JP2006305770A - Rubber roll and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a rubber roll showing a relation of end part outer diameter less than central part outer diameter constituted so as to solve the problem related to the altering labor of a grindstone shape corresponding to the switching of a product in a grinding process, a grinding time required per one rubber roll and rubber refuse occurring by grinding, requiring no grinding process becoming a post-process or capable of reducing the grinding amount in the grinding process, and the rubber roll manufactured by this manufacturing method. <P>SOLUTION: In the manufacturing method of the rubber roll showing the relation of end part outer diameter<central part outer diameter having an extrusion process of the rubber roll for passing a core metal through a crosshead die and supplying a rubber material to the outer periphery of the core metal by an extruder and a process for cutting the rubber roll into the length of the core metal, the pressure of rubber and a close adhesion section are increased and decreased by sliding the core metal guide enclosed in the crosshead die forward and rearward through a section where the core metal is brought into close contact with the rubber material in an area where the core metal is covered with the rubber material and the rubber roll is extruded while varying the outer diameter of an extruded roll. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a rubber roll having an outer diameter of an end portion <an outer diameter of a central portion used for a paper feed roll, a charging roll, a transfer roll, a developing roll, a toner supply roll, a cleaning roll, etc. incorporated in a copying machine or a printer And a rubber roll.

  In a method of manufacturing a rubber roll having a shape of the outer diameter of the end portion <the outer diameter of the central portion using a general crosshead extruder, the molding method in which the rubber compound is coated while continuously inserting the core metal, 2. A cored bar (3) in which an adhesive primer, whose position is determined by a cored bar guide (4), is pre-coated at the central part where rubber is extruded in a cylindrical shape in the extruder head (1) as shown in FIG. Is fed intermittently and at a constant speed by the core metal feed roll (2), the rubber material (6) supplied at a constant speed amount to the outer periphery of the core metal in the core metal-rubber adhesion area (8). It is covered integrally. The core-rubber columnar body extruded from the extruder head end cap (7) through the coating area is separated to the length of each roll by a take-off cutting machine attached to the extruder.

  Furthermore, in such roll production, as a subsequent process, a cylindrical work having a roll length for each roll is continuously conveyed in a hot stove by a conveyor. After the vulcanization reaction is performed, the rubber is cut into a necessary rubber length and is carried to a grinding process for processing into an outer diameter size and a required outer diameter size and shape.

  In the grinding process, the cutting rotary grindstone having a width exceeding the rubber length is pressed against the work rotated at a constant speed, and the work is cut to a required outer diameter. At this time, the grinding wheel to be pressed is processed into the shape required for the product. Generally, when creating a rubber roll in which the outer diameter of the end portion is smaller than the outer diameter of the central portion, the outer diameter increases from the end portion to the central portion. The grindstone is dressed so that it has a simple crown shape or a tapered shape in several steps from the end to the center.

  However, in this grinding process, a cylindrical workpiece can be machined with high precision, but the labor of changing the shape of the grindstone corresponding to product switching, the grinding time required for each piece, and the rubber residue generated by grinding are made of material. This leads to inefficiency in use and causes disposal problems.

Also, when creating a crown-shaped rubber roll using a crosshead extruder, the rubber supply amount is controlled by the screw speed of the extruder, the speed at which the core metal is fed is controlled, and the rubber is crown-shaped. A method of adhering to the surface has been reported (for example, see Patent Document 1). However, the control of the rubber supply amount with a screw is greatly influenced by the characteristics of the rubber compound used, the extruder and the screw shape specification, and it is difficult to achieve the high accuracy expected from the control time difference. The means for changing the feeding speed of the cored bar is not suitable for high accuracy because it is difficult to always maintain the speed control of the cored bar even in the head.
JP 2004-145012 A

  Therefore, the present invention is to find a solution to the trouble of changing the shape of the grindstone corresponding to the product switching in the grinding process, the grinding time required per one, and the problem of rubber residue generated by grinding, Provided is a method of manufacturing a rubber roll that does not require a grinding step that is a subsequent step or that can reduce the amount of grinding in the grinding step, and a rubber roll that is produced by the method, and a rubber roll made by the method. With the goal.

