JP2007015044A - Grinding method of rubber covered roll and rubber covered roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain outer diameter deflecting dimensions of a ground rubber covered roll in high precision for a long period of time, to shorten grinding time and to improve a surface property of the outer peripheral surface of the rubber covered roll. <P>SOLUTION: This grinding method of the rubber covered roll to grind an outer peripheral surface of an elastic layer of the rubber covered roll 4 provided with the elastic layer made of a rubber material around a shaft of a core bar shaft 5 by a grinding wheel 6 grinds outer peripheral surfaces on both end parts of the core bar shaft 5 fixed on the rubber covered roll 4 by respectively holding and fixing them by a set of diaphragm type chucks 13, 14 and pressurizing the grinding wheel 6 made wider than length of the outer peripheral surface of the elastic layer in the axial direction along this outer peripheral surface in a state of rotating and driving each of the diaphragm type chucks 13, 14 by synchronizing them. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rubber roll grinding method for grinding rubber rolls such as charging rolls, developing rolls and other various rolls used in electrophotographic apparatuses such as copying machines, laser beam printers and facsimiles.

  In recent years, colorization of electrophotography has progressed, and higher quality such as higher definition and image uniformity (halftone uniformity) has been demanded. For this reason, a cylindrical rubber roll used in an electrophotographic apparatus is required to have high accuracy in outer diameter runout.

  For example, in the charging roll used in the electrophotographic apparatus, when the outer diameter fluctuation of the rubber roll is large, the variation in the width (nip width) that contacts the photosensitive drum during one rotation of the charging roll increases. As a result, the amount of unevenness (circumference unevenness) in which the photosensitive drum is charged during one rotation of the charging roll increases, resulting in an image defect in which unevenness of density occurs on the printed image at the rotation pitch of the charging roll.

  A charging roll used in a typical monochrome print laser beam printer (LBP) tends to cause the above-described image defect when the outer diameter deflection dimension exceeds 0.1 mm. In contrast, charging rolls used in color print LBPs tend to cause image defects when the outer diameter runout exceeds 0.05 mm, so that it is particularly necessary to increase the accuracy of the outer runout dimension. Is done.

  In addition to increasing the accuracy of the outer diameter deflection dimension, it is also important for the electrophotographic apparatus to have very good surface properties with few irregularities present on the outer peripheral surface of the rubber roll. For example, when large irregularities exist on the outer peripheral surface of the charging roll, toner and external additives often adhere. When such toner or the like is accumulated, the ability to charge the photosensitive drum is remarkably reduced, and an image defect occurs. For this reason, in a technique for manufacturing a rubber roll used in an electrophotographic apparatus, it is required to achieve both high accuracy of the outer diameter run-out dimension and improvement of the surface property of the outer peripheral surface.

  Conventionally, grinding is one of the techniques for manufacturing rubber rolls. In the grinding process, the rubber roll is rotated, and a grinding wheel rotated at a relatively high speed is brought into contact with the outer peripheral surface of the rotated rubber roll to perform grinding so that the outer peripheral surface of the rubber roll has a predetermined shape and size. Finished. In the rubber roll grinding device, a grinding wheel with a mechanism of reciprocating a grinding wheel of a width of about 30 mm to 50 mm along the outer peripheral surface of the rubber roll and a grinding wheel of a type whose width is wider than the entire length of the rubber roll. There are some which have a mechanism for grinding in a lump (wide grinding wheel plunge grinding) by abutting them along the outer peripheral surface of the rubber roll.

  In the latter wide whetstone plunge grinding, the contact processing time between the grindstone and the rubber roll per unit time is remarkably increased, so that the grinding processing time can be greatly shortened. Therefore, in recent years, a mechanism using a wide whetstone plunge grinding tends to be generally employed in grinding of a rubber roll used in an electrophotographic apparatus in particular.

