JP2007171279A - Method of manufacturing elastic roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a highly precise elastic roller having a small surface defect by measuring an electric resistance of the roller during a molding process and controlling a molding device by the measured value to possess small irregularity and a uniform resistance value in the elastic roller used for an image forming apparatus using an electrophotographic process. <P>SOLUTION: In a pressure rotation heating process for a member of the surface of an elastic member (rubber roller) used for the image forming apparatus using the electrophotographic process, the method of manufacturing the high precise elastic roller comprises applying a voltage during molding, and having the uniform resistance value by controlling the molding device by the electric resistance value of a measured roller. The method predicts the optimum molding condition from the resistance value of the roller after the molding process and has the uniform resistance value by carrying out the molding process in the optimum molding condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing rubber rollers (charging roller, developing roller, etc.) used in an image forming apparatus using an electrophotographic process in office automation equipment such as LBP (Laser Beam Printer), copying machines, and facsimiles.

  Conventionally, many methods of contact charging and contact transfer have been studied in the electrophotographic charging / transfer process. FIG. 1 is a diagram schematically showing the configuration of an electrophotographic apparatus having contact charging means and contact transfer means. Reference numeral 1 denotes an image carrier as a member to be charged, which is a photosensitive member used in a drum type electrophotographic process having a conductive support such as aluminum and at least a photoconductive layer on the outer peripheral surface thereof. Reference numeral 2 denotes a charging member that comes into contact with the photosensitive member and uniformly charges the surface of the photosensitive member to a predetermined potential. This example shows a roller shape (hereinafter referred to as a charging roller).

  This charging roller has at least a central core and an elastic layer (hereinafter referred to as an elastic layer) on the outer peripheral surface thereof. The charging roller is pressed against the photosensitive member 1 with a predetermined pressing force by a pressing means (not shown) such as a spring, and is rotated following the rotation of the photosensitive member 1. Further, the photoconductor 1 is contact-charged to a predetermined potential by applying a DC + AC (or only DC) bias to the core part. That is, in order to obtain a good copy image, the charging member 2 needs to have a uniform contact state with the photoconductor 1 and conductivity. The surface of the photosensitive member 1 charged to a predetermined potential by the charging member 2 is exposed to image information by exposure light 3 output from exposure means (not shown) such as a laser or LED, so that target image information is obtained. An electrostatic latent image corresponding to is formed.

  Next, the latent image is visualized as a toner image by the developing means 4. The toner image is charged from the back of the transfer material 6 with the reverse polarity to the toner by the transfer member 5, whereby the toner image on the surface of the photoreceptor 1 is transferred to the surface side of the transfer material 6. The transfer material 6 that has received the transfer of the toner image is separated from the photoreceptor 1 and fixed by heat and pressure by the fixing member 7. Further, the surface of the photosensitive member 1 after image transfer is cleaned by the cleaning member 8 after removal of deposits such as residual toner at the time of transfer, and is repeatedly used for image formation. In FIG. 1, 9 denotes toner and 10 denotes a rotation axis.

  A roller used for such charging, transfer, developing member, and the like is an elastic roller composed of a cored bar that is rotatably supported at least at both ends, and an elastic layer provided on the outer peripheral surface of the cored bar.

  For example, in the case of a charging roller that is used in contact with a photosensitive member, it is necessary to reduce the resistance of the roller to a medium resistance, and variations in resistance values in the circumferential direction and longitudinal direction of the roller must be suppressed as much as possible. If it is large, unevenness occurs in the image, and it is difficult to obtain a good image.

  Conventionally, such a roller having a resistance in the middle resistance region is obtained by adjusting the resistance value by mixing an electronic conductive powder such as carbon into a polymer and a resin. Large variations are very difficult, and it is difficult to obtain a roller having a uniform resistance value. Accordingly, in order to improve such variation in resistance value, a medium resistance roller is obtained by using an ion conductive polymer composition in which the resistance value is adjusted to a medium resistance region using an ion conductive material as a conductive agent. A method has also been proposed. However, ion-conductive polymers are easily affected by moisture in the atmosphere, and the ion mobility increases in high-temperature and high-humidity environments and low-temperature and low-humidity environments. There is a problem that the environmental stability of the resistance value is inferior to that of the system.

  Such uniformity and stability of the resistance value is one of important performances not only for the charging member such as the charging roller but also for other electrophotographic members such as a transfer member and a developing member. Therefore, development of an elastic roller for electrophotography excellent in uniformity and stability of resistance value is desired.

