JP2000181195A - Production of semiconductive roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a semiconductive roll having the uniform resistance value of a surface by subjecting the surface of the roll to melt coating with a semiconductive resin composition prepared by compounding resin coating carbon black with a thermoplastic resin, thereby forming a semiconductive layer. SOLUTION: The surface of the roll having core material of the strength necessary for holding the form as the roll is subjected to melt coating with the semiconductive resin composition prepared by compounding the resin coating carbon black with the thermoplastic resin, by which the semiconductor layer is formed. The resin coating carbon black preferably has a coating stabilization characteristic of >=1.1 in the value of A/B of B to A defined below, where A denotes the compounding ratio of the carbon black required for the specific volumetric resistivity of the composition obtained by compounding the carbon black of the same kind as the kind used for the resin coating carbon black to change to 1013 to 104 Ω/cm and B the compounding ratio of the carbon black required for the specific volumetric resistivity to change to the value described above, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductive roll, and more particularly, to a method suitable for a charging roll, a developing roll, a transfer roll, a fixing roll, an intermediate transfer drum and a transport drum of a copying machine. The present invention relates to a method for producing a semiconductive roll by melt extrusion molding used in the above.

[0002]

2. Description of the Related Art In recent years, semiconductive rolls have attracted attention in the fields of copying rolls, developing rolls, transfer rolls, fixing rolls, intermediate transfer drums, transport drums and the like of copiers and printers. 157721, JP-A-9-222788, etc.).

[0003] The above-mentioned semiconductive roll is provided with a semiconductive elastic layer made of a rubber composition mixed with carbon black on the surface of a core material having a strength necessary to maintain the form as a normal roll, If necessary, a resistance adjusting layer is provided on the surface thereof.

[0004] An example of a semiconductive roll used in an electrophotographic apparatus will be described with reference to the drawings with regard to an operating situation and its problems. FIG. 3 is a side view of the electrophotographic apparatus.
In FIG. 1, reference numeral 1 denotes a photosensitive drum as a member to be charged, and reference numeral 6 denotes a conductive belt as an intermediate transfer member. Around the photosensitive drum 1, a charging roll 2 as a charger, an exposure optical system 3 using a semiconductor laser or the like as a light source, a developing roll 4 to which toner is supplied to perform a developing function, and a cleaner 5 for removing residual toner And an electrophotographic process unit comprising the same.

Next, the operation will be described. First, the surface of the photosensitive drum 1 rotating in the direction of the arrow is uniformly charged by the charging roll 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device or the like (not shown) is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing roll 4. This toner image is transferred to a transfer roll 10
To transfer it to the conductive belt 6, and transfer it to the recording paper 11 between the transport roller 9 and the transfer roller 12.

As the charging roll and the transfer roll, a roller charging method, a roll transfer method, and the like have been developed to reduce the generation of ozone. (Japanese Unexamined Patent Publication No. 1-251818, 1-2)
As such a charging roll and a transfer roll, those having a conductive core material (metal shaft core) and a semiconductive elastic layer coated on the outer periphery thereof are used.

As a developing roll (semiconductive roll),
A configuration using a cylindrical thin layer developing tube (semiconductive layer) which has a longer peripheral length than the peripheral length of the drive roll on the surface layer and is provided on the drive roll has been proposed. A tube using a crystalline or amorphous nylon which is a thermoplastic resin has been proposed. (Japanese Unexamined Patent Publication No.
No. 8)

Further, as a method for producing such a semiconductive roll, Japanese Patent Application Laid-Open No. 3-59682 and Japanese Patent Application Laid-Open No. 5-2
Japanese Patent No. 48426 proposes a semiconductive roll for charging, transferring and developing a structure covered with a shrinkable and unshrinkable seamless tube having excellent surface properties.

[0009]

However, the conventionally proposed semiconductive roll has a problem that the resistance value on the surface thereof varies depending on the location and the resistance value is not uniform. As pointed out in the above-mentioned patents and the like, it is difficult to make the resistance value of the semiconductive region uniform over the whole area. Unevenness in the resistance value causes copy unevenness and white spots. Therefore, improvement has been desired.