  The processing accuracy of the outer diameter runout dimension of the rubber roll after grinding is the same as that of the grinding wheel, in the mechanism that sets the rubber roll, regardless of the width and shape of the grindstone. It has been found that the influence of the accuracy of the rotation, that is, the accuracy of so-called chucking is large. In other words, when grinding is performed with the grinding wheel abutting against the outer peripheral surface while rotating the rubber roll while the amount of fluctuation (rotational runout) of the outer peripheral surface of the rubber roll during rotation is relatively large, the rubber roll after grinding If the outer diameter runout dimension of the rubber roll is increased and the grinding process is performed while reducing the rotational runout of the rubber roll, the outer diameter runout dimension of the rubber roll after grinding tends to be reduced.

  A conventional rubber roll grinding device is a mechanism for setting a rubber roll when grinding the outer peripheral surface of the rubber roll, and a rotation center that rotates and drives the ends of the cored bar shaft protruding from both ends in the axial direction of the rubber roll ( A mechanism (see Patent Document 1) that is pressed and held by a convex part), and the outer peripheral surface of one end side of the cored bar shaft is held and fixed by a collet chuck and the end face corner part of the other end side of the cored bar shaft is fitted. The structure (refer patent document 2) made to hold | maintain so that it can rotate is disclosed. In addition to these, there is a mechanism for holding and fixing the outer peripheral surface of one end side of the core metal shaft with a collet chuck and pressing and holding the other end side of the core metal shaft with a rotation center.

  A state in which a rubber roll to be ground is gripped and fixed in a conventional rubber roll grinding method will be described. FIG. 2 is a schematic diagram for explaining a state in which a rubber roll is set in a conventional rubber roll grinding method.

  In the conventional rubber roll grinding method, as shown in FIG. 2, the outer peripheral surface on one end side of the core metal shaft 105 of the rubber roll 104 is clamped by the head stock side collet chuck 101 of the grinding device, while the core metal shaft 105 The C surface of the end face corner portion on the other end side is pressed by the concave portion which is the tail stock side reverse center 103. In the case of a configuration in which a center hole is provided in the end face of the cored bar shaft 105, it may be configured to be pressed down with a center shape (a convex portion that holds the center hole) instead of the reverse center (a concave portion) described above. Good.

  With the cored bar shaft 105 gripped and fixed in this way, the head stock side rotating flange 102 to which the head stock side collet chuck 101 is attached is driven to rotate by the head stock side motor 107, and the tail stock side reverse center is provided. As the roller 103 is driven to rotate, the rubber roll 104 is rotated at a predetermined rotational speed. Then, in a state where the rubber roll 104 is driven to rotate, the disk-shaped grindstone 106 having a width wider than the entire length in the axial direction of the rubber roll 104 is rotated at a high speed, and the grindstone 106 is pressed against the outer peripheral surface of the rubber roll 104. Grinding is performed.

  At this time, as the speed at which the grindstone 106 is pressed against the outer peripheral surface of the rubber roll 4, that is, the feed amount of the grindstone 106 is increased, the amount by which the rubber roll 104 is pushed and bent by the grindstone 106 increases. The outer diameter of the tail stock side reverse center 103 is smaller than the outer diameter of the head stock side collet chuck 101. The head stock side collet chuck 101 grips and fixes the outer peripheral surface of the cored bar shaft 105, whereas the tailstock side reverse center 103 is formed at an end surface corner on the other end side of the cored bar shaft 105. It only receives and holds the C surface (chamfered surface).

  For this reason, the rubber roll 104 has a relatively large difference in rigidity at both ends of the core metal shaft 105 in a set state in which both ends of the core metal shaft 105 are held and fixed. In order to increase the rigidity of the rubber roll 104 on the tail stock side reverse center 103 side, when the pressing force for gripping and fixing the other end side of the core metal shaft 105 is increased, the core metal shaft 105 is bent, The rubber roll 104 swings and rotates. Since the outer diameter runout dimension of the rubber roll 104 ground in such a rotating state becomes large, there is an upper limit for increasing the pressing force held by the tailstock-side reverse center 103.