Also, if there are defects such as large dents and holes on the roller surface, image defects may occur. Therefore, as a technique for reducing the surface defects of the roller, the unvulcanized rubber composition on the metal core is pressed with a pressure contact member. Although a method for smoothing the surface by pressing and heating rotation in which heating is performed while rotating is proposed (for example, see Patent Document 1), there is no description regarding the resistance value of the roller.
JP 2000-177005 A

  The present invention has been made in view of the above problems, and an object of the present invention is to measure an electrical resistance of a roller during a molding process in an elastic roller used in an image forming apparatus using an electrophotographic process, and use the measured value as a molding apparatus. It is an object of the present invention to provide a method for manufacturing a highly accurate elastic roller with less variation in resistance and less surface defects. Another object is to predict the optimum molding conditions from the molding conditions in the molding process and the resistance value of the roller after the molding process or after vulcanization, and to carry out the molding process under the optimum molding conditions, so that the conductive filler is contained. Another object of the present invention is to provide a method of controlling the resistance of a roller by a molding method using a material to be manufactured, that is, a method of manufacturing a roller having different resistance values.

  The above-mentioned problems and objects are solved and achieved by the present invention described below.

  1. A process of coating the unvulcanized rubber composition on the core metal by extruding the unvulcanized rubber composition together with the core metal, and a state in which the surface of the unvulcanized rubber composition on the core metal is pressed by a pressure contact member In a method of manufacturing an elastic roller, wherein the heating is performed while rotating the surface of the unvulcanized rubber composition on the core metal while applying pressure to the pressure contact member. However, it is provided with a means for measuring the electric resistance of the unvulcanized rubber composition by applying a voltage between the metal core and the pressure contact member, and a pressure rotation heating process by the pressure contact member based on the measured electric resistance value It is an object of the present invention to provide a method for manufacturing an elastic roller, wherein feedback control is performed on at least one of a pressurizing time, a pressurizing force, a heating temperature, and a rotational speed of a pressure contact member.

  2. A process of coating the unvulcanized rubber composition on the core metal by extruding the unvulcanized rubber composition together with the core metal, and a state in which the surface of the unvulcanized rubber composition on the core metal is pressed by a pressure contact member In a method of manufacturing an elastic roller, characterized in that the electrical resistance of the elastic roller is measured during molding, after molding, or after vulcanization / every time. The elastic roller having the required electrical resistance value is determined from at least one molding condition consisting of the electrical resistance value and the pressurizing time or pressurizing pressure, heating temperature or rotational speed of the pressurizing member in the pressurizing and rotating process. An elastic roller manufactured by predicting molding conditions, determining the predicted molding conditions as optimum molding conditions, and performing a pressurizing rotation heating process with a pressure contact member under the optimum molding conditions. It is to provide a method.

  3. The unvulcanized rubber composition contains at least a conductive filler and is to provide a method for producing an elastic roller according to the above 1-2.

4). The conductive filler is carbon black, and at least the carbon black contained therein has a nitrogen adsorption specific surface area of A (m ² / g), a DBP oil absorption of B (ml / 100 g), and an added part by weight with respect to 100 parts by weight of rubber. It is to provide the method for producing an elastic roller according to the above 1 or 2, wherein the carbon black satisfies the relationship of the formulas (I) and (II), where C is C.

Formula (I) 1000 ≦ Σ (A × C) ≦ 100,000
Formula (II) 2500 ≦ Σ (B × C) ≦ 50,000

  The present invention relates to a method for producing a rubber roller for use in an image forming apparatus utilizing an electrophotographic process, by extruding a kneaded unvulcanized rubber composition mixed with a polymer raw material and an additive together with a core metal onto the core metal. A step of coating an unvulcanized rubber composition, and a molding step of heating while rotating the surface of the unvulcanized rubber composition on the core metal while being pressed by a pressure contact member. By measuring the electrical resistance by applying a voltage between the member and controlling the molding device in the pressurizing rotation heating process with the pressure contact member based on the measured electrical resistance value, there is no defect on the surface, the surface Since an elastic roller having good roughness, high shape accuracy, and uniform resistance can be obtained stably, not only the manufacturing cost can be reduced, but also the quality as a product can be improved. In addition, since the optimum molding conditions of the roller having the required resistance value can be determined from the electrical resistance value of the elastic roller after molding or vulcanization and the molding condition of the pressure contact member, an unvulcanized rubber composition containing a conductive filler It is possible to reduce the resistance variation caused by the lot, and to obtain a product having a stable resistance.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  First, the manufacturing method of the elastic body roller of this invention is demonstrated.

