JP2010058278A - Extruder and method for manufacturing rubber roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extruder in which the outside diameter of an individual integrated molding can be restrained from being varied among the extruded integrated moldings. <P>SOLUTION: The extruder 1 is provided with: a cross-head die 2; a cylinder 3 communicated with the cross-head die 2; a screw 4 which is housed in the cylinder 3 and rotated to supply a rubber material 11 to the cross-head die 2; a drive part 10 for rotating the screw 4; a control part 9 for driving the drive part 10; a core bar supply part 6 for supplying a core bar 12 to the cross-head die 2; a measurement part 9a for measuring the outside diameter of the integrated molding 13 extruded from the cross-head die 2; and a computer 9b for computing such a rotational speed of the screw 4 that the measured value becomes a predetermined target value. The control part 9 drives the drive part 10 so that the rotational speed of the screw 4 becomes the rotational speed computed by the computer 9b and then the integrated molding 13 of the rubber material 11 with the core bar 12 is extruded from the cross-head die 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an extruder and a method for manufacturing a rubber roller.

  The rubber roller manufacturing method generally includes an extrusion process in which a rubber material and a metal core are integrated by an extruder equipped with a crosshead die.

  FIG. 3 is a schematic view showing the configuration of an extruder related to the present invention.

  The extruder 101 has a crosshead die 102 for extrusion molding, a cylinder 103 communicating with the internal space of the crosshead die 102, and a screw 104 accommodated in the cylinder 103. The crosshead die 102 includes a die 102a in which an opening for communicating the internal space and the external space of the crosshead die 102 is formed.

  The extruder 101 is configured such that when the screw 104 is rotated, the rubber material 111 loaded in the cylinder 103 is supplied to the internal space of the crosshead die 102.

  Further, the extruder 101 has a core metal supply unit 106. The metal core supply unit 106 includes a metal core guide 107 that guides the metal core 112 to the internal space of the crosshead die 102, a metal core conveyance unit 108 that continuously conveys the plurality of metal cores 112 to the metal core guide 107, have.

  The cored bar transport unit 108 transports the cored bar 112 to the cored bar guide 107 at a constant speed by sandwiching the cored bar 112 between the rollers and rotating the roller. The core metal 112 conveyed to the core metal guide 107 is guided by the core metal guide 107 and supplied to the internal space of the crosshead die 102.

  In the extruder 101, the rubber material 111 is supplied from the cylinder 103 to the internal space of the crosshead die 102, and at the same time, the core metal 112 is supplied to the internal space of the crosshead die 102.

  In the internal space of the cross head die 102, there is a close contact portion 102b where the rubber material 111 and the cored bar 112 are in contact with each other at a position close to the opening of the die 102a. The rubber material 111 and the core metal 112 are brought into close contact with each other at the contact portion 102b, and the integrally formed body 113 of the rubber material 111 and the core metal 112 is pushed out from the opening of the die 102a.

  As described above, in the extruder 101, the integrally formed body 113 of the rubber material 111 and the cored bar 112 is formed.

  The rubber roller manufacturing process generally includes a vulcanization process for vulcanizing the rubber material 111 of the integrally formed body 113 covering the cored bar 112, which is performed after the extrusion process. In the vulcanization step, the integrally formed body 113 is conveyed into a hot stove by a conveyor, and the rubber material 111 is vulcanized. Thereafter, the integrally molded body 113 in which the rubber material 111 is vulcanized is cut into a predetermined length.

  In addition, after the vulcanization process, a grinding process is performed in which the rubber material 111 of the integrally formed body 113 is ground to process the integrally formed body 113 into a predetermined shape. In the grinding step, the rubber material 111 is ground by pressing a grindstone against the rubber material 111 of the integrally formed body 113 rotated around the core metal 112. Thereby, the rubber material 111 of the integrally molded body 113 is processed into a predetermined shape, and the rubber roller is completed.

  In the grinding step, in order to uniformly grind the rubber material 111 of the integrally molded body 113 in the longitudinal direction, it is desirable to press the grindstone against the rubber material 111 with a uniform force over the longitudinal direction of the integrally molded body 113. For that purpose, it is necessary to use a grindstone having a width wider than the length in the longitudinal direction of the rubber material 111 of the integrally molded body 113.

  In the grinding process, the rubber material 111 of the integrally formed body 113 can be processed into various shapes with high accuracy by changing the shape of the grindstone. Thereby, rubber rollers of various shapes can be produced.

