface of the intermediate transfer belt 5 and bearing therewith.

A primary transfer bias for sequentially superimposing transfer of the first to fourth color toner images from the photosensitive drum 1 to the intermediate transfer belt 5 is applied from a bias power supply 14 with a polarity (+) opposite to that of the toner. You. The applied voltage is, for example, +100 V
２2 kV.

In the primary transfer step of the first to third color toner images from the photosensitive drum 1 to the intermediate transfer belt 5, the secondary transfer roller 7 can be separated from the intermediate transfer belt 5.

The transfer of the composite color toner image transferred onto the intermediate transfer belt 5 to a transfer material P, which is a second image carrier, is performed while the secondary transfer roller 7 is in contact with the intermediate transfer belt 5 and The transfer material P is fed from the paper feed roller 11 through the transfer material guide 10 to the contact nip between the intermediate transfer belt 5 and the secondary transfer roller 7 at a predetermined timing, and the secondary transfer bias is changed from the power supply 15 to the power supply 15. It is applied to the next transfer roller 7. With this secondary transfer bias, the composite color toner image is transferred (secondary transfer) from the intermediate transfer belt 5 to the transfer material P as the second image carrier. The transfer material P to which the toner image has been transferred is introduced into the fixing device 13 and is fixed by heating.

After the image transfer to the transfer material P is completed, the cleaning member 9 is brought into contact with the intermediate transfer belt 5, so that the toner remaining on the intermediate transfer belt 5 without being transferred to the transfer material P ( The transfer residual toner) is cleaned. The cleaning member 9 is disposed so as to be able to be separated from the intermediate transfer belt 5.

In a color electrophotographic apparatus having an image forming apparatus using the above-mentioned intermediate transfer belt, a second image carrier is attached or adsorbed on a transfer drum, which is a conventional technique, and the first image carrier is Compared with a color electrophotographic apparatus having an image forming apparatus for transferring an image from the body, for example, a transfer apparatus as described in JP-A-63-301960, a transfer material as a second image carrier The image can be transferred from the intermediate transfer belt without requiring any processing or control (for example, gripping by a gripper, adsorbing, giving a curvature, etc.), so that envelopes, postcards,
From thin paper (40 g / m ² paper) to thick paper (2
(00 g / m ² paper), the second image bearing member has an advantage that it can be variously selected irrespective of its width, length, or thickness.

Due to such advantages, color copying machines and color printers using an intermediate transfer belt have begun to move in the market.

Polyalkylene terephthalate resins, polyolefin resins, fluororesins, and the like have already been proposed as materials used for belts, films, and tubes that can be used for the intermediate transfer member and the like (Japanese Patent Application Laid-Open No. Hei 6-1).
49081, JP-A-5-31016, JP-A-7-24912, JP-A-5-200904, JP-A-6-228335 and the like.

However, when the resistance controlling agent is dispersed in the polyalkylene terephthalate resin, a remarkable decrease in mechanical properties is observed, and when the intermediate transfer belt is used for a long period of time, problems such as tearing and cracking of the belt may occur. Occurred in some cases.

Further, the polyolefin-based resin has remarkable uniform dispersion of the resistance control agent, and when used as an intermediate transfer belt, uniform transferability may not be obtained in some cases.

Further, since the fluorine-based resin material is excellent in releasing property, when it is used as an intermediate transfer belt, high transfer efficiency is easily obtained in part, but it is used for a long time due to poor mechanical properties. In such a case, the intermediate transfer belt may be elongated, causing problems such as slippage, meandering, and uneven peripheral speed of the belt. At the same time, uniform dispersion of the resistance control agent is difficult as in the case of the polyolefin resin, and uniform transfer is performed. It was difficult to get the performance.

On the other hand, various methods for producing a belt and a tube used for an intermediate transfer belt have already been known. For example, JP-A-3-89357 and JP-A-5-345
Japanese Patent Publication No. 368 proposes a method for manufacturing a semiconductive belt by extrusion molding. In addition, Japanese Patent Application Laid-Open No. 5-2698
In Japanese Patent Publication No. 49, sheets are joined to form a cylindrical shape,
A method for obtaining a belt has been proposed. Further, Japanese Unexamined Patent Publication No.
Japanese Patent No. 269,674 proposes a method of forming a multilayer coating film on a cylindrical substrate and finally removing the substrate to obtain a belt. On the other hand, JP-A-5-77252
In Japanese Patent Laid-Open Publication No. HEI 9-204, there is a proposal of a seamless belt by a centrifugal molding method.

Some belt and film inventions using polyamide have already been disclosed. For example, there are JP-A-63-31263 and JP-A-9-90716. JP-A-63-31263 discloses an intermediate transfer member obtained by casting a wholly aromatic polyamide or polyimide.
No. 716 relates to a functional roll having a heat-shrinkable polyamide elastomer tube.

