JP2002287528A - Semiconductive belt and method of manufacturing for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive belt which has high mechanical characteristics in spite of use for an image forming device and has the decreased intra-surface variations of resistance, the lessened degradation in resistance by an electrical load or lapse of time, good shape accuracy and lower surface friction resistance. SOLUTION: This semiconductive belt consists of a polyimide resin containing carbon black and the surface roughness Ra of the outer peripheral surface of the belt is <=0.5 μm and its coefficient of surface dynamic friction is <=0.8. This method of manufacturing the semiconductive belt includes a process step of supplying a polyamide acid solution uniformly dispersed with the carbon black to the inside surface of a cylindrical metal mold having the surface roughness Ra of <=1.0 μm and forming a film by rotating the cylindrical metal mold in its axial direction, a process step of peeling the cured film until the film can support itself by heating the metal mold and removing the solvent and a process step of replacing the peeled film to the outside surface of a metallic cylinder having the surface roughness Ra of 0.2 to 3.0 μm and heating the film together with the cylinder to effect the imide conversion thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductive belt used in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, and a multifunction peripheral thereof.
More specifically, the present invention relates to a semiconductive belt suitably used for an intermediate transfer unit, a transfer conveyance unit, a transfer fixing unit, and the like as a functional belt of the image forming apparatus.

[0002]

2. Description of the Related Art An intermediate transfer system using a seamless semiconductive belt has been conventionally known as an image forming system of a color electrophotographic system. In this method, a plurality of color toner images are transferred (primary transfer) onto a semiconductive belt, which is an intermediate transfer member, to obtain a full-color image on the intermediate transfer member. This is a method in which batch transfer (secondary transfer) is performed on a material. The intermediate transfer method is
Compared with the transfer drum system in which a transfer material is wound around a drum to perform transfer, there is an advantage that the transfer material is not selected. In recent years, in view of speeding up of image formation, a tandem transfer method in which a plurality of developing units are arranged side by side on an intermediate transfer member has been studied. This method is different from the above-mentioned intermediate transfer method.
It is not necessary to form an image on the intermediate transfer body for each color, and the image can be formed while the transfer belt is rotated once.

In an image forming apparatus using such a transfer method using a semiconductive belt, toner remains on the transfer belt after the secondary transfer, and the remaining toner is removed before forming the next image. A cleaning step is required, and a method using a cleaning blade is generally adopted for this step. In the transfer method using the cleaning blade, the surface property of the transfer belt causes problems such as image defects and blade turning.

[0004] JP-A-2000-206798 discloses that
There has been proposed a transfer transfer body and an image forming apparatus that can suppress turning of a cleaning blade and occurrence of image defects by forming protrusions by a filler on an image bearing surface of the transfer transfer body. However, such protrusions of the transfer carrier cause a variation in the resistance value. Particularly, when the protrusions are formed by carbon black particles, which are conductive fine powders to be added, an excessive current is concentrated on the protrusions. This may cause a reduction in belt resistance.

[0005] As a belt used for such an application, a belt made of a rubber material is known. However, a semiconductive belt made of a rubber material has difficulty in achieving uniform resistance of the conductive fine powder, so it is difficult to develop a resistance value with little variation, and the surface tends to be rough, and the friction resistance value is low. high. For this reason, when a semiconductive belt made of a rubber material is used in an image forming apparatus, the blade for cleaning the toner remaining on the belt is likely to be turned up or to be worn out. Frequent operation and shortens the life of the apparatus. In addition, the semiconductive belt made of a rubber material is likely to expand and contract due to its elasticity, particularly when used for a tandem type transfer conveyance belt or an intermediate transfer belt having a diameter larger than that of a conventional belt. There was a problem with the positioning accuracy and it was not practical.

[0006] Japanese Patent No. 2560727 and Japanese Patent Laid-Open No. 5-77
No. 252 proposes a seamless belt using a thermosetting polyimide resin containing a conductive substance. However, these documents mention improvement in resistance variation and mechanical characteristics, but do not mention any surface friction coefficient or belt shape accuracy.