Further, the present invention provides a method of manufacturing a rubber roll in which the outer diameter of the end portion is smaller than the outer diameter of the central portion by a relatively easy device mechanism without controlling the supply amount of the rubber compound by rotating the screw or controlling the supply speed of the cored bar. There is.
In addition to adjusting not only the rubber pressure, but also the speed at which the mandrel guide is slid, the roller shape can be controlled more effectively, and a rubber roll manufacturing method in which the outer diameter of the end portion is smaller than the outer diameter of the central portion is provided. is there.

  The object of the present invention is achieved by the following.

  Extrusion step of a rubber roll in which a core metal is passed through a crosshead die and a rubber material is supplied onto the outer periphery of the core metal by a rubber extruder, and an outer diameter of the end including a step of cutting the rubber roll into the length of the core metal <In the rubber roll manufacturing method to be the outer diameter of the central part, by reducing the rubber pressure at the end part forming part of the rubber roll in the rubber roll extruding step and increasing it at the central part forming part, the outer diameter of the extruded roll is changed, The rubber roll manufacturing method is characterized in that the outer diameter of the end of the rubber roll is smaller than the outer diameter of the center.

  Further, in the present invention, by using the above molding method, the shape of the rubber roll is molded into a rubber roll having an outer diameter difference of 0.1 to 1.0 mm in one longitudinal length and an outer diameter of the end portion <the outer diameter of the central portion. Is achieved.

  As mentioned above, the rubber roll is extruded while changing the outer diameter of the roll to be extruded by increasing / decreasing the rubber pressure and the rubber contact section in the area where the core is covered with rubber by sliding back and forth of the core metal guide. Thus, the shape of the extruded rubber roll can be processed into a rubber roll having an outer diameter difference of 0.1 to 1.0 mm in the length of one roll in the longitudinal direction and an outer diameter of the central portion <the outer diameter of the central portion. Even if no process is required, a rubber roll having the same dimensional accuracy can be obtained. Therefore, no grinding process is required and no rubber residue is generated.

  The core metal used in the present invention may be a known material that is usually used as a core metal for a roll. In particular, a metal such as iron or aluminum or a material plated thereon is used, and a primer is preferably applied so that the core metal and the rubber component are sufficiently bonded.

  Examples of rubber materials used in the present invention include those known as roll materials, such as nitrile butadiene rubber, hydrides, epichlorohydrin rubber, styrene butadiene rubber, polybutadiene rubber, EPM, EPDM, silicone rubber, urethane rubber, and mixtures thereof. Illustrated. In addition to the rubber material, a vulcanizing agent, a vulcanization accelerator, a conductive agent, a charge control agent, a stabilizer, an ultraviolet absorber, an antistatic agent, a reinforcing agent, a lubricant and the like may be added as necessary.

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

  In the rubber roll manufacturing method according to the present invention, a crosshead type extruder capable of continuously covering a rubber compound and a core metal is used, and a primer mainly composed of a resin is used in order to adhere to the rubber part. The coated metal core (3) is supplied to the metal core guide (4) using a metal core feed roll (2) that intermittently supplies the metal core.

  The cross-head extruder has a head for covering the core metal with rubber by passing the core metal perpendicularly to the rubber extrusion direction at the tip of a uniaxial rubber extruder with a screw diameter of 30 to 90 mm. Use a metal core with a length of 200 to 350 mm.

  The core metal (3) is covered with a rubber compound in a core metal-rubber adhesion area (8) inside the crosshead die (1), and is extruded in a roll shape from the cylindrical die (7).