[0010] In addition, since a shrinkable tube is generally used as a roll coating tube (semi-conductive tube), it is excessively shrunk by heat to cause wrinkles on the roll during shrinkage. It is very difficult to make a tube with a controlled resistance value because the tube is formed by molding, and a carbon chain is connected at the time of shrinkage, the resistance changes drastically, the electrical resistance can not be controlled, and the roll-coated tube As not suitable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a semiconductive roll having a uniform surface resistance. That is, the surface resistivity of the semiconductive roll is, for example, 10 ¹³ to 10 ⁴ Ω /.
An object of the present invention is to provide a method for producing a roll having a semiconductive layer in which the so-called semiconductive electric resistance in the range of □ is uniform and stabilized over the entire surface of the roll and has a wrinkle-free semiconductive layer on the roll surface.

[0012]

Means for Solving the Problems The present inventors have made various studies to achieve the above object, and as a result, have found that a specially processed carbon black is used as the carbon black blended in the semiconductive layer. It has been found that the above object can be achieved by coating a core material with a thermoplastic resin having semi-conductivity by melt extrusion.

The present invention has been completed based on the above findings, and the gist of the present invention is to provide a roll having a core material having a strength necessary for maintaining the form of the roll,
In a method for producing a roll having a semiconductive resin composition melt-coated, a semiconductive roll having a semiconductive layer formed by blending a resin coated carbon black with a thermoplastic resin and coating the semiconductive resin composition Lies in the manufacturing method.

Further, an embodiment in which the roll is provided with an elastic layer made of an elastic material around a core material, wherein the resin-coated carbon black has a value of B with respect to A defined below (B / A) of 1.1.
An embodiment having the above-described coating stabilizing characteristics is also one of the features of the present invention. A: Carbon black required for changing the volume resistivity of a composition obtained by blending the same type of carbon black used in the resin-coated carbon black with the vinyl chloride resin to 10 ¹³ to 10 ⁴ Ω · cm. Blending amount. B: The composition obtained by blending the resin-coated carbon black with the vinyl chloride resin has a volume resistivity value of 10 ¹³ to 10 ^4.
The amount of carbon black required to change to Ω · cm.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below in detail. The method for producing a semiconductive roll according to the present invention comprises coating the outer periphery of a core material with a molten resin.

(1) Core Material The core material may be any material as long as it has a strength necessary to maintain the form as a semiconductive roll. A shaft made of aluminum alloy, copper alloy or the like can be used.

(2) Roll Although the core material itself may be used as a roll, a material in which a layer of a synthetic resin or the like or an elastic layer described later is provided on the surface of the core material may be used as a roll.

(3) Thermoplastic resin The thermoplastic resin, which is the base resin for forming the semiconductive layer, is not restricted at all, and a material suitable for the purpose of use may be selected. Further, as long as the effects of the invention are not significantly impaired, additional components may be further added. For example,
Polypropylene, polyethylene, (high density, medium density, low density, linear low density), propylene ethylene block or random copolymer, polybutadiene, polyisobutylene, polyamide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, modified polyphenylene Ether, polyimide, liquid crystalline polyester,
Polysulfone, polyether sulfone, polyphenylene sulphite, polybisamide triazole, polyether imide, polyether ether ketone, polybutylene terephthalate, polyethylene terephthalate,
Polyvinyl fluoride, polyvinylidene fluoride, ethylene tetrafluoroethylene copolymer, chlorotrifluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether copolymer, acryl, alkyl acrylate copolymer, polyester ester copolymer, poly Either an ether ester copolymer, a polyether amide copolymer, a polyurethane copolymer or a mixture thereof is used.

(4) Resin-coated carbon black The resin-coated carbon black to be mixed with the thermoplastic resin as the base resin is as follows. The resin-coated carbon black itself has already been proposed and known by one of the present inventors (for example, see JP-A-9-717).
No. 33, No. 9-95625, No. 9-1249
No. 69). Since such carbon black is coated with a resin, the surface thereof has a certain degree of insulating properties, and has characteristics such as being excellent in dispersibility when blended with rubber or a synthetic resin.