On the other hand, JP-A-7-156287 and JP-A-2000-271946 disclose a manufacturing method in which a molded body removed from the inner peripheral surface of a cylinder is inserted by inserting or shrinking a rod. ing. However, these examples do not mention the coefficient of friction of the outer peripheral surface of the belt.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus which has high mechanical properties, has small in-plane variation in resistance, and has a low resistance due to electrical load and aging. An object of the present invention is to provide a semiconductive belt which has a small reduction, good shape accuracy, and low surface friction resistance, and a method for manufacturing the same.

[0009]

The above object can be achieved by the present invention as described below. That is, the semiconductive belt of the present invention is a semiconductive belt made of a polyimide resin containing carbon black,
The surface roughness Ra according to IS B0601 (1994) is 0.5 μm or less, and the surface dynamic friction coefficient is 0.8 or less.

The surface roughness Ra of the outer peripheral surface of the belt is 0.5 μm or less, preferably 0.3 μm or less, from the viewpoint of suppressing image defects and turning of the cleaning blade when used as a transfer belt in an image forming apparatus. More preferably, it is 0.25 μm or less.

The surface roughness Ra of the outer peripheral surface of the belt is JI
It is a value measured by the method shown in the example according to SB0601 (1994).

The surface dynamic friction coefficient is 0.8 or less, more preferably 0.7 or less, from the viewpoint of rubbing with the cleaning blade or suppressing the turning of the cleaning blade.

The surface dynamic friction coefficient is a value measured by the method shown in the embodiment.

As the carbon black contained in the semiconductive belt of the present invention, commercially available products can be suitably used, and examples thereof include channel black and furnace black. Furnace black is improved in dispersibility in solvent by using an oxidized one,
It is preferable that the carbon black is appropriately oxidized, and the carbon black is channel black or furnace black that is oxidized.

In the semiconductive belt of the present invention, the carbon black contained in the polyimide resin preferably does not substantially contain particles having a particle diameter of 0.5 μm or more, and particles having a particle diameter of 0.3 μm or more are preferably used. It is more preferred not to include particles of a diameter. Here, the particle diameter refers to the particle diameter of the aggregated primary particles, and is a value measured by SEM (scanning electron microscope) or TEM (transmission electron microscope).

Since the semiconductive belt of the present invention is used as a transfer belt in an image forming apparatus, the common logarithmic value of the surface resistivity of the outer peripheral surface of the belt is 9-13.
(LogΩ / □), more preferably 10 to 13 (logΩ / □).

The difference between the maximum value and the minimum value of the common logarithmic value of the surface resistivity is 1.0 (lo) to suppress image defects.
gΩ / □), and more preferably 0.8 (logΩ / □).

The surface resistivity is a value measured by the method shown in the examples.

In the semiconductive belt according to the present invention, the content of the carbon black is preferably 5 to 30% by weight, more preferably 10 to 30% by weight, based on the solid content of the polyimide resin. It is. If the content is less than 5%, it is difficult to obtain a desired resistance as a semiconductive belt, and it is difficult to obtain stability of the resistance. Also, 3
If it exceeds 0% by weight, the effect on the surface properties of the belt increases, and the belt itself tends to become brittle.

The method for producing a semiconductive belt of the present invention is a method suitably used for producing the semiconductive belt of the present invention. That is, in the manufacturing method, a polyamic acid solution in which carbon black is uniformly dispersed is supplied to the inner surface of a cylindrical mold having a surface roughness Ra of 1.0 μm or less, and the cylindrical mold is moved in the axial direction. A step of forming a film by rotating, a step of heating the formed mold, removing a solvent, and peeling the cured film until it can support itself, and a step of removing the peeled film to a surface roughness Ra of 0. 2-3.
The method is characterized by including a step of replacing the outer surface of a metal cylinder having a diameter of μm, heating the entire cylinder, and performing imide conversion.

The surface roughness Ra of the cylindrical mold is 1.0 μm or less, preferably 0.8 μm, in order to prevent irregularities on the mold surface from affecting the surface properties of the outer or inner surface of the belt.
μm or less, and more preferably 0.7 μm or less.

The surface roughness Ra of the metal cylinder is such that the residual solvent and ring-closing water that evaporate during heating do not stay between the cylinder and the belt, and irregularities on the cylinder surface affect the surface properties of the inner or outer surface of the belt. 0.2-3.
0 μm, and more preferably 0.5 to 2.5 μm.