  When the grinding wheel 106 is pressed against the outer peripheral surface of the rubber roll 104 due to the difference in rigidity generated at both ends of the core metal shaft 105 in a state where the core metal shafts 105 on both ends in the axial direction of the rubber roll 104 are set. The amount by which the rubber roll 104 is pushed and bent away from the grindstone 106 causes a difference in the axial direction of the rubber roll 104. That is, since the tailstock side reverse center 103 side having a low rigidity is bent greatly, the ability of the grindstone 106 to grind the rubber roll 104 is lowered and the grinding is not sufficiently performed.

  Furthermore, when the speed at which the grindstone 106 is pressed against the rubber roll 104, that is, the feed amount of the grindstone 106 is increased, the outer diameter of the rubber roll 104 after the grinding process also varies in the axial direction. Even if there is no difference in the outer diameter of the rubber roll 104, the difference in the axial direction of the rubber roll 104 occurs in the transition of the outer diameter of the rubber roll 104 up to the finishing stage of the grinding process. A difference occurs in the surface roughness in the axial direction on the outer peripheral surface of the rubber roll 104 after grinding.

  A mechanism in which the head stock side collet chuck 101 holds and fixes one end of the cored bar shaft 105 will be described. The head stock side collet chuck 101 is connected to a draw bar (not shown) provided through the inside of the head stock table 108 and the head stock side rotation flange 102. By pulling the draw bar, the head stock side collet chuck 101 is drawn into a sleeve (not shown) inside the head stock side rotation flange 102, and the taper surface of the head stock side collet chuck 101 and the taper surface of the sleeve are brought together. In addition, since slits that divide at equal intervals in the circumferential direction are formed (generally, there are many three divisions), the inner diameter of the cored bar insertion hole is gradually reduced, and the outer peripheral surface of the cored bar shaft 105 is Hold and fix.

Usually, the collet chuck has a cemented carbide chip attached to a gripping part that grips the cored shaft, so that wear of the gripping part is suppressed and durability is improved. Further, the core metal shaft of the rubber roll used in the electrophotographic apparatus is often made of free-cutting steel, and even when the gripping operation is repeated, scars are hardly generated in the gripping portion of the collet chuck. On the other hand, the outer peripheral taper surface of the collet chuck is hardened so that the hardness is lower than that of the sleeve taper surface, and as the gripping operation is repeated, sliding scratches are gradually generated on the outer peripheral taper surface. And proceed. Therefore, the durability of the collet chuck is determined because the gripping accuracy is lowered due to the influence of the sliding scratches on the outer peripheral tapered surface.
Japanese Patent Laid-Open No. 11-99451 JP 2003-225860 A

  As described above, when performing wide whetstone plunge grinding, the grinding resistance becomes very large. Therefore, when the speed at which the grindstone is pressed against the rubber roll (the feed amount of the grindstone) is increased, the grindstone becomes a rubber roll during grinding. The pressing force with which the grindstone pushes the rubber roll becomes larger than the force for grinding the. In this case, in the mechanism in which both ends of the core metal shaft are pressed and supported by the rotation center (convex portion), if the pressing force for holding and fixing the grindstone against the pressing force for pushing the rubber roll is increased, the core metal shaft is greatly bent. Therefore, the outer diameter runout dimension of the rubber roll after grinding becomes very large.

  Further, as in Patent Document 2, etc., the outer peripheral surface on one end side of the cored bar shaft is held and fixed by a collet chuck and pressed by a mechanism or a rotation center for fitting the end face corner part on the other end side of the cored bar shaft. With the holding mechanism, sliding scratches occur between the collet chuck and the taper surface of the sleeve during continuous processing, and metal powder and grinding rubber powder from the scratch are sandwiched between the taper surfaces, and the accuracy of gripping by the collet chuck is improved. This greatly deteriorates and the outer diameter runout dimension of the rubber roll after grinding becomes large. When such a phenomenon occurs, the collet chuck must be once removed from the sleeve to clean and maintain the tapered surface. Further, if the taper surface is severely damaged, the collet chuck or the sleeve itself must be replaced. As the gripping accuracy is increased, the frequency of periodic cleaning of the tapered surface of the collet chuck increases and the replacement cycle of the collet chuck and the sleeve becomes shorter.