FIG. 2 is a schematic explanatory view showing the relationship between the amount of carbon black blended in a vinyl chloride resin and the volume resistivity of the composition. As shown in FIG.
The volume resistivity decreases as the blending amount increases.

However, in the case of the composition (a) containing ordinary carbon black (that is, carbon black not coated with a resin), the resistance sharply decreases with an increase in the amount of the resin black, while the resistance of the resin coating increases. In the case of the composition (b) containing carbon black, the concentration gradually decreases. Therefore,
The resistance in the case of the composition (a) is determined not only by the absolute value of the resistance but also by various parts of the semiconductive layer due to slight differences in the dispersion state due to slight differences in the kneading conditions and molding conditions of the carbon black and slight variations in the compounding amount. Fluctuates greatly. On the other hand, in the case of the composition (b), the resistance value can be easily controlled by the compounding amount since the change (decrease) in the resistance value with the increase of the compounding amount is gentle, and the resin-coated carbon of the semiconductive layer is used. There is little change in resistance due to the difference in density of black, and a stable resistance can be obtained. In the present invention, the characteristics of the resin-coated carbon black as described above are referred to as coating stabilizing characteristics.

The magnitude of the above-mentioned coating stabilizing characteristics differs depending on the type of carbon black, the type of resin for coating, and the amount of coating. Therefore, in the present invention, a coating stabilizing property in which the value of B with respect to A (B / A) defined below is 1.1 or more, preferably 1.3 or more, and more preferably 1.5 or more is obtained. It is better to determine the above conditions as appropriate.

A: The composition obtained by blending the same type of carbon black used for the resin-coated carbon black with a vinyl chloride resin has a volume resistivity value of 10 ¹³ to 10.
^The amount of carbon black required to change to ⁴ Ω · cm.

B: The composition obtained by blending the resin-coated carbon black with the vinyl chloride resin has a volume resistivity value of 1
The amount of carbon black required to change from 0 ¹³ to 10 ⁴ Ω · cm.

The type of carbon black to be used is not particularly limited, and examples thereof include channel black, acetylene black, furnace black and the like. These can be used alone or in combination of two or more.

The DBP of the carbon black used is
The oil absorption is usually 40 to 250 ml / 100 g, preferably 45 to 150 ml / 100 g. When the DBP oil absorption is less than 40 ml / 100 g, the affinity between the resin to be coated and the carbon black is low, and a phenomenon in which the resin film is peeled off from the carbon black is observed. If the DBP oil absorption exceeds 250 ml / 100 g, the resin to be coated is absorbed too much into the carbon black, requiring a large amount of coating resin. The average primary particle size (particle size before resin coating) of the carbon black used is usually 10 to 300 nm, preferably 15 to 100 nm. If the particle size is too small, the conductivity and the dispersibility may decrease.

As the resin used for coating the carbon black, various resins described in JP-A-9-71733, JP-A-9-95625 and JP-A-9-124969 can be appropriately selected and used. . Preferably,
Thermosetting resin, in the melt extrusion molding described below,
When peeled from the carbon black, it does not decompose at the temperature during melt extrusion molding, and is durable enough to withstand melt-kneading by an extruder, that is, when the curable resin is applied to a glass surface and cured. It is desirable to have a pencil hardness of B or higher. Particularly, a polyfunctional epoxy resin described in JP-A-9-124969 is recommended.

Specific examples of the polyfunctional epoxy resin include glycidylamine type epoxy resins (“Sumiepoxy” ELM-100, 120, 434, etc., manufactured by Sumitomo Chemical Co., Ltd.), and triphenylglycidylmethane type epoxy resins (Yuika Shell Epoxy Co., Ltd.). "Epicoat" 1032H50, 1032
H60 etc.), tetraphenyl glycidyl methane type epoxy resin (“Epicoat” 103 manufactured by Yuka Shell Epoxy)
1), aminophenol type epoxy resin ("Epicoat" 154, 630, etc., manufactured by Yuka Shell Epoxy), diamide diphenylmethane type epoxy resin ("Epicoat" 604, manufactured by Yuka Shell Epoxy) etc., phenol novolak type epoxy resin ( Yuka Shell Epoxy “Epicoat” 152, etc.), orthocresol type epoxy resin (Yukaka Shell Epoxy “Epicoat” 180S65)
Etc.), bisphenol A novolak type epoxy resin (“Epicoat” 157S65, 1 manufactured by Yuka Shell Epoxy Co., Ltd.)
57S70). These epoxy resins are used together with a curing agent and a curing accelerator according to a conventional method.