The surface roughness Ra is a value measured by the method shown in the examples.

[Effects] The semiconductive belt of the present invention comprises:
Since the surface roughness Ra and the surface kinetic friction coefficient are within predetermined ranges, the shape accuracy is good and the surface friction resistance is small, so that it can be suitably used as a transfer belt or the like in an image forming apparatus.

In the semiconductive belt of the present invention, carbon black is less agglomerated, and the surface resistivity of the outer peripheral surface of the belt is within a predetermined range. It has a small variation, a small resistance value, and a small decrease in resistance with time, and can be suitably used as a transfer belt or the like in an image forming apparatus.

According to the method for producing a semiconductive belt of the present invention, a semiconductive belt suitable as a transfer belt or the like in an image forming apparatus can be produced.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The semiconductive belt according to the present invention is a semiconductive belt having a polyimide resin layer in which carbon black is uniformly dispersed as conductive fine powder on at least a surface layer, and is a single layer. May have two or more layers. As a carbon black, when contained in a polyimide resin, substantially 0.5 μm is used.
m does not contain particles having a particle size of at least m,
It is more preferred that the particles do not contain particles having a particle diameter of 0.3 μm or more.

Generally, the primary particle diameter of carbon black is from 10 nm to 1 μm. However, when the carbon black is mixed in a dispersion liquid or a resin, aggregation may occur when the carbon black is dispersed. In the present invention, when the particle size of carbon black dispersed in the polyimide resin as the semiconductive belt is 0.5 μm or more, the carbon particles having a large particle size existing in the surface layer during the manufacturing process of the semiconductive belt are used. The black becomes projections on the belt surface, which may cause deterioration of the surface accuracy, uneven resistance, and further decrease in resistance due to electric load of the semiconductive belt.

As the carbon black, channel black or furnace black is preferable. Furnace black, which has been subjected to an oxidizing treatment, is preferably used since it is improved in dispersibility in a solvent when it is subjected to an oxidizing treatment. Furnace black that has been subjected to oxidation treatment has a functional group containing oxygen (carboxyl group, ketone group, lactone group,
Since a hydroxyl group or the like is provided, the carbon black surface has a good affinity with a polar solvent, and the surface of carbon black is less susceptible to oxidative deterioration due to an electric load or the like. When such carbon black is used for a semiconductive belt, formation of a conductive path hardly occurs, and a decrease in resistance can be prevented.

The channel black used in the present invention includes color black FW200, color black FW2, color black 2V, color black FW1, color black FW18, special black 6, color black S170, and color black S16 manufactured by Degussa Corporation.
0, Special Black 5, Special Black 4, Special Black 4A, PRINTEX 150T, PRINTEX U, PRINTEX V, PRINTEX 14
0U, PRINTEX 140V, etc., and examples of furnace black that has been oxidized include special black 550, special black 350, special black 250, special black 100 manufactured by Degussa Corporation, and MA100, MA100R, MA100S, M100M manufactured by Mitsubishi Chemical Corporation.
A11, MA230, MA220, MA7, MA8, M
A77, MONARCH1000, MO manufactured by Cabot Corporation
NARCH1400, MONARCH1300, MOG
UL-L, REGAL400R, and the like.

In the present invention, a semiconductive belt is prepared by dispersing the above carbon black in a polyimide resin.
As a raw material of the polyimide resin, a polyamic acid solution obtained by polymerizing tetracarboxylic dianhydride or a derivative thereof and a diamine in a solvent can be used. The polyamic acid is usually obtained in the form of a solution by reacting substantially equimolar amounts of a tetracarboxylic dianhydride or a derivative thereof and a diamine in an organic solvent.

Examples of suitable tetracarboxylic dianhydrides or derivatives thereof include pyromellitic dianhydride, 3,
3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3 ', 4-biphenyltetracarboxylic dianhydride 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, , 2'-bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-
3,4,9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
And ethylene tetracarboxylic dianhydride.