[0025]

The above-mentioned prior arts have respective advantages and disadvantages, and none of them is satisfactory. For example, in extrusion molding, simply setting the die gap of the extrusion die to the same dimension as the desired belt thickness and molding it, for example, has a considerable difficulty in molding a thin film of 100 μm or less. Thickness unevenness is caused, and accordingly, unevenness of electric resistance is apt to occur, which hinders performance and quality stability as an intermediate transfer member. In addition, when joining sheet-like films, there is a problem of a step at joints and a decrease in strength. Furthermore, methods using a solvent such as cast molding, coating, and centrifugal molding increase the number of steps and costs, such as production of a coating solution, coating, and removal of the solvent, and also include matters that affect the environment such as solvent recovery. In.

Therefore, the present inventors propose a new intermediate transfer belt, a method of manufacturing an intermediate transfer belt, and an image forming apparatus which are different from the conventional ones and which solve the above-mentioned problems.
An object of the present invention is to manufacture an intermediate transfer belt and an intermediate transfer belt that can maintain the same characteristics as those of the initial state without changing the characteristics of the intermediate transfer belt even when subjected to severe durability by repeated use of the intermediate transfer belt. A method and an image forming apparatus are provided.

Another object of the present invention is to provide an intermediate transfer belt, a method of manufacturing an intermediate transfer belt, and an image forming apparatus capable of obtaining a uniform image with very little resistance unevenness.

Another object of the present invention is to provide a method of manufacturing an intermediate transfer belt which is low in cost, has a small number of steps, and is excellent in versatility.

[0029]

The present invention is used in an image forming apparatus for transferring an image formed on a first image carrier to an intermediate transfer member, and further transferring the image on a second image carrier. In the intermediate transfer member, obtained by extruding a molding material into a cylindrical shape using an extruder and an annular die, a polyamide having an aromatic ring in at least the main chain, and a die gap of the annular die It is characterized by its small thickness.

According to the present invention, there is provided a method for manufacturing an intermediate transfer member used in an image forming apparatus for transferring an image formed on a first image carrier to an intermediate transfer member and further transferring the image onto a second image carrier. In the method, a molding material comprising a polyamide having an aromatic ring at least in a main chain is extruded using an extruder and an annular die, the thickness is smaller than the die gap of the annular die, and the diameter is smaller than the diameter of the annular die. 50-4
Disclosed is a method for producing an intermediate transfer belt, which is characterized in that the intermediate transfer belt is melt-extruded into a cylindrical shape so as to be 50%.

[0031]

FIG. 2 shows a molding apparatus applied to the present invention. This device basically comprises an extruder, an extrusion die (annular die) and, if necessary, a gas blowing device. Although two extruders 100 and 110 are provided for molding a two-layer belt, at least one or more extruders may be used in the present invention.

Next, a method for manufacturing a single-layer intermediate transfer belt will be described. First, after preliminarily mixing a molding resin, a resistance controlling agent, an additive, and the like based on a desired prescription, the kneaded and dispersed molding raw material is put into a hopper 120 provided in the extruder 100. In the extruder 100, the set temperature and the configuration of the extruding screw are selected so that the raw material for molding has a melt viscosity that enables the belt to be formed in a later step, and the raw materials are uniformly mixed. The raw material for molding is extruder 10
And melted and kneaded in a molten state in an extrusion die 140.
to go into. The extrusion die 140 is provided with a gas introduction path 150, and when the gas is blown into the extrusion die 140 from the gas introduction path 150, the melt that has passed through the die 140 is expanded and expanded in the radial direction, and is larger than the die gap. The thickness of the molded product is reduced.

At this time, as the gas to be blown, various gases such as air, nitrogen, carbon dioxide, and argon can be appropriately selected. The expanded molded body is pulled up while being cooled by the cooling ring 160. At this time, by passing between the dimension stability guides 170, the final shape dimension 180 is determined. Further, by cutting this into a desired width, the intermediate transfer belt 1 of the present invention is cut.
90 can be obtained.

Although the above description has been made with reference to a single-layer belt, in the case of two or more layers, an extruder 110 is further arranged as shown in FIG. The raw material for molding fed from the hopper 130 is fed into the extrusion die 140 as a kneaded melt from the extruder 110, and two layers are simultaneously expanded and expanded to obtain a two-layer belt. Of course, in the case of three or more layers, the number of extruders corresponding to the number of layers may be prepared.

FIG. 4 shows an example of an intermediate transfer belt having a two-layer structure, and FIG. 5 shows an example of an intermediate transfer belt having a three-layer structure.

As described above, according to the present invention, not only a single layer but also a multi-layered intermediate transfer belt can be formed with high dimensional accuracy in a single step and in a short time. The fact that short-time molding is possible sufficiently indicates that mass production and low-cost production are possible.