  As the shape of the rubber roller, a straight shape having the same outer diameter in the longitudinal direction, a crown shape having a larger outer diameter in the central portion than both end portions in the longitudinal direction, and the like are conceivable. A shape having a plurality of tapered shapes in the longitudinal direction is also conceivable.

  However, since the outer diameter of the individual integrally formed body 113 formed in the extrusion process may vary, it is necessary to grind the rubber material 111 in accordance with the shape of the individual integrally formed body 113 in the grinding process. is there. Therefore, there is a problem that the grinding process takes time. In addition, there are problems that it takes time to replace the grindstone and process the grinding powder, and that the rubber material 111 to be ground is wasted.

  An example of an extruder having the above-described configuration is described in Patent Document 1.

  Patent Document 2 describes a rubber roller manufacturing method in which such a problem is solved.

  In the extruder used in the extrusion process of this rubber roller manufacturing method, the supply speed of the rubber material from the cylinder to the crosshead die is controlled by controlling the screw rotation speed to be a constant condition. Further, the supply speed of the metal core to the crosshead die is adjusted in accordance with the supply speed of the rubber material.

  Since the outer diameter of the integrally formed body mainly depends on the supply speed of the rubber material to the crosshead die, this extruder can suppress variations in the outer diameter among the individual integrally formed bodies.

Thus, it is not necessary to grind the rubber material in accordance with the outer diameter of each integrally molded body in the grinding step, and it is only necessary to grind the rubber material under certain conditions for all the integrally molded bodies.
JP 2002-248668 A JP 2004-145012 A

  However, even when an integrally molded body is formed by controlling the screw rotation speed of the extruder and the supply speed of the core bar to be constant, the variation in the outer diameter among the individual molded bodies is also different. It is difficult to keep it below 50 μm.

  This is slightly less than the conditions for the supply speed of rubber material to the crosshead die, but the conditions such as rubber material characteristics, extruder tolerances, screw shape, extruder operating time, etc. are also individually integrated. This is to affect the outer diameter of the molded body. It is difficult to control these conditions simultaneously.

  Accordingly, an object of the present invention is to provide an extruder that can suppress variation in outer diameter between individual integrally molded bodies and a method for manufacturing a rubber roller that can suppress variation in outer diameter of an integrally molded body in an extrusion process. To do.

  In order to achieve the above object, an extruder according to the present invention includes a crosshead die, a cylinder communicating with the crosshead die, and being accommodated in the cylinder and rotated to rotate the cylinder from the cylinder to the crosshead die. A screw for supplying a rubber material; a driving means for rotating the screw; a control means for driving the driving means; and a core metal supplying means for supplying a core metal to the crosshead die. And an extruding machine for extruding an integrally molded body of the core metal from the crosshead die, measuring means for outputting a measured value of an outer diameter of the integrally molded body extruded from the crosshead die, and the measured value Calculating means for calculating the rotational speed of the screw having a predetermined target value, and the rotational speed of the screw is the rotational speed calculated by the calculating means. The control means drives the drive means so as to.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the rubber roller which can suppress the dispersion | variation in the outer diameter of an integrally molded object in the extrusion machine which can suppress the dispersion | variation in the outer diameter between each integral molded object and an extrusion process can be provided.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic view showing a configuration of an extruder according to a first embodiment of the present invention used in an extrusion process during a rubber roller manufacturing process.

  The extruder 1 is a uniaxial vent type extruder, and includes an extrusion molding crosshead die 2, a cylinder 3 communicating with the internal space of the crosshead die 2, and a screw 4 accommodated in the cylinder 3. Have. The crosshead die 2 includes a die 2a in which an opening for communicating the internal space and the external space of the crosshead die 2 is formed.

  The extruder 1 is configured such that when the screw 4 is rotated, the rubber material 11 loaded in the cylinder 3 is supplied to the internal space of the crosshead die 2.

  Further, the extruder 1 has a mandrel supply unit 6. The metal core supply unit 6 includes a metal core guide 7 that guides the metal core 12 to the internal space of the crosshead die 2, a metal core conveyance unit 8 that continuously conveys the plurality of metal cores 12 to the metal core guide 7, have. The core metal transport unit 8 may be an apparatus independent of the extruder 1.