On the other hand, examples of diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane,
3,3′-dichlorobenzidine, 4,4′-diaminodiphenylsulfide, 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl- 4,4′-biphenyldiamine, benzidine,
3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylpropane, 2,4-
Bis (β-amino-t-butyl) toluene, bis (p-
β-amino-t-butylphenyl) ether, bis (p
-Β-methyl-δ-aminophenyl) benzene, bis-
p- (1,1-dimethyl-5-amino-bentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (p-aminocyclohexyl) ) Methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diamino Dodecane, 1,2-
Bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-
Methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,17-diaminoeicosadecane, 1,
4-diaminocyclohexane, 1,10-diamino-
1,10-dimethyldecane, 1,12-diaminooctadecane, 2,2-bis [4- (4-aminophenoxy)
Phenyl] propane, piperazine, H ₂ N (CH ₂ ) ₃
O (CH ₂ ) ₂ O (CH ₂ ) NH ₂ , H ₂ N (CH ₂ )
₃ S (CH ₂ ) ₃ NH ₂ , H ₂ N (CH ₂ ) ₃ N (CH
₃ ) ₂ (CH ₂ ) ₃ NH _{2 and the} like.

As the solvent for the polymerization reaction of the tetracarboxylic dianhydride and the diamine, a polar solvent is preferably mentioned from the viewpoint of solubility and the like. N, N-
Dialkylamides are preferred, specifically, for example,
N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-diethylacetamide,
N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphortriamide, N-methyl-
2-pyrrolidone, pyridine, tetramethylene sulfone,
Dimethyltetramethylene sulfone and the like. These can be used alone or in combination.

Hereinafter, the method for producing a semiconductive belt according to the present invention comprises the steps of (a) producing a polyamic acid solution in which carbon black is uniformly dispersed, and (b) supplying the polyamic acid solution to the inner surface of a cylindrical mold. (C) heating the molded mold, removing the solvent, and peeling off the cured film until it can support itself; (d) ) The exfoliated film is replaced with the outer surface of a metal cylinder, and the entire cylinder is heated and subjected to imide conversion. The details will be described below.

(A) In order to obtain a polyamic acid solution in which carbon black is uniformly dispersed, the carbon black is dispersed in the polar solvent in advance, and then the acid anhydride component and the diamine component are mixed, followed by a polymerization reaction. Or a method of obtaining a polyamic acid solution by mixing an acid anhydride component and a diamine component in the polar solvent, and performing a polymerization reaction to obtain a polyamic acid solution, and then mixing the carbon black or a dispersion liquid in which the carbon black is dispersed. And the like. Examples of the method of dispersing carbon black in a polar solvent include a method using various dispersing devices such as a ball mill and a basket mill, and a method of dispersing with an ultrasonic wave. As a method of mixing and dispersing carbon black in a polyamic acid solution,
A method of mixing and dispersing with a planetary mixer, a bead mill, a three-roll mill or the like can be used. At this time, a polymer dispersant may be used in order to increase the affinity between the carbon black and the solvent and to disperse the carbon black more uniformly. As a specific example, poly (N-vinyl-2-pyrrolidone) , Poly (N, N'-diethylacrylazide),
Poly (N-vinylformamide), Poly (N-vinylacetamide), Poly (N-vinylphthalamide), Poly (N-vinylsuccinamide), Poly (N-vinylurea), Poly (N-vinylpiperidone), Poly (N-vinylcaprolactam), poly (N-vinyloxazolidone) and the like. At this time, a silicone-based or fluorine-based organic compound, a coupling agent, a lubricant, an antioxidant, and other additives may be contained to the extent that the object of the present invention is not impaired, and other polymer components may be copolymerized. Or may be blended.

Whether or not the carbon black is uniformly dispersed is confirmed by a method such as visually confirming with a transmission microscope or the like.

As described above, the content of carbon black is set to 5 to 30% by weight, more preferably 10 to 30% by weight, based on the solid content of the polyimide resin.

The viscosity of the polyamic acid solution in which carbon black is dispersed is 0.01 to 1000 Pa · s, more preferably 0.1 to 500 Pa · s. 0.01
When it is less than Pa · s, it is difficult to increase the thickness of the film, and it is necessary to perform supply molding several times. Therefore, not only the number of steps is increased, the manufacturing cost is increased, but also the thickness accuracy and the like tend to decrease. 10
If it exceeds 00 Pa · s, the handling property of the polyamic acid solution is poor, and there is a possibility that supply and molding of the following polyamic acid may be hindered.