  At this time, the distance between the metal core guide tip, which is the length of the rubber-coated area (8) to the metal core, and the die is short when the end portion of one roll length is extruded, and it is in the center of one roll. It gets longer as you go. Then, it increases / decreases so that it becomes short again toward an edge part. As a result, the pressure of rubber in the rubber covered area increases and decreases, and the outer diameter of the rubber roll extruded from the base changes.

  By making this change in distance constant by the forward / backward slide operation of the core bar guide (4), the extruded workpiece has a thin outer diameter at the end, the outer diameter increases toward the center, and passes the center. A rubber coating process is obtained in which the outer diameter decreases toward the end.

  The slide of the mandrel guide is driven by programmed electrical control of the rear mechanical mechanism (11) (12) (not shown) that allows the mandrel guide to move back and forth in a certain cylinder. The outer diameter of the roll can be controlled by a program along with the feed speed of the roll.

  In this way, a workpiece coated with rubber at a desired end outer diameter <center outer diameter is heat-treated in a hot-air vulcanizing furnace and cut into a necessary rubber length to obtain a rubber roll product.

  The roll of the present invention may have a single layer structure or a laminated structure. The roll of the present invention can be used as an electrophotographic developing roll, a charging roll, a transfer roll, and the like.

  Examples of the present invention will be specifically described below.

  The metal core used as the shaft body was prepared by extruding an iron material into a bar with a diameter of about 6 mm by extrusion, cutting it to a length of 258 mm, and then applying chemical plating to this to a thickness of about 3 μm.

  A hot melt type conductive primer mainly composed of a styrene resin was applied to the core metal uniformly with a thickness of about 10 μm except for 14 mm from the end.

  The core metal is conveyed to a rubber coating area inside the cross head by a core metal supply device attached to the extruder head and a core metal guide in the cross head die.

  The extruder is a uniaxial vent type extruder with a φ60mm screw, equipped with a crosshead type cored bar and rubber coating function, the die diameter of the rubber protruding part is φ11.5mm, and the temperature of the entire head is adjusted to about 40 ° C .

  The metal core guide for conveying the metal core into the cross head has a ball screw at the rear end and a mechanism for sliding back and forth 35 mm in the metal core feed direction by motor torque, and its drive control is based on an electrical program.

  A rubber compound containing EPDM as the main component and kneaded various fillers, plasticizers, reinforcing agents, and vulcanizing agents is extruded at a screw speed of 15 rpm, and the core metal is intermittently supplied at 2.0 m / min. did.

  The slide program of the mandrel guide is 3mm from the tip of the die to the tip of the nipple at the end, and then the distance from the tip of the die to the tip of the nipple is 18mm at the center. It set so that it might become.

  Table 1 shows the relationship between the rubber pressure near the screw (9), the rubber pressure near the base (10), and the outer diameter of the rubber roll to be extruded, which accompanies the sliding operation of the core bar guide.

  Actually, there is a certain time difference between the change in rubber pressure and the change in the outer diameter of the extrusion against the back and forth slide of the core bar guide. When one roll is extruded into a crown shape or an outer diameter of the end portion <the outer diameter shape of the center portion, The slide operation is performed by a program that takes into account the time difference.

  The rubber rolls thus extruded are cut one by one by a take-up machine provided side by side, and one roll becomes a rubber roll having an outer diameter end portion <outer diameter central portion, and is vulcanized by a heat treatment in a subsequent process.

  After that, the rubber part of both ends 12mm is cut out to create a rubber roll part consisting of a 12mm cored bar part and a 234mm arc shape at both ends, and it becomes a constant product.

  The outer diameter of the rubber roll thus obtained was measured by a laser length measuring machine while the core metal surface was received by a V-groove and rotated at 10 rpm for 9 seconds, and the average outer diameter at each point of the roll and the radius accompanying the circumferential rotation were measured. Table 2 shows the measured values of runout.