  Here, FIG. 2 shows a schematic diagram of an extruder used in the present invention. In FIG. 2, the extruder 11 includes a crosshead 12. The cross head 12 can insert the cored bar 14 fed from the cored bar feeding roller 13 from behind, and can simultaneously extrude the cylindrical unvulcanized rubber composition simultaneously with the cored bar 14. After the unvulcanized rubber composition was coated and formed in a cylindrical shape around the core metal, the end portion was cut and removed 15 to obtain an unvulcanized roller 16.

  The material used as the core metal is preferably a stainless steel rod, a phosphor bronze rod, an aluminum rod, a heat-resistant resin rod or the like including a steel material such as a nickel-plated or chrome-plated SUM material, but is not particularly limited thereto. Absent.

  Examples of the polymer raw material used in the present invention include natural rubber, butadiene rubber, styrene butadiene rubber (SBR), nitrile rubber, ethylene propylene rubber (EPDM), chloroprene rubber (CR), nitrile butadiene rubber (NBR), epichlorohydrin rubber, There are rubbers such as butyl rubber, silicone rubber, urethane rubber, fluorine rubber, and chlorine rubber.

  These rubbers can be used alone or blended. Further, a thermoplastic material or a mixture of a thermoplastic material and a rubber material may be used.

  In addition, vulcanized rubber is treated by cutting, grinding, grinding, etc. to add rubber pieces or rubber powder, or rubber powder that has been molded and vulcanized into a sphere of 1 nm to 200 μm. You can also.

  Moreover, a vulcanizing agent, a vulcanization accelerator, a conductive agent, a charge control agent, a plasticizer, an antiaging agent, and the like can be appropriately added to the rubber material. Furthermore, an antistatic agent, an ultraviolet absorber, a reinforcing agent, a filler, a lubricant, a release agent, a pigment, a dye, a flame retardant, and the like can be appropriately added as necessary.

Examples of the conductive filler dispersed in the polymer raw material to obtain the effect of the present invention include carbons such as carbon black and conductive carbon, graphite, gold oxides such as TiO ₂ , SnO ₂ and ZnO, SnO ₂ and the like. Various known materials such as a solid solution of Sb ₂ O ₃ , a double oxide such as a solid solution of ZnO and Al ₂ O ₃ , metal powders such as Cu and Ag can be used. May be used.

More preferably, carbon black is added. At least the nitrogen adsorption specific surface area of the carbon black contained is A (m ² / g), the DBP oil absorption is B (ml / 100 g), and the added weight with respect to 100 parts by weight of the polymer raw material. The effect of the present invention can be further enhanced by adding the carbon black to the raw material polymer in such a range that the carbon black satisfies the relationship of the formulas (I) and (II).

Formula (I) 1000 ≦ Σ (A × C) ≦ 100,000
Formula (II) 2500 ≦ Σ (B × C) ≦ 50,000
The above formula (I) and formula (II) will be described. In general, as one of the indicators of carbon black exhibiting conductivity in a dispersed state in a raw material polymer, it is known that a material having a large value of nitrogen adsorption specific surface area and DBP oil absorption is high in conductivity. For example, in order to obtain a roller having a required resistance value as a charging roller, it is possible to achieve it by adding a small amount of carbon black with high conductivity or a large amount of carbon black with low conductivity. I was asked. As a result of further intensive studies, the sum of the product of the nitrogen adsorption specific surface area and the added part by weight of each carbon black to be added is 1000 or more and 100,000 or less, and the sum of the product of the DBP oil absorption and the added part by weight is 2500 or more and 50000. The effects of the present invention can be effectively obtained in the following cases. For the lower limit, the conductivity is insufficient to obtain the effect of the present invention, that is, the electronic conductivity is not shown, so the upper limit is too high to obtain a desired resistance value. That is, it is set because the resistance is too low.

  Moreover, you may provide electroconductivity, using a conductive polymer, an ionic conductive agent, etc. together with the said conductive filler.

  As the material of the pressure contact member in a heated state to be brought into contact while rotating the surface of the unvulcanized rubber roller obtained by the method as described above, a metal such as stainless steel, iron, aluminum, copper, brass or the like is preferable. It is preferable to use a metal having high properties and high processing accuracy. In addition, the pressure contact member may be surface-treated and coated with fluorine coating, fluorine resin / silicone resin, etc. in addition to plating such as chrome plating and nickel plating for the prevention of unvulcanized rubber. For example, a surface treatment of a metal, a coating with a fluorine / silicone release agent, a DLC (diamond-like carbon) vapor deposition, or other known metals can be used.

  Next, the shape and surface roughness of the pressure contact member will be described.