(B) The thus obtained carbon black-dispersed polyamic acid solution is supplied to the inner surface of a cylindrical mold. The surface roughness Ra of the inner peripheral surface of the cylindrical mold used at this time is 1.0 μm or less, and more preferably 0.8 μm or less. Examples of the supply method include a method using a die, a method using a dispenser, and a method of supplying in a spray form, and can be selected according to properties such as the viscosity of the polyamic acid solution.

In order to form the supplied polyamic acid solution into a uniform film, a cylindrical mold is rotated in the axial direction and molded.
At this time, the cylindrical mold and the film may be molded while heating for the purpose of removing the solvent, decreasing the viscosity, and the like.

(C) Subsequently, the cylindrical mold after molding is heated to remove the solvent, and is cured until it can be supported as a polyamic acid belt-shaped member, and then peeled from the mold. The heating conditions at this time are within the scope of the present invention,
There is no particular limitation as long as the belt-shaped member can be quickly heated and cured, but the heating temperature is 100 to 250 ° C.
The heating time is preferably about 0.2 to 5 hours. In the present invention, the residual ratio of the solvent at this time is preferably low, and 50% by weight based on the solvent weight of the polyamic acid solution.
The following is preferred.

A known method can be used for peeling from the mold. For example, there is a method in which air is pressure-fed to a minute through hole provided in advance in a peripheral wall of the end of the mold. A release material layer made of a silicone resin or the like may be formed in advance on the inner surface of the cylindrical mold so as to be easily separated from the mold.

In the case of the polyimide resin used in the present invention, when the polyimide resin is held on the inner surface of the mold until after the imidization, the holding property of the cylindrical shape is good, but the film cannot be released from the inner surface of the mold. It can be difficult. A method of peeling the resin by peeling a part of the mold from an edge of a cutter blade or the like is considered, but there is a problem that the inner surface of the mold is damaged. On the other hand, a method in which the release material layer as described above is formed on the inner surface of the mold, and it is easy to remove the mold and perform imidization is also considered. It may be difficult to maintain a good shape of the belt cylinder due to the whole or partial peeling. Therefore, in the present invention, the following steps are adopted through a step of peeling off from the mold before the completion of the imide conversion.

(D) Subsequently, the peeled belt-like member is replaced with the outer surface of a metal cylinder, and the cylinder is heated and imide-converted, and then cooled to room temperature.
As the material of the metal cylinder, in order to finally determine the shape of the semiconductive belt, it is necessary that the thermal expansion coefficient is larger than the belt material, and specific examples thereof include copper, aluminum, and stainless steel. Can be The surface roughness Ra of the outer surface of the metal cylinder is 0.2 to 3.0 μm, more preferably 0.2 to 2.5 μm. Surface roughness 0.2
If it is less than μm, residual solvent and ring-closing water generated at the time of ring closure during imide conversion are confined between the belt inner surface and the metal cylinder, and not only the surface property of the belt inner peripheral surface becomes non-uniform but also Swelling and the like. When the surface roughness exceeds 3.0 μm, the evaporation solvent is preferably diffused, but the roughness of the cylinder surface tends to be transferred to the inner surface and the outer surface of the semiconductive belt. The heating conditions at this time are not particularly limited as long as the imide conversion can be performed quickly, but the heating temperature is not lower than the heating temperature of the cylindrical mold and not higher than 450 ° C., and the heating time is about 0.5 to 5 hours.

The belt thus obtained is taken out of the cylinder. Normally, it may be taken out after cooling to room temperature and heat shrinkage of the cylinder.

According to the manufacturing method of the present invention, the outer surface of the belt has the accuracy transferred from the inner peripheral surface of the mold, and the inner surface of the belt comes into contact with the cylinder which has been replaced once in the heating step, thereby forming the cylindrical shape of the belt. Can be obtained.

The semiconductive belt of the present invention not only suppresses the occurrence of the turning of the cleaning blade, but also has no protrusion due to the aggregation of carbon, and the fluctuation of the surface resistance is minimized.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and the like specifically showing the configuration and effects of the present invention will be described below.