The amount of the resin coated on the carbon black depends on the DBP oil absorption (oil absorption performance) of the carbon black used, but the DBP oil absorption is 40 to 250 ml / 1.
If it is 00 g, the ratio of the resin to the total amount of the carbon black and the resin (after curing and drying) is usually selected from the range of 5 to 40% by weight. If the amount of the resin is too small, the coating stabilizing property is not satisfied, and if the amount of the resin is too large, the insulating property becomes too large to use. As a coating method, for example, a method in which a water slurry of carbon black is contained in a container equipped with a screw type stirrer, and a resin solution is added little by little under stirring can be adopted. By such a treatment, the carbon black dispersed in the water migrates to the resin solution side and becomes particles of about 1 mm. Thereafter, draining is performed, and then the solvent and water are removed by vacuum drying, whereby a resin-coated carbon black can be obtained.

The amount of the resin-coated carbon black in the thermoplastic resin varies depending on the type of the raw material carbon black. When acetylene black is used as the raw material, 3 to 25 parts by weight is added to 100 parts by weight of the thermoplastic resin. It is preferable to use Ketjen Black as a raw material.
-10 parts by weight is preferred. If it is less than the above range, the conductivity is poor, and if it is more than the above range, the appearance of the product is deteriorated and the material strength is unfavorably reduced.

(5) Additional Component As an additional component, for example, one of epoxy, polyimide, polyamideimide, polymerimimide, melamine, phenol, unsaturated polyester or a mixture thereof as a thermosetting resin. Others include calcium carbonate, talc, mica, silica, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, zinc oxide, zeolite, wollastonite, diatomaceous earth, glass beads, bentonite, montmorillonite, asbestos, hollow glass spheres Filler such as graphite, molybdenum disulfide, titanium oxide, aluminum fiber, stainless steel fiber, brass fiber, aluminum powder, wood powder, rice hull, graphite, metal powder, conductive metal oxide, organometallic compound, organic metal salt, etc. Can be given.

Examples of the additives include antioxidants (phenol-based, sulfur-based, etc.), lubricants, various organic and inorganic pigments, ultraviolet absorbers, antistatic agents, dispersants, neutralizing agents,
Examples include a foaming agent, a plasticizer, a copper damage inhibitor, a cross-linking agent, and a flowability improver.

The above composition can be produced by using a usual kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a roll, a Brabender, a plastograph, or a kneader, if desired. Usually, each component is kneaded with an extruder or the like to form a compound in the form of a pellet, and then subjected to processing.However, it is also possible to directly supply each component to a molding machine and mold the composition while kneading the composition with a molding machine. it can.

(6) Elastic layer The elastic layer is usually provided on the surface of the core material to obtain a cushioning effect, and a conductive material such as carbon black may be blended into the elastic layer itself to form a semiconductive layer. Alternatively, a semiconductive layer may be provided on the elastic layer. The material of the elastic layer is not limited as long as it has elasticity. I should do it. For example, polyurethane, natural rubber, butyl rubber,
Typical materials include rubber-like materials such as nitrile rubber, polyisoprene rubber, polybutadiene rubber, silicone rubber, styrene-butadiene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, chloroprene rubber, and acrylic rubber, and mixtures thereof. . Usually, a vulcanizing agent, a vulcanizing aid, a softening agent and other additives are added to the rubber material for the elastic layer. The elastic layer may be formed on the surface of the core material by any means such as injection molding, press molding, and extrusion molding. Depending on the application, it can be used as a foam. Further, in order to impart semi-conductivity, it may be formed of a composition mixed with a conductive powder such as carbon black or metal powder. When the elastic layer itself is a semiconductive layer, it is more preferable to use a semiconductive resin composition in which a resin-coated carbon black is blended with a base resin.