FIG. 3 shows another example of a method of manufacturing an intermediate transfer belt according to the present invention.

The raw material for molding put into the hopper 120 becomes a uniformly dispersed melt in the process of passing through the extruder 100 and is extruded into a cylindrical shape from the extruded annular die 141. The extruded cylindrical molded product becomes thinner than the die gap by being drawn in the extrusion direction at a higher drawing speed than the extrusion discharge speed, and the inner surface of the cylindrical molded product is cooled while contacting the internal cooling mandrel 165. Thereby, the intermediate transfer belt 190 of the present invention is adjusted to a desired size 180.

Here, as a method of making the thickness of the molded product smaller than the die gap of the extruded annular die, a method of expanding the molded product as described above or a method of taking out the molded product faster than the discharge speed of the extruder is used. However, by making the thickness of the obtained intermediate transfer belt thinner than the die gap of the extruded annular die, it is possible to reduce the unevenness in the thickness at the time of extrusion. Problems such as displacement can be prevented. Further, for example, even when an intermediate transfer belt of a thin film having a thickness of 100 μm or less is formed, it is possible to obtain an intermediate transfer belt having a smooth transfer surface without thickness unevenness.

The nylon resin having an aromatic ring in the main chain used in the present invention is different from the materials described in the prior art in that
It has excellent mechanical properties and excellent pigment dispersibility, and when used in the intermediate transfer belt of the present invention, exhibits excellent durability and uniform transferability due to extremely small unevenness in electric resistance.

Here, by setting the diameter of the intermediate transfer belt in the range of 50 to 450% as compared with the diameter of the annular die, it is possible to further reduce unevenness in electric resistance, which is preferable. Here, if the diameter of the intermediate transfer belt is less than 50% or more than 450% as compared with the diameter of the annular die, the cylindrical molded product extruded from the annular die is greatly deformed after being extruded, thereby causing an electric resistance. May easily occur, and uniform transfer performance may not be obtained.

As shown in FIG. 2, when the cylindrical molded product is expanded by blowing gas into the cylindrical molten material discharged from the tip of the annular die by extrusion of the extruder, the cylindrical die is expanded. By expanding the diameter of the molded article in the range of 105 to 400% compared to the diameter,
This is preferable because unevenness in electric resistance and thickness can be reduced.

The polyamide having an aromatic ring in the main chain of the present invention may be any polyamide resin as long as it is a polyamide resin having an aromatic ring in the main chain. Particularly, the polyamide represented by the following general formulas (1) and (2): The compounds represented by the formula (1) are preferred for reasons of excellent mechanical properties, pigment dispersibility, easy moldability and the like.

[0044]

Embedded image Further, the content of the resistance control agent in the intermediate transfer member is preferably 30% by weight or less. If the amount exceeds 30% by weight, the mechanical strength of the polyamide resin of the present invention is reduced, and the intermediate transfer belt may be damaged during long-term use.

Further, the thickness of the intermediate transfer belt is 45-3.
It is preferably in the range of 00 μm. If it is less than 45 μm, problems due to elongation of the intermediate transfer belt are likely to occur during long-term use, and if it exceeds 300 μm, the rigidity is high and the flexibility is poor, and it is difficult to obtain a smooth running property of the intermediate transfer belt.

Here, the resistance value of the intermediate transfer belt is 1 × 1
It is preferably in the range of 0 ³ to 1 × 10 ¹⁴ Ω. When the resistance value of the intermediate transfer belt is less than 1 × 10 ³ Omega is leakage tends to occur between the first image bearing member, exceeds 1 × 10 ¹⁴ Omega, the first image-bearing Since the intermediate transfer belt is significantly charged when the toner is transferred from the body, a peeling discharge occurs between the intermediate transfer belt and the first image carrier, and the toner image may be disturbed. Here, a method of measuring the resistance value of the intermediate transfer belt will be described below.

(1) The intermediate transfer belt 20 is stretched around a drive roll 200 and a metal roll 201 as shown in FIG. 6, and the intermediate transfer belt 20 is fixed to two metal rollers 202 and 2
03, a DC power supply 204, a resistor 205 having a mortgage resistance value, and a potentiometer 206 are connected.

(2) The intermediate transfer belt is driven by the drive roll 200 such that the moving speed of the surface of the intermediate transfer belt becomes 100 mm / sec.

(3) 100 to 100 from DC power supply 204
A voltage is applied in the range of 0 V, and the potential difference Vr across the resistor 205 is read from the potentiometer 206. The atmosphere at the time of measurement is 23 ± 2 ° C. in temperature and 60 ± 10% in humidity.

(4) A current value I flowing through the circuit is obtained from the obtained potential difference Vr.