Example 1 PRINTEX dried in 726 g of N-methyl-2-pyrrolidone (hereinafter, NMP)
35 g (24% by weight based on the solid content of the polyimide resin) of V (manufactured by Degussa, average particle size 25 nm, unoxidized channel black) was added, and mixed at room temperature for 8 hours by a ball mill. In this carbon black-dispersed NMP solution, 118 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 43 g of p-phenylenediamine were dissolved, and the polymerization reaction was carried out under a nitrogen atmosphere while stirring at room temperature for 6 hours. Thus, a polyamic acid solution containing carbon black (solid content: 20% by weight, viscosity: 200 Pa · s) was obtained.

This polyamic acid solution was mirror-finished to an inner surface having a surface roughness Ra of 0.2 μm and an inner diameter of 300 m.
m, applied to the inner surface of a cylindrical mold having a length of 500 mm through a dispenser to a thickness of 400 μm, and
m for 15 minutes to form a coating layer having a uniform film thickness, while rotating at 250 rpm, applying hot air of 60 ° C. from the outside of the mold for 30 minutes, heating at 150 ° C. for 60 minutes, and then reaching room temperature. Cool. The polyamic acid belt cured until it can be self-supported from the inner surface of the mold is peeled off by sending air to the end of the belt, and the surface roughness Ra
After replacing the outer surface of a 1.8 μm metal cylinder,
After the temperature was raised to 360 ° C. at a rate of 3 ° C./min, the temperature was maintained at 360 ° C. for 30 minutes to remove dehydrated ring-closing water and complete the imide conversion reaction. Thereafter, the resultant was cooled to room temperature to obtain a desired semiconductive belt having a thickness of 76 μm.

[Embodiment 2] PRINT in Embodiment 1
Instead of EX V, SPECIAL BLACK 2
50 (manufactured by Degussa, average particle size 56 nm, oxidized furnace black) in the same manner as described above.
A 5 μm semiconductive belt was produced.

Comparative Example 1 PRINT in Example 1
A semiconductive belt having a thickness of 76 μm was produced in the same manner except that PRINTEX 55 (manufactured by Degussa, average particle diameter 25 nm, unoxidized furnace black) was used instead of EXV.

Comparative Example 2 A semiconductive belt having a thickness of 74 μm was produced in the same manner as in Example 1, except that the surface roughness Ra of the inner surface of the cylindrical mold was changed to 2.5 μm.

Comparative Example 3 A semiconductive belt of 77 μm was produced in the same manner as in Example 1, except that the surface roughness Ra of the metal cylinder surface was changed to 3.2 μm.

Comparative Example 4 The metal cylinder surface in Example 1 was mirror-finished, and the surface roughness Ra was 0.1 μm.
A semiconductive belt having a thickness of 76 μm was prepared in the same manner, except that On the inner peripheral surface of the semiconductive belt, traces which are considered to be due to evaporation of dehydrated ring-closing water and the like were left.

(Evaluation Method) Surface roughness (Ra) According to JIS B 0601, samples are taken from any eight points on the belt, and the circumferential direction thereof is cut off by a surface roughness meter (Surfcom 554A (manufactured by Tokyo Seimitsu Co., Ltd.)) at 0.32 mm. , Measuring length 2.5mm, driving speed 0.1
The measurement was performed at 2 mm / sec and a stylus load of 70 mg, and the average value was determined.

The surface roughness (Ra) of the inner surface of the cylindrical mold and the surface of the metal cylinder is as follows: cutoff 4 mm, measurement length 20 mm, drive speed 1.5 mm / sec, stylus load 70
The measurement was performed in mg, and the average value was determined.

2. Coefficient of surface kinetic friction Sampling was performed at any eight points on the belt, and in the circumferential direction of each belt, a reciprocating kinetic friction tester (AFT-15B manufactured by Orientec Co., Ltd.) using a steel ball of φ10 mm, a test load of 200 g and a test speed of 150 mm / Min. The dynamic friction coefficient was measured under the above conditions, and the average value was determined.

3. Agglomerated particle size of carbon black The obtained belt is cut with a microtome, and
Observation was made with an EM (scanning microscope). A sample that did not contain an aggregated particle diameter of 0.5 μm or more was evaluated as ○, and a sample that included an aggregated particle size was evaluated as X.