  If a pressure contact member smaller than the width of the rubber portion of the unvulcanized roller is used as the shape of the pressure contact member, if pressure is concentrated on only a part of the unvulcanized roller, a mark may remain on the appearance. Therefore, it is preferable to apply pressure by the pressure contact member while continuously rotating, and to continuously shift the place where the pressure is applied. Since it moves in the longitudinal direction while being heated and rotated, a spiral heating history is generated, which may affect the resistance unevenness of the roller. Therefore, it is more preferable to use a member longer than the length of the rubber portion of the unvulcanized rubber roller. The contact surface may be planar, but is preferably curved.

  First, the case where the contact surface between the pressure contact member and the unvulcanized rubber roller has a curved shape will be described. Specifically, a cylindrical pressure contact member may be used. In the case of a cylindrical pressure contact member, it is possible to apply pressure while continuously changing the position by bringing the unvulcanized rubber roller into contact with the rotating pressure contact member while applying pressure to both ends of the core bar and rotating the roller. it can. As the cylindrical pressure contact member, a cylindrical member having an inner diameter larger than the outer diameter of the unvulcanized rubber roller may be used and rotated while being in contact with the inner peripheral surface.

  Next, the case where the contact surface between the pressure contact member and the unvulcanized rubber roller has a planar shape will be described. Specifically, a flat plate pressure contact member may be used. In the case of a flat plate-shaped pressure contact member, pressure can be applied while continuously changing the position by pressing both ends of the core metal and rotating the unvulcanized rubber roller while pressing it.

  In order to make the obtained rubber roller into a crown shape or an inverted crown shape having different outer diameters in the longitudinal direction, when the pressure contact member is cylindrical, the crown shape (the outer diameter of the central portion is larger than the outer diameter of the end portion), Or what is necessary is just to heat using the press-contact member of a reverse crown shape (the outer diameter of a center part is smaller than the outer diameter of an edge part). Moreover, you may use the unvulcanized roller which gave the outer diameter difference previously.

  As for the surface roughness of the pressure contact member, it is possible to control the surface roughness of the rubber roller by setting the surface roughness to the same level as the desired surface roughness in order to obtain the desired surface roughness.

  Regarding the heating method of the pressure contact member, any method such as a hot stove, vulcanizer, hot platen, far / near infrared, induction heating, heating wire, etc. may be used in combination, and the temperature is in the range of 120 ° C. or higher and 220 ° C. or lower. It is preferable that it is heated uniformly.

  Regarding the heating method of the unvulcanized rubber roller, any method such as a hot stove, a vulcanizing can, a hot platen, far / near infrared rays, induction heating, etc. may be used together with a heating process using a pressure contact member. It is preferable to heat at a temperature in the following range for 10 minutes to 180 minutes.

  The pressure load on the pressure contact member of the unvulcanized rubber roller can be adjusted as appropriate depending on the viscosity of the rubber material. Depending on the weight of the core metal, only its own weight may be used. It is preferable to apply the above method or to apply a uniform surface pressure to the length of the roller rubber. The load may be applied by any method such as spring pressure or air pressure.

  FIG. 3 is a schematic diagram (A is a front view, B is a side view) of a pressure vulcanizing apparatus having a cylindrical pressure contact member used in the present invention.

  The center of the rotating cylindrical pressure contact member 17 and the unvulcanized rubber roller 16 extruded integrally with the core metal are held in parallel, and the holding member 18 for pressing the both ends of the unvulcanized rubber roller is pushed. It is held so that the shaft does not shift from side to side. The pressure contact member is provided with a heating infrared heater 19 (halogen lamp heater) at the center, and is preheated to a heating temperature. By rotating the pressure contact member by the motor 20, the unvulcanized rubber roller can be driven to rotate. Further, the applied pressure can be adjusted by changing the load 21. Further, a DC power source 22 is arranged so that a voltage is applied to the unvulcanized rubber roller, and a multimeter 23 is arranged so as to measure the roller resistance value. It is possible to simultaneously apply and measure the voltage and voltage.