  The cored bar transport unit 8 transports the cored bar 12 to the cored bar guide 7 at a constant speed by sandwiching the cored bar 12 between the rollers and rotating the roller. The core metal 12 conveyed to the core metal guide 7 is guided by the core metal guide 7 and supplied to the internal space of the crosshead die 2.

  In the extruder 1, the rubber material 11 is supplied from the cylinder 3 to the internal space of the crosshead die 2, and at the same time, the core metal 12 is supplied to the internal space of the crosshead die 2.

  In the internal space of the cross head die 2, there is a close contact portion 2b where the rubber material 11 and the cored bar 12 are in contact with each other in the vicinity of the opening of the die 2a. The rubber material 11 and the core metal 12 are brought into close contact with each other at the contact portion 2b, and the integrally molded body 13 of the rubber material 11 and the core metal 12 is pushed out from the opening of the die 2a of the crosshead die 2.

  When the same crosshead die 2 is used, the outer diameter of the integrally molded body 13 extruded from the crosshead die 2 is mainly determined by the supply speed of the rubber material 11 to the crosshead die 2. When the supply speed of the rubber material 11 to the crosshead die 2 is increased, the outer diameter of the integral molded body 13 increases. Conversely, when the supply speed of the rubber material 11 to the crosshead die 2 is decreased, the outer diameter of the integral molded body 13 is increased. Becomes smaller.

  Further, the supply speed of the rubber material 11 to the crosshead die 2 is mainly determined by the rotational speed of the screw 4.

  Further, the extruder 1 has a control unit 9 that controls the rotational speed of the screw 4 by driving the drive unit 10. The control unit 9 measures the outer diameter of the integrally molded body 13 at a position close to the opening of the die 2a of the crosshead die 2 and outputs a measurement value, and is driven according to the measurement value of the measurement unit 9a. And a computer 9b for driving the unit 10.

  For example, a laser length measuring device can be used as the measurement unit 9a. It is desirable that the measurement unit 9a measures 5 to 10 points of the outer diameter of the integrally formed body 13 at regular intervals in the longitudinal direction for one integrally formed body 13.

  However, when the rotational speed of the screw 4 is controlled, variations in the outer diameter of the integrally molded body 13 are unlikely to occur in the single integrally molded body 13 within a relatively narrow range. Therefore, in the extruder 1 which concerns on this embodiment, the number of measurement points by the measurement part 9a about one integral molded object 13 is 1-3 points. Thereby, the measurement by the measurement part 9a can be sped up.

  The target value of the outer diameter of the integrally formed body 13 is set in the computer 9b. Further, the computer 9b has a calculation program for calculating the rotational speed of the screw 4 so that the measurement value of the measurement unit 9a becomes the target value of the outer diameter of the integrally molded body 13. The computer 9b drives the drive unit 10 so that the rotation speed of the screw 4 becomes the rotation speed calculated by the calculation program.

  Thus, the control unit 9 of the extruder 1 controls the rotational speed of the screw 4 so that the outer diameter of the integrally formed body 13 extruded from the crosshead die 2 becomes a set target value. Thereby, in the extruder 1, the dispersion | variation in the outer diameter of the integrally molded body 13 which generate | occur | produces according to conditions, such as the characteristic of a rubber material, the tolerance of an extruder, the shape of a screw, and the operating time of an extruder, can be suppressed. Therefore, in the extruder 1, the outer diameter of the integrally formed body 13 can be kept constant.

  The extruder 1 preferably includes a rotational speed meter (not shown) that outputs a measured value of the rotational speed of the screw 4 and controls the rotational speed of the screw 4 using the measured value of the rotational speed meter. Thereby, the rotational speed of the screw 4 can be controlled more accurately.

  The control unit 9 may include a pressure measurement unit (not shown) that measures and outputs the pressure applied to the rubber material 11 in the crosshead die 2. Thereby, since the computer 9b can also control the rotational speed of the screw 4 also using the measured value of a pressure measurement part, it can control the outer diameter of the integrally molded body 13 more precisely.

  The drive unit 10 uses an electric motor that can easily control the rotation speed. As the electric motor, an inverter-controlled AC motor can be used, but a feedback-controlled servo motor is preferably used. By using the servo motor, the rotational speed of the screw 4 can be controlled more accurately.

  The extruder 1 preferably has a temperature control unit (not shown) that controls the temperature of the crosshead die 2. By controlling the temperature of the crosshead die 2 by the temperature control unit, the characteristics such as the viscosity of the rubber material 11 in the crosshead die 2 can be kept constant. Thereby, the dispersion | variation in the outer diameter of the integrally molded body 13 can be suppressed.