(7) Manufacturing Method Although there is no particular limitation on the manufacturing method as long as it is a method of coating a molten resin, a preferred manufacturing apparatus will be described with reference to FIG. First, the molten resin 14 is kneaded by the extruder 13, fed into the die head 15, and pushed out of the die lip 17 from the die lip 17 through the manifold 16. At this time, the roll 18 is coated with the molten resin 14 extruded through the internal space of the die head 15 without bringing the roll 18 into contact with the die head 15. The position of the roll 18 is adjusted by adjusting the position of a retractor (not shown) disposed before and after the die. At this time, the distance between the roll 18 and the die head 15 is preferably about 2 to 10 mm. Further, in order to improve the adhesion and the roundness, the pressure is reduced through the reduced-pressure suction pipe 19, and the molten resin 14 is brought into close contact with the roll 18. Also,
The thickness adjustment of the molten resin 14 (the semiconductive layer 20) is performed by moving the die lip 17 with the lip adjustment bolt 21 and adjusting the gap between the die lip 17. Further, when ordinary carbon black (that is, carbon black not coated with a resin) is used, the distance between the roll 18 and the die head 15 is about 2 to 3 mm, and the adhesion and the roundness are improved. For this reason, when the pressure is reduced through the reduced-pressure intake pipe 19, the reduced pressure is not preferable from the viewpoint of resistance adjustment. However, the use of the resin-coated carbon has made it possible to expand the molding conditions.

Another coating apparatus described with reference to FIG. 1 is added, and an elastic layer such as a thermoplastic elastomer and a semiconductive layer obtained by blending a resin-coated carbon black with a thermoplastic resin and imparting semiconductivity are continuously formed. It can also be formed in an objective manner. Furthermore,
Depending on the material of the roll 18, if the roll 18 is a metal, the roll 18 is previously formed in order to increase the adhesion to the semiconductive layer 20.
May be subjected to a degreasing treatment (acid or alkali), a blast treatment or the like. Further, by pre-heating the surface of the roll 18, the adhesion can be improved. Also,
When the roll 18 is coated with a semiconductive layer, if the extrusion direction of the resin is the horizontal direction (horizontal direction), the resistance value slightly fluctuates due to a temperature difference between the upper and lower sides, the dripping of the molten resin due to gravity, and the like. , The vertical direction (almost vertical direction). Further, in order to disperse the variation in the thickness of the semiconductive layer and the uneven resistance, it is also a good method to coat while rotating the roll 18. By rotating the roll 18 in this manner, the extrusion direction of the semiconductive layer is displaced in a spiral shape with respect to the axial direction of the roll, so that unevenness due to thickness variation and extrusion can be dispersed. Generally, it is preferable to rotate in a fixed direction perpendicular to the axis. The amount of rotation is roll 18
Although it depends on the length, about 1/4 turn to 1 turn is sufficient from the start to the end of coating for one roll length (normally about 30 cm).

(8) Conductivity of Semiconductive Layer The preferable surface resistivity of the semiconductive roll is 1 ×
The range is 10 ¹³ to 10 ⁴ Ω / □. If the conductivity is too high (the resistance is too low), the applied voltage may leak. If the conductivity is too low (the resistance is too high), the conductive performance will be insufficient, and the conductive effect will not appear.

(9) Variation in Conductivity of Semi-Conducting Layer The range of variation in conductivity (surface resistivity) is preferably such that the maximum value of measured values (5 mm pitch in the circumferential direction) is within 10 times the minimum value. If it exceeds 10 times, the dispersion of the performance in the roll is undesirably large.