  When the pressure contact member and the unvulcanized rubber roller come into contact with each other, the unvulcanized rubber roller is energized from the pressure contact member. The resistance value of the unvulcanized rubber roller can be obtained by measuring the current using, for example, a multimeter or an ammeter. For example, when the resistance value of the rubber roller does not reach the specified value when the detected resistance value is monitored and the resistance value of the rubber roller does not reach the specified value when the preset heating contact time is reached, the heating rotation process time is set to the specified value. When the resistance value of the rubber roller reaches the specified value before the set time, the pressure contact member and the rubber roller are separated from each other and the heating rotation process is ended, or the heating temperature of the pressure contact member is increased or decreased. Perform feedback control such as changing the heating temperature of the pressure contact member so that the resistance value of the elastic roller reaches the specified value in the set time, changing the pressure applied by the pressure contact member, or changing the rotation speed of the pressure contact member. Thus, it becomes possible to manufacture an elastic roller having a uniform resistance value. Regarding the application of the voltage, it may be applied throughout the heating rotation process, or may be applied at a set time interval (for example, every 15 seconds). The molding conditions for the pressure contact member that performs feedback control include, for example, the pressure contact time, pressure, temperature, and rotational speed of the pressure contact member. These molding conditions may be controlled individually or in combination. good.

  In addition to the method of controlling the resistance value of the roller, in addition to the method of performing feedback control for each roller based on the resistance value measured by applying a voltage between the pressure contact member and the unvulcanized rubber roller as described above, A pressure contact member for measuring a resistance value of a roller after pressure rotary heating molding or secondary vulcanization by a pressure contact member, and manufacturing a roller having a required resistance value from the relationship between the measured resistance value and molding conditions. There is a method of predicting the optimum molding conditions by the method and performing the pressure rotary heating molding process under the predicted optimum molding conditions.

  The method for estimating the optimum molding condition will be described below by taking the pressure contact time by the pressure contact member as an example, but the same method can also be used in the case of other molding conditions such as pressure contact force, temperature, and rotation speed.

  In the pressure rotary thermoforming process with the pressure contact member, an elastic roller is prepared by changing the pressure contact time with the pressure contact member at least at least 2 points, preferably about 5 points in advance, and the roller resistance value is measured. When the measured roller resistance value is plotted with respect to the pressure contact time, it can be seen that when the pressure contact time is extended, the resistance value of the rubber roller increases according to the pressure contact time. In other words, it is clear that there is a correlation between the roller resistance value and the molding condition by the pressure contact member, and the optimum pressure contact time by the pressure contact member for manufacturing the rubber roller having the required resistance value is estimated from the relationship between the roller resistance value and the molding condition. The greatest feature of the present invention is that it is possible to obtain rollers having different resistance values by changing molding conditions even with the same material.

  As described above, the relationship between the molding condition by the pressure contact member and the resistance value of the rubber roller increases the resistance when the pressure is increased, increases the resistance when the applied pressure is increased, and increases the resistance when the heating temperature is increased. The rate of change may vary depending on the blending amount and type of the conductive filler, the polymer type, other additives, and the like.

  By using this method, even when the resistance value of the unvulcanized rubber composition varies to some extent due to, for example, the difference in the kneading lot of the unvulcanized rubber composition, the optimum molding conditions are estimated in advance and estimated. By performing the heating and rotating step with the pressure contact member under the optimum molding conditions, it is possible to manufacture a roller that suppresses variation in resistance value of the unvulcanized rubber composition lot.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to these.

<Preparation of unvulcanized rubber composition>
Epichlorohydrin rubber (trade name “Epichromer (Epichromer is a registered trademark) CG105”: manufactured by Daiso Co., Ltd.) 100 parts by mass, 5 parts by mass of zinc oxide (Zinc Oxide Two Kinds of Chemicals), 1 part by mass of stearic acid As a conductive filler, 35 parts by mass of carbon black (manufactured by Asahi Carbon Co., Ltd., HS500) was kneaded with an open roll for 30 minutes. Furthermore, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 1 part by mass of a vulcanization accelerator (TS: tetramethylthiuram monosulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent And kneaded with an open roll for 15 minutes to prepare an unvulcanized rubber composition.

  Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2).

  Next, a stainless bar core bar having an outer diameter of 6 mm and a length of 258 mm was prepared. Here, a cylindrical unvulcanized rubber composition was molded around the core metal by integrally extruding the core metal and rubber using an extruder schematically shown in FIG. Thereafter, the end portion was cut and removed so that the length of the unvulcanized rubber composition was 232 mm to obtain an unvulcanized rubber roller (unvulcanized rubber roller outer diameter φ8.5 mm). Thereafter, unless otherwise specified, unvulcanized rubber rollers were prepared by this method.