(5) (Resistance value of intermediate transfer belt) = (applied voltage) / (current value I) The polyamide resin of the present invention has better pigment dispersibility and moldability than the material used for the conventional intermediate transfer belt. When the intermediate transfer belt is manufactured by the method shown in FIGS. 2 and 3, the electric resistance can be easily and uniformly controlled. However, even if a resin having such excellent properties is used, in order to function as the intermediate transfer belt of the present invention, the volume resistivity and / or the surface resistivity of each part of the belt have the maximum value of the minimum value. It is preferable to keep it within 100 times. If there is more resistance unevenness, the resistance unevenness of the belt adversely affects the transferability. Specifically, partial transfer omission may occur in a halftone image or the like.

Means for keeping the maximum value within 100 times the minimum value in the volume resistivity and the surface resistivity of each part of the belt include the compatibility between the resin of the present invention and the resistance controlling agent, and the dispersion processing of the resistance controlling agent. By carefully examining the process conditions at the time, and further the process conditions at the time of belt production, etc., the above range can be achieved.

The method for measuring the surface resistance and the volume resistivity in the present invention will be described below.

<Measuring machine> Resistance meter; super high resistance meter R8340A (manufactured by Advantest) Sample box: material box TR42 for ultrahigh resistance measurement (manufactured by Advantest) However, the main electrode is 25 mm in diameter, and the guard ring electrode is 41 mm in inner diameter , And an outer diameter of 49 mm.

<Sample> The belt is cut into a circle having a diameter of 56 mm. After cutting, one surface is provided with electrodes on the entire surface by a Pt-Pd vapor deposition film, and the other surface is a Pt-Pd vapor deposition film on a main electrode having a diameter of 25 mm, an inner diameter of 38 mm, and an outer diameter of 50 mm.
mm guard electrode is provided. The Pt-Pd vapor-deposited film can be obtained by performing a vapor deposition operation for 2 minutes with mild sputter E1030 (manufactured by Hitachi, Ltd.). The sample after the vapor deposition operation is used as a measurement sample.

<Measurement Conditions> Measurement atmosphere: 23 ° C./55%. The measurement sample is left in an atmosphere of 23 ° C./55% for 12 hours or more.

Measurement mode: Program mode 5 (discharge 10 seconds, charge and measure 30 seconds) Applied voltage: 1 to 1000 (V) The applied voltage depends on the intermediate transfer member and the transfer member used in the image forming apparatus of the present invention. Can be arbitrarily selected from 1 to 1000 V, which is a part of the range of the voltage applied to. Further, the applied voltage used can be changed as appropriate within the above-mentioned applied voltage range according to the resistance value, thickness, dielectric breakdown strength, etc. of the sample. Further, if the volume resistivity and the surface resistance at a plurality of positions measured at any one of the applied voltages are included in the resistance range of the present invention, it is determined that the resistance range is the object of the present invention. You.

Resins other than the main resin used in the intermediate transfer belt of the present invention include, for example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene- Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylate copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylate copolymer, (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Phenyl methacrylate copolymer), styrene-α- Styrene-based resins such as chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer (a homopolymer or copolymer containing styrene or a substituted styrene), methyl methacrylate resin, butyl methacrylate resin, Ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride-vinyl acetate Copolymer, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene,
Polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silicone resin, fluorine resin,
Ketone resin, ethylene-ethyl acrylate copolymer,
One or two or more selected from the group consisting of xylene resin, polyvinyl butyral resin, polyimide resin, polyamide resin, modified polyphenylene oxide resin, etc. can be used, but can be used only in the range that does not hinder the properties of the main resin It is. However, it is not limited to the above materials.

Next, among the resistance control agents for adjusting the electric resistance of the intermediate transfer member of the present invention, examples of the electron conductive resistance control agent include carbon black, graphite, aluminum-doped zinc oxide, and tin oxide coating. Titanium oxide, tin oxide, tin oxide-coated barium sulfate, potassium titanate, aluminum metal powder, nickel metal powder, and the like. Further, as the ion conductive resistance control agent, tetraalkylammonium salt, trialkylbenzyl, ammonium salt, alkyl sulfonate, alkylbenzene sulfonate, alkyl sulfate, glycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine, Polyoxyethylene fatty alcohol ester, alkyl betaine, lithium perchlorate, and the like.

Further, as the first image carrier, it is preferable to use a photosensitive drum containing at least the outermost layer containing a fine powder of PTFE, since higher primary transfer efficiency can be obtained. This is considered to be because the surface energy of the outermost layer of the photosensitive drum is reduced by containing the fine powder of PTFE, and the releasability of the toner is improved.

Hereinafter, the present invention will be described in detail with reference to examples. Parts in the examples are parts by weight.