4. Surface resistivity and its variation Hiresta IP, MCP-HT260 (Mitsubishi Yuka,
After one minute with an applied voltage of 100 V using a probe (HR-100), the surface resistivity was measured at 25 ° C. and 60% RH under measurement conditions. The measurement was performed at 12 points on the outer peripheral surface of the belt, the average value was defined as the surface resistivity of the belt, and the difference between the maximum value and the minimum value was defined as the variation.

[0062] 5. Image / Belt Drivability The obtained semiconductive belt is incorporated into an actual copying machine as a tandem-type intermediate transfer belt, and is 5,000 sheets of plain paper.
An image forming test was performed on one sheet.も の: good image and belt driveability, Δ: slight image defect or poor driveability, ×: image defect visually recognizable or drive defective.

6. Cleaning performance: A sample showing good cleaning performance through the image forming test of 5 above was evaluated as ○, a toner remaining was observed as Δ, and a cleaning blade turned up was evaluated as ×.
And

[0064]

[Table 1] Table 1 shows that the semiconductive belt of the example product has a surface roughness Ra
And the coefficient of surface dynamic friction was small, and the variation in surface resistivity was small. When such a semiconductive belt is used in a copying machine, good cleaning properties can be obtained while preventing the cleaning blade from being turned up, and the transfer of the transfer object and the toner image can be performed with high accuracy, and high-quality images can be obtained. The formation can take place. On the other hand, the semiconductive belt of the comparative example caused problems in image formation and belt driveability, and was inferior in cleaning performance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/04 C08K 3/04 4F205 C08L 79/08 C08L 79/08 Z 4J002 G03G 15/20 102 G03G 15 / 20 102 15/24 15/24 // B29K 79:00 B29K 79:00 103: 04 103: 04 B29L 29:00 B29L 29:00 (72) Inventor Toshiaki Iwamoto 1-1-2 Shimohozumi, Ibaraki-shi, Osaka No. Nitto Denko F-term (reference) 2H033 AA23 BA12 BB01 BE09 2H078 AA21 BB01 BB12 CC06 DD51 DD57 FF04 FF09 2H200 FA02 GB22 GB40 JA07 JA08 JB06 JB45 JB46 JB47 JC03 JC15 JC16 JC17 MA04 MA06 AF02 MB03 AF02 AH19 BA02 BB02 BC01 BC08 BC16 BC17 4F202 AA40 AB18 AG16 CA04 CB01 CL04 CN01 CN05 4F205 AA40 AB18 AG16 GA02 GA06 GB01 GC04 GE16 GE22 GE24 GF22 GF24 GN01 GN13 GN21 GW06 GW15 GW23 4J002 CM041 DA036 FD116 GM01

Claims (6)

[Claims] 1. A semiconductive belt made of a polyimide resin containing carbon black, wherein the outer peripheral surface of the belt has a surface roughness Ra according to JIS B0601 (1994).
Is a semiconductive belt having a surface dynamic friction coefficient of 0.5 μm or less and a surface dynamic friction coefficient of 0.8 or less. 2. The semiconductive belt according to claim 1, wherein the carbon black contained in the polyimide resin does not substantially contain particles having a particle diameter of 0.5 μm or more. 3. The common logarithmic value of the surface resistivity of the outer peripheral surface of the belt is 9 to 13 (logΩ / □), and the difference between the maximum value and the minimum value is within 1.0 (logΩ / □). The semiconductive belt according to claim 1. 4. The semiconductive belt according to claim 1, wherein the content of the carbon black is 5 to 30% by weight based on the solid content of the polyimide resin. 5. The semiconductive belt according to claim 1, wherein the carbon black is channel black or oxidized furnace black. 6. A polyamic acid solution in which carbon black is uniformly dispersed is supplied to the inner surface of a cylindrical mold having a surface roughness Ra of 1.0 μm or less, and the cylindrical mold is rotated in its axial direction. Forming the film, heating the mold after the molding, removing the solvent, and peeling off the cured film until it can support itself, and the surface roughness Ra of the peeled film is 0.2. A method for producing a semiconductive belt, comprising the steps of: replacing the outer surface of a metal cylinder having a thickness of about 3.0 μm, heating the entire cylinder, and performing imide conversion.