  Using the pressure heating apparatus schematically shown in FIG. 3, the unvulcanized rubber roller is subjected to pressure rotary thermoforming using a cylindrical pressure contact member heated to 145 ° C., and a load of 1 kg is applied to both ends of the unvulcanized rubber roller. I went. At the same time as the press-rotating and heat-forming by the pressure contact member, a DC voltage of 200V is applied between the cylindrical pressure contact member and the unvulcanized rubber roller, and when the measured roller resistance value reaches 2 * 10 ^ 6Ω, the pressure contact member Was separated to obtain a rubber roller. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller. FIG. 4 shows the roller resistance value when each of these rubber rollers is pulled out and a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%). It was found that rubber rollers with almost constant resistance were obtained stably. This rubber roller is incorporated in an electrophotographic cartridge as a charging roller in a low-temperature and low-humidity environment (15 ° C., 10%), and is pressed into contact with both ends of the photosensitive drum with a load of 500 g. This rubber roller (charging roller) Was used to evaluate the image by halftone. In this evaluation, the rubber roller (charging roller) of the present example was able to obtain a good image without charging failure due to resistance unevenness and image failure due to surface defects such as dents. Thereafter, unless otherwise specified, image evaluation of the rubber roller was performed by this method.

<Preparation of unvulcanized rubber composition>
Epichlorohydrin rubber (trade name "Epichromer (Epichromer is a registered trademark) CG105": manufactured by Daiso Co., Ltd.) 100 parts by mass, 5 parts by mass of zinc oxide (Zinc Oxide Type 2) and 1 part by mass of stearic acid As a conductive filler, 2 parts by mass of Ketchen Black (trade name “EC600JD” manufactured by Lion Corporation) and 15 parts by mass of carbon black (HS500 manufactured by Asahi Carbon Co., Ltd.) were kneaded with an open roll for 30 minutes. Furthermore, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 1 part by mass of a vulcanization accelerator (TS: tetramethylthiuram monosulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent And kneaded with an open roll for 15 minutes to prepare an unvulcanized rubber composition. Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2). An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that this unvulcanized rubber composition was used. This unvulcanized rubber roller is subjected to pressure rotary thermoforming by a cylindrical pressure member heated to 145 ° C. using a pressure heating apparatus schematically shown in FIG. 3, and a load of 1 kg is applied to both ends of the unvulcanized rubber roller. Then, the welding was performed at six levels of pressure contact time of 30, 60, 90, 120, 150, and 180 seconds. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller.

  FIG. 5A is a graph in which the roller resistance value of this rubber roller when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the pressure contact time. From FIG. 5A, it was confirmed that the resistance of the rubber roller increased as the pressure contact time increased. From the approximate curve shown in FIG. 5A, a pressing time of 120 seconds was set as the optimum molding condition. A rubber roller was obtained in the same manner as described above except that the pressure contact time was fixed at 120 seconds and pressurization was performed. FIG. 5B is a graph plotting the roller resistance values when each of the rubber rollers is pulled out every 10 and a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%). From FIG. 5B, it was confirmed that it was possible to produce a roller with little resistance variation between the rollers.

<Preparation of unvulcanized rubber composition>
Epichlorohydrin rubber (trade name "Epichromer (Epichromer is a registered trademark) CG105": manufactured by Daiso Co., Ltd.) 100 parts by mass, 5 parts by mass of zinc oxide (Zinc Oxide Type 2) and 1 part by mass of stearic acid In addition, 60 parts by mass of SRF-carbon (trade name: Asahi # 35 manufactured by Asahi Carbon Co., Ltd.) as a conductive filler was kneaded with an open roll for 30 minutes. Furthermore, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 1 part by mass of a vulcanization accelerator (TS: tetramethylthiuram monosulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent And kneaded with an open roll for 15 minutes to prepare an unvulcanized rubber composition. Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2).

  An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that this unvulcanized rubber composition was used. Using this unvulcanized rubber roller, pressure rotation heating molding was carried out in the same 6-level pressure contact time as in Example 2 to obtain a rubber roller. FIG. 6 shows a graph in which the roller resistance value of this rubber roller when the DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the pressure contact time. From FIG. 6, it was confirmed that the resistance of the rubber roller increased as the pressure contact time increased.

<Preparation of unvulcanized rubber composition>
For 100 parts by mass of NBR (trade name “N230S” manufactured by JSR), 5 parts by mass of zinc oxide (Zinc Oxide Two Kinds of Chemicals), 1 part by weight of stearic acid, and Ketchen Black (trade name “Product Name“ EC600JD “Lion Co., Ltd.) 6 parts by mass, carbon black (HS500 Asahi Carbon Co., Ltd.) 14 parts by mass, calcium carbonate (trade name“ Nanox # 30 ”Maruo Calcium Co., Ltd.) 30 parts by mass as an open roll 30 Kneaded for a minute. Further, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent were added and kneaded with an open roll for 15 minutes to form an unvulcanized rubber composition. A product was made. Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2).