  As a configuration of the temperature control unit, a configuration using temperature-controlled water, a configuration using an electric heater, or the like can be considered. The temperature control unit may be an apparatus independent of the extruder 1. Further, it is desirable that the temperature control unit is further configured to control the temperature of the cylinder 3 and the screw 4.

  As a comparative example of the extruder 1 according to this embodiment, an extruder having a configuration other than the control unit similar to that of the extruder 1 was used, and the screw rotational speed was fixed at 15 rpm, and 3000 integrally formed bodies were produced. When these integrally molded bodies were evaluated, the standard deviation of the outer diameter of the integrally molded body was 0.035 mm.

On the other hand, when the extruder 1 according to this embodiment is used and the initial rotational speed of the screw 4 is 15 rpm and 3000 integrally formed bodies 13 are produced and evaluated, the standard deviation of the outer diameter of the integrally formed body 13 is 0. 009 mm. Thereby, in the extruder 1 which concerns on this embodiment, it was confirmed that the effect which suppresses the dispersion | variation in the outer diameter of each integrated molded body 13 is acquired.
(Second Embodiment)
The method for manufacturing a rubber roller according to the second embodiment of the present invention includes an extrusion process using the extruder according to the first embodiment of the present invention, a general vulcanization process, and a grinding process. Yes.

  The rubber roller manufacturing method according to the present embodiment can be applied to a conductive roller used for a charging roller, a developing roller, a pressure roller, a transfer roller, or the like of an electrophotographic apparatus such as a copying machine or a printer.

  In the extrusion step of the rubber roller manufacturing method according to the present embodiment, the integrally formed body 13 is produced using the extruder 1 according to the first embodiment.

  Moreover, although the thing of various magnitude | sizes can be used for the cylinder 3 and the screw 4 of the extruder 1, in this embodiment, it has the internal diameter corresponding to this screw 4 and the screw 4 whose outer diameter is about 60 mm. Cylinder 3 was used.

  Further, the inner diameter of the opening of the die 2 a of the crosshead die 2 is determined according to the target value of the outer diameter of the integrally molded body 13. In the present embodiment, the die 2a in which the target value of the outer diameter of the integrally molded body 13 is 9.5 mm and the inner diameter of the opening is 9 mm is used.

  Further, as the rubber material 11, materials such as hydrin rubber, nitrile rubber, and EPDM that can be extruded can be used. If necessary, additives such as a conductive filler, a filler, and a plasticizer can be added to these materials. May be added. In this embodiment, the rubber material 11 is a rubber compound in which various fillers, plasticizers, reinforcing materials, and vulcanizing agents are mixed with EPDM.

  Moreover, the shape of the metal core 12 should just be a rod shape, and it is desirable that the cross section orthogonal to a longitudinal direction is circular. The material forming the cored bar 12 may be any material having conductivity, and it is desirable to use an iron alloy or an aluminum alloy. In the present embodiment, the cored bar 12 is a bar having a length of 260 mm and a cross-section perpendicular to the longitudinal direction having a diameter of 6 mm and subjected to chemical plating with a thickness of about 5 μm. The one having a tolerance of 40 μm or less and a deflection of the central portion with respect to both ends was about 50 μm.

  Further, in the core metal transport unit 8 of the extruder 1, the transport speed for transporting the core metal 12 to the core bar guide 7 can be set to various values. In this embodiment, the transport speed of the core metal transport unit 8 is set. Was set to 2 m / min.

  In addition, an adhesive can be applied to the core metal 12 in order to improve the adhesion between the rubber material 11 and the core metal 12 integrated in the close contact portion 2b. As the adhesive, for example, a hot melt type conductive primer or a vulcanized adhesive can be used. In this embodiment, a hot melt type conductive primer mainly composed of a styrene-based resin is applied to a portion other than the portion disposed 14 mm from both ends of the core metal 12 with a thickness of about 10 μm.

  Further, in this embodiment, the extrusion process is performed by controlling the temperature by the temperature control unit of the extruder 1 so that the cylinder 3 and the screw 4 are about 80 ° C. and the crosshead die 2 is about 40 ° C. The initial rotational speed of the screw 4 was 15 rpm.

  Further, the extruder 1 is provided with a take-off cutter (not shown), and the integrated molded body 13 extruded by the extruder 1 is cut into individual core bars 12 by the take-off cutter.