Comparative example

    The metal core used as the shaft body was prepared by extruding an iron material into a bar with a diameter of about 6 mm by extrusion, cutting it to a length of 258 mm, and then applying chemical plating to this to a thickness of about 3 μm.

  A hot melt type conductive primer mainly composed of a styrene resin was applied to the core metal uniformly with a thickness of about 10 μm except for 14 mm from the end.

  The core metal is conveyed to a rubber coating area inside the cross head by a core metal supply device attached to the extruder head and a core metal guide in the cross head die.

  The extruder is a uniaxial vent type extruder with a φ60mm screw, equipped with a crosshead type cored bar and rubber coating function, the die diameter of the rubber protruding part is φ11.5mm, and the temperature of the entire head is adjusted to about 40 ° C .

  A cored bar guide for transporting the cored bar into the cross head is fixed to a position that defines a roll central axis with respect to a cylindrical base for discharging rubber.

  A rubber compound containing EPDM as the main component and kneaded various fillers, plasticizers, reinforcing agents, and vulcanizing agents is extruded at a screw speed of 15 rpm, and the core metal is intermittently supplied at 2.0 m / min. did.

  The rubber rolls extruded in this way are discharged as a cylindrical shape having a constant outer diameter, and are separated one by one by a take-up machine provided therewith.

  This rubber roll is solidified through a vulcanization process by heat treatment, and then a rubber part at 12 mm at both ends and a rubber roll part at 234 mm are created by cutting off the rubber parts at 12 mm at both ends.

  Furthermore, this roll is ground using a grinding wheel having a width of 250 mm and a diameter of about 300 mm. The grinding wheel is dressed in a crown shape with a deep center at 234mm, which is the length of the rubber roll. Cutting to a dimension of 10.0 mm / min was performed, and a desired roll shape was obtained after 10 seconds of squeakout.

  The outer diameter of the rubber roll thus obtained was measured by a laser length measuring machine while the core metal surface was received by a V-groove and rotated at 10 rpm for 9 seconds, and the average outer diameter at each point of the roll and the radius accompanying the circumferential rotation were measured. Table 3 shows the measured deflections.

Schematic diagram of rubber roll manufacturing device with slidable cored bar guide Schematic diagram of rubber roll manufacturing equipment using a conventional crosshead extruder

Explanation of symbols

1. Crosshead 2. 2. Core metal supply roller 3. Primer coated metal core 4. Metal core guide 5. Extruder cylinder Rubber 7. Base die 8 8. Metal core-rubber adhesion area Cylinder internal pressure measuring machine10. 10. Inner pressure measuring machine Slide mechanism screw 12. Slide mechanism motor

Claims (4)

  In a rubber roll manufacturing method, comprising: a step of passing a core metal through a crosshead die, and a step of extruding the rubber roll by supplying a rubber material onto the outer periphery of the core metal by a rubber extruder; and a step of cutting the rubber roll into the length of the core metal In the rubber roll extrusion process, the rubber pressure is decreased at the end forming portion of the rubber roll and increased at the central forming portion, thereby changing the outer diameter of the extruded roll, and the end diameter of the rubber roll <the outer diameter of the central portion. A rubber roll manufacturing method characterized by the above.   In a section in which the core metal and the rubber material are in close contact with each other in the rubber roll extrusion process, the core metal guide included in the crosshead die is slid in the front-rear direction at the end forming portion of the rubber roll with respect to the core metal feed direction. 2. The method of producing a rubber roll according to claim 1, wherein the rubber pressure and the close contact section are gradually increased and decreased by increasing the speed of the pressing and by decreasing the speed at the central portion forming portion.   The rubber roll manufacturing method according to claim 1 or 2, wherein the shape of the rubber roll has an outer diameter difference of 0.1 to 1.0 mm in one roll length, and an end outer diameter <a center outer diameter.   A rubber roll for an electrophotographic apparatus, produced by the production method according to claim 1.

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