  An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that this unvulcanized rubber composition was used. The unvulcanized rubber roller is pressed at 125, 145, and 155 ° C. using a pressure heating apparatus schematically shown in FIG. 3, applying a load of 1 kg to both ends of the unvulcanized rubber roller and fixing the pressure contact time to 120 seconds. Pressurized rotary thermoforming was performed with a cylindrical pressure contact member preheated to three levels. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller.

  FIG. 7 shows a graph in which the roller resistance value of this rubber roller when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the heating temperature of the press contact member. From FIG. 7, it was confirmed that the resistance of the rubber roller increased as the heating temperature of the pressure contact member increased.

  An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that the unvulcanized rubber composition used in Example 4 was used. Using the pressure heating apparatus schematically shown in FIG. 3, this unvulcanized rubber roller is fixed in a pressure contact time of 120 seconds, and is subjected to pressure rotary thermoforming using a cylindrical pressure contact member heated to 145 ° C. The test was carried out by applying four levels of loads of 1, 2, 3, 4 kg to both ends. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller.

  FIG. 8 is a graph in which the roller resistance value of this rubber roller when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the pressure applied by the loads at both ends. From FIG. 8, it was confirmed that the resistance of the rubber roller increased as the pressure applied to the roller increased.

(Comparative Example 1)
<Preparation of unvulcanized rubber composition>
Epichlorohydrin rubber (trade name “Epichromer (Epichromer is a registered trademark) CG105”: manufactured by Daiso Co., Ltd.) 100 parts by mass, 5 parts by mass of zinc oxide (Zinc Oxide Type 2 Chemicals), 1 part by mass of stearic acid Carbon black (trade name: Seast SO Tokai Carbon) as the conductive filler, 1 part by mass of tetrabutylammonium perchlorate as the ionic conductive agent, calcium carbonate as the filler (trade name “Nanox # 30” Maruo Calcium Co., Ltd. )) 30 parts by mass were kneaded with an open roll for 30 minutes. Furthermore, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 1 part by mass of a vulcanization accelerator (TS: tetramethylthiuram monosulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent And kneaded with an open roll for 15 minutes to prepare an unvulcanized rubber composition. Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2).

  An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that this unvulcanized rubber composition was used. Using this unvulcanized rubber roller, a pressure roller was formed by pressing and pressing with a pressure contact member in the same manner as in Example 2 except that the pressure contact time was three levels of 60, 180, and 300 seconds to obtain a rubber roller. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller. FIG. 9 shows a graph in which the roller resistance value of this rubber roller is plotted with respect to the pressure contact time when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%). From FIG. 9, it was confirmed that when the unvulcanized rubber composition of Comparative Example 1 was used, the resistance of the rubber roller was not substantially changed even when the pressure contact time was increased.

(Comparative Example 2)
An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that the unvulcanized rubber composition used in Comparative Example 1 was used. Except for heating the pressure contact member to three levels of 140, 155, and 170 ° C. using this unvulcanized rubber roller, pressure rotation heating molding was performed with the pressure contact member in the same manner as in Example 4 to obtain a rubber roller. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller. FIG. 10 shows a graph in which the roller resistance value of this rubber roller when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the heating temperature of the pressure contact member. From FIG. 10, it was confirmed that when the unvulcanized rubber composition of Comparative Example 1 was used, the resistance of the rubber roller was not substantially changed even when the heating temperature of the pressure contact member was increased.

(Comparative Example 3)
An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that the unvulcanized rubber composition used in Comparative Example 1 was used. Using this unvulcanized rubber roller, pressurizing, rotating and heat-molding with a pressure contact member in the same manner as in Example 5 above except that three levels of load of 1, 2, 3 kg are applied to both ends of the unvulcanized rubber roller. Obtained. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller. FIG. 11 is a graph in which the roller resistance value of this rubber roller when a DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the pressure applied by the loads at both ends. From FIG. 11, it was confirmed that when the unvulcanized rubber composition of Comparative Example 1 was used, the resistance of the rubber roller was not substantially changed even when the pressure applied to the roller was increased.

(Comparative Example 4)
<Preparation of unvulcanized rubber composition>
Epichlorohydrin rubber (trade name "Epichromer (Epichromer is a registered trademark) CG105": manufactured by Daiso Co., Ltd.) 100 parts by mass, 5 parts by mass of zinc oxide (Zinc Oxide Type 2) and 1 part by mass of stearic acid Then, 35 parts by mass of MT-carbon (N990) as a conductive filler was kneaded with an open roll for 30 minutes. Furthermore, 1 part by mass of a vulcanization accelerator (DM: di-2-benzothiazolyl disulfide), 1 part by mass of a vulcanization accelerator (TS: tetramethylthiuram monosulfide) and 1.2 parts by mass of sulfur as a vulcanizing agent And kneaded with an open roll for 15 minutes to prepare an unvulcanized rubber composition. Table 1 shows the blending amount of the conductive filler and the calculation results of the formulas (1) and (2).