(10) Thickness of semiconductive layer The thickness of the semiconductive layer is different between the case where the elastic layer is provided and the case where it is not provided. When the elastic layer is not provided, the thickness is preferably 5 μm or more and 50 mm or less, more preferably 10 μm or more and 30 mm or less. Is more preferred. When the thickness is less than 5 μm, it becomes difficult to control the thickness when coating the molten resin film, and sometimes the film itself is ruptured, which is not preferable. On the other hand, if it exceeds 50 mm, the surface becomes thicker due to a thicker wall, resulting in poor roundness. When an elastic layer is provided, the thickness is preferably 5 μm or more and 1000 μm or less. When the thickness is less than 5 μm, it becomes difficult to control the thickness when coating the molten resin film, and sometimes the film itself is ruptured, which is not preferable. On the other hand, if the thickness exceeds 1000 μm, the semiconductive layer becomes hard, does not undergo elastic deformation and is not flexible, which is not preferable. When ordinary carbon black (ie, carbon black not coated with a resin) was used, the thickness of 20 μm or less was not preferable from the viewpoint of resistance adjustment. Until now. It is preferable that the elastic layer is blended with carbon black (including resin-coated carbon black) to make it semiconductive. The surface specific resistance value is preferably a resistance value close to the surface specific resistance value of the semiconductive layer on the surface. Usually, the average value is about 10 to 1/100 of the surface specific resistance value of the semiconductive layer. It is adjusted to the resistance value. From the viewpoint of stabilizing the surface resistivity of the semiconductive layer, it is desirable that the surface resistivity of the elastic layer be an average value and lower (higher conductivity) than the surface resistivity of the semiconductive layer. The value is set to be approximately (1/1) to about 1/100, preferably about 1/10 to 1/30.

(11) Diameter of semi-conductive roll The diameter of the semi-conductive roll is not restricted at all.
Usually, a diameter of about 5 mm to 40 mm is used for a member generally called a roll. For example, a charging roll, a developing roll,
A transfer roll and a fixing roll. In addition, diameter 100mm
About 250 mm is generally used for a member called a drum. For example, a transfer drum and a transport drum. The method for producing a semiconductive roll of the present invention makes use of the resistance stabilizing characteristic of a roll that is preferably used for a charging roll, a developing roll, a transfer roll, a fixing roll, a transfer drum, a transfer drum, and the like of a copying machine. It is a manufacturing method.

[0041]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

(1) Preparation of resin-coated carbon black Average primary particle diameter 40 nm, DBP oil absorption 65 ml / 10
A slurry was prepared by mixing 0 g of carbon black 540 g and pure water 1450 g at 6,000 rpm for 30 minutes using a homomixer. On the other hand, 60 g of "Epicoat 630" manufactured by Yuka Shell Epoxy was dissolved in 600 g of toluene to prepare an epoxy resin solution. Transfer the above slurry to a container equipped with a screw type stirrer, and
Under the stirring condition of m, the above epoxy resin solution was added little by little. After about 15 minutes, the entire amount of the carbon black dispersed in the water was transferred to the toluene side to become particles of about 1 mm. Next, after draining with a 60-mesh wire net, it was dried with a vacuum drier at 70 ° C. for 7 hours to remove water and toluene. The average residual toluene amount in the obtained resin-coated carbon black was 50 ppm, and the average residual water amount was 500 ppm. Further, the coating stabilizing properties (B / A) defined in the text of the resin-coated carbon black described above.
At 1 × 10 ⁷ Ω · cm, 23/18 = 1. 2
It was 8.

Examples 1 and 2 An average resistance value of 1 × 10 ⁷ Ω made of a composition in which carbon black (without resin coating) was mixed with urethane rubber on the outer periphery of a metal core having a diameter of 4 mm.
/ □ (maximum value 1 × 10 ⁸ Ω / □, minimum value 3 × 10 ⁶ Ω /
□) A roll having a diameter of 16 mm and having a conductive elastic layer was used. Rolls were extrusion coated with a semiconductive layer using the apparatus shown in FIG. Pass the roll through the center of the die head without contacting the die head, and once add the material having the formulation shown in Table 1 for 30 minutes.
The mixture was kneaded with an extruder having a diameter of mm to form pellets, and the pellets were extruded vertically from a 40 mm extruder connected to a die head to a film thickness of 50 μm, and coated on rolls.
The roll was rotated once every 300 mm. next,
The coated roll was cut into a length of 300 mm to form a transfer roller. Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. In the table, "air entrainment" refers to air remaining in the form of bubbles between the elastic layer and the semiconductive layer, and the presence or absence of the air was visually confirmed. When the obtained transfer roller was set in the apparatus shown in FIG. 3 and the image was evaluated, no image unevenness occurred.