[0062]

EXAMPLES (Example 1) 100 parts of a polyamide resin represented by the general formula (1) Conductive carbon black 7.0 parts Antioxidant 0.5 part The above composition was kneaded with a biaxial extrusion kneader. The additives were sufficiently and uniformly dispersed in the resin to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 2, and was extruded while adjusting the set temperature to a range of 240 to 260 ° C. to obtain a melt. Subsequently, the melt is guided to a cylindrical single-layer extrusion die 140 having a diameter of 100 mm and a die gap of 500 μm. After being extruded into a cylindrical shape, air is blown in from an air introduction path 150 to expand and expand. 180 as 140 mm in diameter,
The thickness was 150 μm. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electric resistance of the obtained intermediate transfer belt was 9.7 × 10 ⁷ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 5 times the minimum value of the measured value. In addition, the variation in the thickness measurement at the same position is 15
It was about 0 μm ± 10 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0064] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, there was no image density unevenness caused by uneven resistance of the belt from the beginning, and a good image free from color shift and image defect caused by elongation or breakage of the belt even after 50,000 sheets of durability was obtained. .

Example 2 Polyamide resin represented by the general formula (2): 100 parts Conductive carbon black: 7.0 parts Antioxidant: 0.5 part The above-mentioned composition was kneaded with a biaxial extrusion kneader. The additives were sufficiently and uniformly dispersed in the resin to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 2, and the melt was obtained by extruding while adjusting the set temperature to a range of 310 to 330 ° C. Subsequently, the melt is guided to a cylindrical single-layer extrusion die 140 having a diameter of 38 mm and a die gap of 800 μm, and is extruded into a cylindrical shape. 180 was set to 140 mm in diameter and 200 μm in thickness. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electric resistance of the obtained intermediate transfer belt was 3.6 × 10 ⁸ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about eight times the minimum value of the measured value. In addition, the variation of the thickness measurement at the same position is 20.
It was about 0 μm ± 10 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0067] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, there was no image density unevenness caused by uneven resistance of the belt from the beginning, and a good image free from color shift and image defect caused by elongation or breakage of the belt even after 50,000 sheets of durability was obtained. .

(Example 3) 100 parts of a polyamide resin represented by the general formula (2): conductive tin oxide 25.0 parts: antioxidant 0.5 part: The above composition was kneaded by a twin-screw extrusion kneader. The additives were sufficiently and uniformly dispersed in the resin to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 2, and the melt was obtained by extruding while adjusting the set temperature to a range of 310 to 330 ° C. Subsequently, the melt is guided to a cylindrical single-layer extrusion die 140 having a diameter of 32 mm and a die gap of 400 μm. After being extruded into a cylindrical shape, air is blown in from an air introduction passage 150 to expand and expand the final shape and dimensions. 180 was set to 140 mm in diameter and 60 μm in thickness. Further cut at a belt width of 230 mm,
An intermediate transfer belt 190 was obtained.

The electrical resistance of the obtained intermediate transfer belt was 7.5 × 10 ⁷ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 70 times the minimum value of the measured value. In addition, the variation in the thickness measurement at the same position is 6
It was about 0 μm ± 10 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0070] Further, the obtained intermediate transferring belt was mounted on a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, there was no image density unevenness caused by uneven resistance of the belt from the beginning, and a good image free from color shift and image defect caused by elongation or breakage of the belt even after 50,000 sheets of durability was obtained. .

Example 4 The same composition as in Example 1 was kneaded with a twin-screw extruder and kneader, and the additives were sufficiently and uniformly dispersed in the resin to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 3, and the melt was obtained by extruding while adjusting the set temperature to a range of 240 to 260 ° C. The melt is subsequently 250 m in diameter
m, and was guided to a cylindrical single-layer extrusion die 141 having a die gap of 600 μm and extruded into a cylindrical shape. Thereafter, the inner surface of the cylindrical molded product is brought into contact with the cooling mandrel 165,
While cooling, it was taken up at a take-up speed higher than the discharge speed of the extruder, to make the diameter 140 mm and the thickness 250 μm. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electrical resistance of the obtained intermediate transfer belt was 2.4 × 10 ⁸ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 60 times the minimum value of the measured value. In addition, the variation in the thickness measurement at the same position is 2
It was about 50 μm ± 15 μm. Also, when the obtained intermediate transfer belt surface was visually observed,
No foreign matter such as fish eyes and poor molding were observed.

[0073] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, there was no image density unevenness caused by uneven resistance of the belt from the beginning, and a good image free from color shift and image defect caused by elongation or breakage of the belt even after 50,000 sheets of durability was obtained. .