  An unvulcanized rubber roller was obtained in the same manner as in Example 1 except that this unvulcanized rubber composition was used. Using this unvulcanized rubber roller, a pressure roller heating molding was performed by a pressure contact member in the same manner as in Example 2 except that the pressure contact time was three levels of 60, 120 and 180 seconds to obtain a rubber roller. Thereafter, heat vulcanization was performed at 160 ° C. for 120 minutes to obtain a rubber roller. FIG. 12 shows a graph in which the roller resistance value of this rubber roller when the DC voltage of 200 V is applied in a low temperature and low humidity environment (15 ° C., 10%) is plotted with respect to the pressure contact time. From FIG. 12, it was confirmed that when the unvulcanized rubber composition of Comparative Example 4 was used, the resistance of the rubber roller was not substantially changed even when the pressure contact time was increased.

Schematic configuration diagram of an image forming apparatus Schematic diagram of extruder Schematic diagram of a pressure heating device for a cylindrical pressure welding member (A is a front view, B is a side view) Extraction roller resistance value in Example 1 Relationship between pressure contact time and roller resistance value and extraction roller resistance value in Example 2 Relationship between pressure contact time and roller resistance value in Example 3 Relationship between pressure member heating temperature and roller resistance value in Example 4 Relationship between pressure force and roller resistance value in Example 5 Relationship between pressure contact time and roller resistance value in Comparative Example 1 Relation between pressure member heating temperature and roller resistance value in Comparative Example 2 Relationship between pressure force and roller resistance value in Comparative Example 3 Relationship between pressure contact time and roller resistance value in Comparative Example 4

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging member 3 Exposure light 4 Developing member 5 Transfer member 6 Transfer material 7 Fixing member 8 Cleaning member 9 Toner 10 Rotating shaft 11 Extruder 12 Crosshead 13 Core metal feed roller 14 Core metal 15 Cutting / removal processing 16 Not yet Vulcanizing roller 17 Pressure contact member 18 Holding member 19 Infrared heater for heating 20 Motor 21 Load 22 DC power supply 23 Multimeter

Claims (4)

  A process of coating the unvulcanized rubber composition on the core metal by extruding the unvulcanized rubber composition together with the core metal, and a state in which the surface of the unvulcanized rubber composition on the core metal is pressed by a pressure contact member In a method of manufacturing an elastic roller, wherein the heating is performed while rotating the surface of the unvulcanized rubber composition on the core metal while applying pressure to the pressure contact member. However, it is provided with a means for measuring the electric resistance of the unvulcanized rubber composition by applying a voltage between the metal core and the pressure contact member, and a pressure rotation heating process by the pressure contact member based on the measured electric resistance value A method of manufacturing an elastic roller, wherein feedback control is performed on at least one of a pressurizing time, a pressurizing force, a heating temperature, and a rotational speed of the press contact member in step.   A process of coating the unvulcanized rubber composition on the core metal by extruding the unvulcanized rubber composition together with the core metal, and a state in which the surface of the unvulcanized rubber composition on the core metal is pressed by a pressure contact member In a method of manufacturing an elastic roller, characterized in that the electrical resistance of the elastic roller is measured during molding, after molding, or after vulcanization / every time. The elastic roller having the required electrical resistance value is determined from at least one molding condition consisting of the electrical resistance value and the pressurizing time or pressurizing pressure, heating temperature or rotational speed of the pressurizing member in the pressurizing and rotating process. An elastic roller manufactured by predicting molding conditions, determining the predicted molding conditions as optimum molding conditions, and performing a pressurizing rotation heating process with a pressure contact member under the optimum molding conditions. Method.   The method for producing an elastic roller according to claim 1, wherein the unvulcanized rubber composition contains at least a conductive filler. The conductive filler is carbon black, and at least the carbon black contained therein has a nitrogen adsorption specific surface area of A (m ² / g), a DBP oil absorption of B (ml / 100 g), and an added part by weight with respect to 100 parts by weight of rubber. The method for producing an elastic roller according to claim 1, wherein the carbon black satisfies the relationship of the formulas (I) and (II), where C is C.
Formula (I) 1000 ≦ Σ (A × C) ≦ 100,000
Formula (II) 2500 ≦ Σ (B × C) ≦ 50,000

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