[Comparative Example 1] As shown in Table 1, carbon black not coated with resin as a conductive filler (average primary particle diameter: 40 nm, DBP
Example 1 except that the oil absorption was changed to 65 ml / 100 g).
A transfer roll was obtained in the same manner as described above. Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. When the obtained transfer roll was set in the apparatus shown in FIG. 3 and the image was evaluated, image unevenness occurred.

Comparative Example 2 According to Example 2, carbon black as a conductive filler was changed to carbon black not coated with resin (average primary particle diameter 40 nm, DBP oil absorption 65 ml / 100 g), and without passing through a roll. The obtained seamless tube was extruded, and a contraction tube was manufactured using a stretching device. This was covered on the roll used in Example 1, heated at 150 ° C. and shrink-coated to obtain a transfer roll. Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. Although fine wrinkles were observed on the surface of the obtained transfer roll, the transfer roll was installed in the apparatus shown in FIG. 3 and the image was evaluated. As a result, image unevenness and wrinkle marks were generated.

[Examples 3 and 4] The same transfer rolls as in Examples 1 and 2 were used except that the diameter of the roll was changed from φ16 mm to φ120 mm and the die head of the extruder was changed to a large diameter. Obtained. Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. The obtained transfer roll was set as an intermediate transfer drum in place of the conductive belt in FIG. 3 and image evaluation was performed. As a result, no image unevenness occurred.

[Comparative Example 3] The materials having the composition shown in Table 1 were mixed and stirred by a side mill, and the obtained solution was mixed with an inner diameter of about 12%.
Using a centrifugal molding apparatus composed of a 0.25 mm cylindrical body, the temperature was gradually increased, and a cylindrical body (tube) was formed at 120 ° C. × 120 minutes with a cylinder rotation speed of 1000 rpm. The obtained tube is heated at a final temperature of 450 ° C.
Place in a hot air drier for 20 minutes to complete the dehydration polymerization reaction of the polyamic acid to a thickness of 100 μm and an inner diameter of 120.05 m
m and a seamless belt having a length of 300 mm were obtained. The obtained belt having a diameter of 120.05 mm was coated on the outer circumference of a metal tube having a diameter of 110 mm with an average surface resistivity of 1 × 10 ⁸ Ω / □ (maximum value 2 × 10 ⁹ Ω / □, a roller having a diameter of 120 mm and a conductive elastic layer (thickness: 5 mm) having a minimum value of 4 × 10 ⁶ Ω / □ was used as an intermediate transfer drum. Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. When the obtained transfer roll was set in the apparatus shown in FIG. 3 and the image was evaluated, image unevenness occurred. The cause is considered to be poor dispersion of carbon black.

[Comparative Example 4] The materials having the composition shown in Table 1 were mixed and stirred by a side mill, and the obtained solution was adjusted to an outer diameter of about 12 mm.
A seamless belt having a thickness of 100 μm, an inner diameter of 120.05 mm, and a length of 300 mm was obtained by applying the solution on a 0.05 mm aluminum cylindrical body, drying it, and extracting the cylindrical body. The obtained belt having a diameter of 120.05 mm was coated on the outer periphery of a metal tube having a diameter of 110 mm with an average surface resistivity of 1 × 10 comprising a composition obtained by mixing carbon into urethane rubber.
⁸ Ω / □ (maximum value 2 × 10 ⁹ Ω / □, minimum value 4 × 10 ⁶
(Ω / □) was mounted on a roll having a diameter of 120 mm having a conductive elastic layer by heat shrinkage to obtain an intermediate transfer drum.
Table 1 shows the physical properties of the semiconductive layer of the obtained transfer roller. When the obtained transfer roll was set in the apparatus shown in FIG. 1 and the image was evaluated, image unevenness occurred. The cause is considered to be poor dispersion of carbon black.

The materials used in the examples and comparative examples are as follows:
It is as follows. 1. Ethylene tetrafluoroethylene copolymer (manufactured by Asahi Glass Co., Ltd., trade name “Aflon COPC55AP 2. PBT (manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name“ Novadol 5020 ”) 3. PC (manufactured by Mitsubishi Engineering Plastics Co., Ltd., trade name“ Iupilon E2000 "4. Polyimide varnish (Ube Industries, Ltd., trade name" U Varnish-S ") 5. Vinylidene fluoride-tetrafluoroethylene copolymer (Daikin Co., Ltd., trade name" Neoflon ")

Experiments and evaluation methods in Examples and Comparative Examples are as follows. 1. Surface specific resistance (Ω / □) Using a resistance meter Hiresta HA probe (manufactured by Yuka Denshi Co., Ltd.), measurement was performed at a measuring voltage of 500 V and a measuring time of 10 seconds at a pitch of 5 mm in the circumferential direction of the semiconductive roll.