  After the extrusion process, a vulcanization process for vulcanizing the rubber material 11 of the integrally molded body 13 covering the core metal 12 is performed. In the vulcanization step of the rubber roller manufacturing method according to the present embodiment, the integrally molded body 13 is conveyed into a hot air furnace by a conveyor, and the rubber material 11 is vulcanized. Thereafter, the integral molded body 13 is cut into a predetermined length, and the rubber material 11 at both ends of each individual molded body 13 after the cutting is removed, whereby the support portions arranged at both ends of the core metal 12 are removed. Expose.

  After the vulcanization process, a grinding process is performed in which the rubber material 11 of the integrally molded body 13 is ground to process the integrally molded body 13 into a predetermined shape. In the grinding step of the rubber roller manufacturing method according to the present embodiment, the rubber material 11 is ground by pressing a grindstone against the rubber material 11 of the integrally formed body 13 rotated about the core metal 12. Thereby, the rubber material 11 of the integrally molded body 13 is processed into a predetermined shape, and the rubber roller is completed.

  In the present embodiment, since the variation in the outer diameter between the individual integrally molded bodies 13 is suppressed in the extrusion process, the rubber material 11 is ground under certain conditions for all the integrally molded bodies 13 in the grinding process. be able to. Thereby, a grinding process can be simplified.

  Further, in the extrusion process, the integral molded body 13 is formed so that the integral molded body 13 has an outer diameter close to the outer diameter of the roller portion where the rubber material of the rubber roller after the grinding process is disposed. The amount of the rubber material 11 to be ground can be reduced.

  FIG. 2 is a view showing a rubber roller manufactured by the method of manufacturing a rubber roller according to this embodiment. In this rubber roller, the length of the roller portion 13a on which the rubber material 11 is disposed is 236 mm, and the length of the support portions 13b disposed on both ends of the core metal 12 is 12 mm. This rubber roller exhibited the same performance as that of a rubber roller manufactured using a general extruder.

It is the schematic which showed the structure of the extruder which concerns on the 1st Embodiment of this invention. It is the figure which showed the rubber roller manufactured by the manufacturing method of the rubber roller which concerns on the 2nd Embodiment of this invention. It is the schematic which showed the structure of the extruder relevant to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extruder 2 Crosshead die 2a Die 2b Contact | adherence part 3 Cylinder 4 Screw 6 Core metal supply part 7 Core metal guide 8 Core metal conveyance part 9 Control part 10 Drive part 11 Rubber material 12 Core metal 13 Integrated molding

Claims (7)

A crosshead die, a cylinder communicating with the crosshead die, a screw housed in the cylinder and rotated to supply a rubber material from the cylinder to the crosshead die, and a drive for rotating the screw And a control means for driving the driving means, and a core metal supply means for supplying a core metal to the cross head die, and an integrally molded body of the rubber material and the core metal is formed into the cross head die. Extruder that extrudes from
Measuring means for outputting a measured value of the outer diameter of the integrally molded body extruded from the crosshead die, and calculating means for calculating a rotational speed of the screw at which the measured value becomes a predetermined target value. An extruder in which the control means drives the drive means so that the rotational speed of the screw is the rotational speed calculated by the computing means.   2. The extruder according to claim 1, wherein the cored bar supplying unit includes a cored bar conveying unit that continuously supplies a plurality of the cored bars to the crosshead die.   The extruder according to claim 1, further comprising a temperature control unit that controls the temperature of the crosshead die. A rubber roller and a metal core are supplied to a crosshead die, and a rubber roller manufacturing method including an extrusion process of extruding an integrally molded body of the rubber material and the metal core from the crosshead die,
The extruding step includes a first step of measuring an outer diameter of the integrally molded body extruded from the crosshead die, and a second step of adjusting the outer diameter by controlling a supply speed of the rubber material. A method for manufacturing a rubber roller. Supplying the rubber material from the cylinder to the crosshead die by rotating a screw in a cylinder communicated with the crosshead die;
The second step includes calculating a rotation speed of the screw at which the measured value of the outer diameter becomes a predetermined target value, and rotating the screw at the calculated rotation speed. 5. A method for producing a rubber roller according to 4.   The manufacturing method of the rubber roller of Claim 4 or 5 which supplies the said some metal core continuously to the said crosshead die | dye.   The method for manufacturing a rubber roller according to claim 4, wherein temperature control of the crosshead die is performed.

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