Example 5 The same composition as in Example 1 was kneaded with a twin-screw extruder and kneader, and the additives were sufficiently and uniformly dispersed in the resin to obtain a molding raw material. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 2, and was extruded while adjusting the set temperature to a range of 240 to 260 ° C. to obtain a melt. The melt is subsequently 30m in diameter
m, is guided to a cylindrical single-layer extrusion die 140 having a die gap of 400 μm, and is extruded into a cylindrical shape. Then, air is blown in from an air introduction path 150 to expand and expand. The final shape and dimensions 180 are 140 mm in diameter and 45 μm in thickness. And The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electric resistance of the obtained intermediate transfer belt was 8.3 × 10 ⁷ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 300 times the minimum value of the measured value. The variation in the thickness measurement at the same position was about 40 μm ± 6 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0076] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, although image density unevenness due to non-uniform resistance of the belt was extremely slight from the initial stage, it was determined that the image density was within a range in which there was no practical problem. Also,
After the 50,000-sheet running, very slight unevenness in image density as in the initial stage was observed, and at the same time, some color misregistration considered to be caused by the elongation of the intermediate transfer belt was observed.

Example 6 The same composition as in Example 2 was kneaded with a twin-screw extrusion kneader, and the additives were sufficiently and uniformly dispersed in the resin to obtain a molding raw material. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 3, and was extruded while adjusting the set temperature to a range of 310 to 330 ° C. to obtain a melt. The melt is subsequently 300 m in diameter
m and a die gap of 800 μm, and was guided to a cylindrical single-layer extrusion die 141 and extruded into a cylindrical shape. Thereafter, the inner surface of the cylindrical molded product is brought into contact with the cooling mandrel 165,
While cooling, it was taken up at a take-up speed higher than the discharge speed of the extruder, to make the diameter 140 mm and the thickness 320 μm. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electrical resistance of the obtained intermediate transfer belt was 5.1 × 10 ⁸ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 250 times the minimum value of the measured value. In addition, the variation in the thickness measurement at the same position was about 320 μm ± 15 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0079] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, although image density unevenness due to non-uniform resistance of the belt was extremely slight from the initial stage, it was determined that the image density was within a range in which there was no practical problem. Also,
Even after 50,000 sheets of durability, very slight unevenness in image density was confirmed as in the initial stage, and extremely slight cracks were observed at the end of the intermediate transfer belt. However, it was judged that the range was within a range in which there was no practical problem.

(Comparative Example 1) PET resin 100 parts Conductive carbon black 12.0 parts Antioxidant 0.5 parts The above composition was kneaded with a twin-screw extrusion kneader, and the additives were sufficiently homogenized in the resin. It was dispersed to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 3, and the melt was obtained by extruding while adjusting the set temperature to a range of 240 to 260 ° C. Subsequently, the melt was guided to a cylindrical single-layer extrusion die 141 having a diameter of 200 mm and a die gap of 400 μm, and was extruded into a cylindrical shape. Thereafter, the inner surface of the cylindrical molded product was brought into contact with the cooling mandrel 165, and was taken out while cooling at a take-up speed higher than the discharge speed of the extruder, to give a diameter of 140 mm and a thickness of 180 μm. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electric resistance of the obtained intermediate transfer belt was 5.2 × 10 ⁷ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was within 10 times the minimum value of the measured value. The variation in the thickness measurement at the same position was about 180 μm ± 10 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0082] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, good results were obtained without image density unevenness due to uneven resistance of the belt in the initial stage. However, when about 2,000 sheets were used, the endurance test was stopped because the intermediate transfer belt was broken.

(Comparative Example 2) Polyethylene resin 100 parts Conductive carbon black 10.0 parts Antioxidant 0.5 parts The above composition was kneaded with a twin-screw extruder, and the additives were sufficiently homogeneously mixed in the resin. It was dispersed to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 2, and was extruded while adjusting the set temperature to a range of 140 to 160 ° C. to obtain a melt. Subsequently, the melt is guided to a cylindrical single-layer extrusion die 140 having a diameter of 100 mm and a die gap of 500 μm. After being extruded into a cylindrical shape, air is blown in from an air introduction path 150 to expand and expand. 180 as 140 mm in diameter,
The thickness was 150 μm. The sheet was further cut at a belt width of 230 mm to obtain an intermediate transfer belt 190.

The electric resistance of the obtained intermediate transfer belt was 1.5 × 10 ⁸ Ω at an applied voltage of 100 V. Also, 1
The volume resistivity and the surface resistivity at the application of 00 V were measured at four locations in the circumferential direction and two locations in the axial direction at each location, for a total of eight locations, and the variation of the electrical resistance in the belt was measured. The maximum value of the measured value was about 1000 times or more the minimum value of the measured value. The variation in the thickness measurement at the same position was in the range of 150 μm ± 10 μm. Further, when the surface of the obtained intermediate transfer belt was visually observed, no foreign matters such as bumps and fish eyes and no molding defects were found.