[0051]

[Table 1]

[0052]

The present invention relates to a method for producing a semiconductive roll in which a semiconductive layer containing resin-coated carbon black is formed on the surface of a core material, wherein the semiconductive layer has a surface resistivity of, for example, 10 ^13. The electric resistance of the so-called semiconductor region in the range of from 10 ⁴ Ω / □ to 10 ⁴ Ω / □ is stabilized, and a semi-conductive roll having no wrinkles on the surface is provided, and the practical value of the present invention is remarkable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of an apparatus used in the method of the present invention.

FIG. 2 is a schematic explanatory view showing the relationship between the amount of carbon black blended in a vinyl chloride resin and the volume resistivity of the composition.

FIG. 3 is a side view of a main part of an electrophotographic copying machine incorporating a semiconductive roll, obtained by the method of manufacturing a semiconductive roll according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 charging roll 3 exposure optical system 4 developing roll unit 5 cleaner 6 intermediate transfer belt 7 transport roll 8 transport roll 9 transport roll 10 transfer roll 11 recording paper 12 transfer roll 13 extruder 14 molten resin 15 die head 16 manifold 17 Between die lips 18 Core material 19 Decompression intake pipe 20 Resin film 21 Lip adjustment bolt 22 Die lip

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03G 15/16 G03G 15/16 3J103 15/20 15/20 4F213 (72) Inventor Makoto Morikoshi Yokkaichi, Mie Prefecture 1 Toho-cho, Yokohama-shi F-term in Yokkaichi Office of Mitsubishi Chemical Corporation (reference) 2H003 BB11 CC05 2H032 AA05 BA09 2H033 AA02 BB04 BB26 2H077 AD02 AD06 FA13 FA16 FA25 3F049 CA13 3J103 AA02 AA51 EA20 FA15 FA30 GA52 GA02 HA03 HA12 HA20 HA22 HA41 HA43 4F213 AA15 AA42 AA45 AB18 AD03 AD05 AD18 AG03 AG04 AH04 WA06 WA14 WA53 WA58 WB01 WB18

Claims (6)

[Claims] 1. A semi-conductive resin composition comprising a thermoplastic resin and a resin-coated carbon black is melt-coated on the surface of a roll having a core material having a strength necessary to maintain the form of the roll. A method for producing a semiconductive roll, characterized in that a semiconductive layer is formed by performing the method. 2. The method according to claim 1, wherein the roll is provided with an elastic layer made of an elastic material around a core material. 3. The method according to claim 1, wherein the roll is passed through an internal space of a die head having a ring-shaped extrusion port, and coated with a semiconductive resin composition extruded in a molten state from the die head. A method for producing the semiconductive roll according to the above. 4. The semiconductive material according to claim 1, wherein the resin-coated carbon black has a coating stabilizing property in which a value of B with respect to A (B / A) defined below is 1.1 or more. Roll manufacturing method. A: Carbon black required for changing the volume resistivity of a composition obtained by blending the same type of carbon black used in the resin-coated carbon black with the vinyl chloride resin to 10 ¹³ to 10 ⁴ Ω · cm. Blending amount. B: The composition obtained by blending the resin-coated carbon black with the vinyl chloride resin has a volume resistivity value of 10 ¹³ to 10 ^4.
The amount of carbon black required to change to Ω · cm. 5. The semiconductive layer has a volume resistivity of 10 ¹³ to 1
The method for producing a semiconductive roll according to any one of claims 1 to 4, wherein the maximum value and the minimum value are within 10 times at 0 ⁴ Ω · cm. 6. The method for producing a semiconductive roll according to claim 1, wherein the thickness of the semiconductive layer is 5 μm or more and 50 mm or less.