[0085] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A print test of a full-color image was performed on paper, and then a durability test of 50,000 sheets was performed. As a result, remarkable image density unevenness considered to be caused by the non-uniformity of the belt resistance was confirmed from the initial stage, and it is considered that the image density unevenness was similar to the initial image unevenness even after 50,000 sheets of durability, and at the same time, was caused by the elongation of the intermediate transfer belt. Remarkable color shift was confirmed.

Comparative Example 3 The same composition as in Example 1 was kneaded with a twin-screw extruder and kneader, and the additives were sufficiently and uniformly dispersed in the resin to obtain a raw material for molding. This was further made into a kneaded product having a particle size of 1 to 2 mm. Next, the kneaded material was put into the hopper 120 of the single-screw extruder 100 shown in FIG. 3, and the melt was obtained by extruding while adjusting the set temperature to a range of 240 to 260 ° C. The melt is subsequently 140 m in diameter
m and a die gap of 150 μm were guided to a cylindrical single-layer extrusion die 141 and extruded into a cylindrical shape. Thereafter, the inner surface of the cylindrical molded product is brought into contact with the cooling mandrel 165,
While cooling, it was taken out at the same take-off speed as the discharge speed of the extruder to make the diameter 140 mm and the thickness 150 μm.
Further, the intermediate transfer belt 19 is cut at a belt width of 230 mm.
0 was obtained.

The electric resistance of the obtained intermediate transfer belt was 4.3 × 10 ⁷ Ω at an applied voltage of 100 V. Also, 10
The volume resistivity and surface resistivity at 0 V
Measurements were made at two locations in the axial direction at each location, a total of eight locations, and the variation in electrical resistance in the belt was measured. The maximum value of the measured values at eight locations was about 600 times the minimum value of the measured values. Met. In addition, the variation of the thickness measurement at the same position is 1
It was about 50 μm ± 50 μm. In addition, when the surface of the obtained intermediate transfer belt was visually observed, distortion and undulation considered to be due to instability of ejection during extrusion molding were confirmed.

[0088] Further, the obtained intermediate transfer belt is attached to a full-color electrophotographic apparatus shown in Figure 1, 80 g / m ²
A full color image was printed on paper. As a result, distortion and undulation of the surface of the intermediate transfer belt appeared in the image from the beginning. Further, since color misregistration considered to be caused by the thickness unevenness of the intermediate transfer belt was confirmed from the beginning, the durability test was not performed.

[0089]

According to the present invention as described above,
In an intermediate transfer member used in an image forming apparatus for transferring an image formed on a first image bearing member to an intermediate transfer member and further transferring the image onto a second image bearing member, an extruder and a ring are used for the molding material. The intermediate transfer belt is made of a polyamide having at least an aromatic ring in the main chain, obtained by melt-extrusion into a cylindrical shape using a die, and having a thickness smaller than the die gap of the annular die. The characteristics of the intermediate transfer belt are not changed even when the device is subjected to severe endurance use, and the effect of maintaining the same characteristics as in the initial stage can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a color image forming apparatus using a general electrophotographic process.

FIG. 2 is a schematic sectional view showing an example of a configuration of a molding apparatus applied to the present invention.

FIG. 3 is a schematic sectional view showing another example of the configuration of the molding apparatus applied to the present invention.

FIG. 4 is a partial perspective view showing a two-layer intermediate transfer belt of the present invention.

FIG. 5 shows an intermediate transfer belt having a three-layer structure according to the present invention;
(A) is a whole perspective view, (b) is a partial perspective view.

FIG. 6 is an explanatory diagram illustrating a method of measuring a resistance value of the intermediate transfer belt.

FIG. 7 is a schematic explanatory view showing measurement positions of a resistance value, a volume resistivity, and a surface resistivity of the belt-shaped transfer member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Primary charging device 3 Image exposure means 41 Yellow developing device 42 Magenta developing device 43 Cyan developing device 44 Black developing device 5 Intermediate transfer belt 6 Primary transfer roller 7 Secondary transfer roller 8 Secondary Transfer opposed roller 9 Cleaning member 10 Transfer material guide 11 Paper feed roller 12 Cleaning device 13 Fixer 14 Bias power supply 15 Power supply 100 Extruder 110 Extruder 120 Hopper 130 Hopper 140 Extrusion die 141 Extruded annular die 150 Gas introduction path 160 Cooling ring 165 Internal cooling mandrel 170 Dimensional stability guide 180 Shape dimensions 190 Intermediate transfer belt

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Minoru Shimojo 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akihiko Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Atsushi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akira Shimada 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. ( 72) Inventor Hidekazu Matsuda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H032 AA05 AA15 BA09 4F207 AA29 AB06 AB18 AG03 AG08 AG13 AG16 AH33 AH73 KA01 KA19 KL88

Claims (22)

[Claims] 1. An intermediate transfer member for use in an image forming apparatus for transferring an image formed on a first image carrier to an intermediate transfer member and further transferring the image onto a second image carrier. Is obtained by melt-extruding into a cylindrical shape using an extruder and an annular die, made of a polyamide having an aromatic ring in at least the main chain, and characterized in that the thickness is smaller than the die gap of the annular die. Intermediate transfer belt. 2. The diameter of said annular die is 5 mm.
2. The intermediate transfer belt according to claim 1, wherein the amount is 0 to 450%. 3. A gas having a pressure of at least atmospheric pressure is blown into a cylindrical melt discharged from an end of the annular die by an extruder so that the diameter of the molded product is 105 to 400% of the diameter of the annular die. The intermediate transfer belt according to claim 1, wherein the intermediate transfer belt is continuously formed while being expanded. 4. The polyamide having an aromatic ring in the main chain is a compound represented by the following general formula (1).
The intermediate transfer belt according to any one of claims 1 to 3. Embedded image 5. The polyamide having an aromatic ring in the main chain is a compound represented by the following general formula (2).
The intermediate transfer belt according to any one of the above items. Embedded image 6. A take-up speed of the molded product is higher than a discharge speed of a cylindrical melt discharged from an end of the annular die by an extruder.
14. The intermediate transfer belt according to item 13. 7. The intermediate transfer member having a resistance control agent content of 3
The intermediate transfer belt according to claim 1, wherein the content is 0% by weight or less. 8. The method according to claim 1, wherein the thickness is 45 to 300 μm.
The intermediate transfer belt according to any one of claims 1 to 7, wherein 9. The intermediate transfer belt according to claim 1, wherein the resistance value is 1 × 10 ³ to 1 × 10 ¹⁴ Ω. 10. The intermediate transfer belt according to claim 1, wherein the maximum value of the volume resistivity of each part is within 100 times the minimum value. 11. The intermediate transfer belt according to claim 1, wherein the maximum value of the surface resistivity of each portion is within 100 times the minimum value. 12. A method of manufacturing an intermediate transfer member used in an image forming apparatus for transferring an image formed on a first image carrier to an intermediate transfer member and further transferring the image on a second image carrier. Using an extruder and an annular die, a molding raw material comprising a polyamide having at least an aromatic ring in the main chain, the thickness is smaller than the die gap of the annular die, and the diameter is 50 to 450 with respect to the diameter of the annular die. %. 2. A method of manufacturing an intermediate transfer belt, comprising: melt-extruding into a cylindrical shape so as to obtain the intermediate transfer belt. 13. A method in which a gas having a pressure equal to or higher than the atmospheric pressure is blown into a cylindrical melt discharged from an end of the annular die by an extruder to expand the diameter of the annular die to 105 to 400% of the diameter of the annular die. The method of manufacturing an intermediate transfer belt according to claim 12, wherein the intermediate transfer belt is formed continuously. 14. The polyamide according to claim 1, wherein the polyamide having an aromatic ring in the main chain comprises a compound represented by the following general formula (1).
The method for manufacturing an intermediate transfer belt according to claim 2 or 13. Embedded image 15. The polyamide having an aromatic ring in the main chain is a compound represented by the following general formula (2).
The method for manufacturing an intermediate transfer belt according to claim 2 or 13. Embedded image 16. The intermediate according to claim 12, wherein a take-up speed of the molded product is higher than a discharge speed of a cylindrical melt discharged from an end of the annular die by an extruder. A method for manufacturing a transfer belt. 17. An image forming apparatus for transferring an image formed on a first image carrier to an intermediate transfer member and further transferring the image on a second image carrier, wherein the intermediate transfer member is formed by molding. A material obtained by melt-extruding a raw material into a cylindrical shape using an extruder and an annular die, made of a polyamide having an aromatic ring in at least a main chain, and having a thickness smaller than a die gap of the annular die. An image forming apparatus comprising: 18. The image forming apparatus according to claim 17, wherein the diameter of the intermediate transfer belt is 50 to 450% of the diameter of the annular die. 19. The intermediate transfer belt expands to 105 to 400% of the diameter of the annular die by blowing a gas above atmospheric pressure into the cylindrical melt discharged from the tip of the annular die by an extruder. The image forming apparatus according to claim 17, wherein the image forming apparatus is continuously formed while being formed. 20. The polyamide according to claim 1, wherein the polyamide having an aromatic ring in the main chain is a compound represented by the following general formula (1).
An image forming apparatus according to any one of claims 7 to 19. Embedded image 21. The polyamide according to claim 1, wherein the polyamide having an aromatic ring in the main chain comprises a compound represented by the following general formula (2).
An image forming apparatus according to any one of claims 7 to 19. Embedded image 22. The intermediate transfer belt according to claim 17, wherein the intermediate transfer belt is obtained from a molded product taken at a speed higher than a discharge speed of a cylindrical melt discharged from an end of the annular die by an extruder. 22. The image forming apparatus according to any one of 21.