  On the other hand, in the grinding process, the rubber material is scraped off with a grindstone, so that the surface property of the ground surface of the rubber roll tends to be inferior to the surface property of the rubber roll molded by the molding die. For this reason, conventionally, grinding has been mainly used for processing sponge-type rubber rolls and solid-type rubber rolls whose surface properties are not required with relatively high accuracy.

  In particular, when plunge grinding is performed with a wide grindstone, the grinding time can be significantly shortened, but the load on the grindstone increases and the grinding resistance becomes very large. For this reason, if the speed at which the grindstone is pressed against the rubber roll (when the feed amount of the grindstone is increased) is increased, the pressing force with which the grindstone pushes the rubber roll is greater than the force with which the grindstone grinds the rubber roll during grinding. Become. In this case, the mechanism that presses and holds both end portions of the cored bar shaft at the rotation center is too small in rigidity, so that it is pushed and deflected away from the grindstone that is pressed over the entire axial direction of the outer peripheral surface of the rubber roll. The surface property is deteriorated in the entire axial direction of the outer peripheral surface without being sufficiently ground.

  Also, with the mechanism that holds and fixes one end of the core metal shaft with the collet chuck and presses the other end side of the core metal shaft with the rotation center, the rigidity on the rotation center side is smaller than the collet chuck side. It is pushed and bent in the direction away from it, and the surface property deteriorates due to insufficient grinding, and surface property unevenness occurs in the axial direction (longitudinal direction) of the rubber roll on the collet chuck side and the rotation center side. End up.

  Further, in the electrophotographic apparatus, in order to improve the image quality, the rubber roll is required to have a higher function, and the rubber materials used for the rubber roll have been diversified. In particular, in a color print high-quality electrophotographic apparatus, a solid type rubber roll tends to be used more frequently than a sponge type rubber roll. Many solid-type rubber rolls have low grindability, such as silicone rubber and urethane rubber, which generate heat due to friction with the grinding wheel during grinding. In addition, in terms of the blending of the rubber material, when the blending ratio of the polymer is large and the blending ratio of the filler such as carbon black or calcium carbonate is decreased, the grindability is greatly lowered.

  When grinding a solid type rubber roll or a rubber roll with reduced grindability on the compounding surface with a wide type grinding wheel plunge grinding machine, the conventional rubber roll setting mechanism causes the grinding wheel to be rolled into the rubber roll due to the effect of the rubber roll grinding resistance that increases significantly. When the speed of pressing against the roller, that is, the feed amount of the grindstone is increased, the surface property of the outer peripheral surface of the ground rubber roll is greatly deteriorated. For this reason, it is very difficult to maintain or improve the surface properties of the grinding surface and shorten the grinding time, which has been a big problem.

  Therefore, the present invention makes it possible to hold the outer peripheral surfaces of the both ends of the cored bar shaft with high accuracy and sufficient rigidity, and to rotate and rotate the both ends of the cored bar shaft in a synchronized manner. Rubber roll grinding method capable of maintaining the outer diameter runout dimension of the rubber roll with high accuracy over a long period of time, reducing the grinding time and improving the surface properties of the outer peripheral surface of the rubber roll after grinding, and this grinding An object of the present invention is to provide a rubber roll ground by the method and a rubber roll grinding apparatus.

  In order to achieve the above-described object, the rubber roll grinding method according to the present invention comprises grinding a rubber roll by grinding an outer peripheral surface of the elastic layer of the rubber roll provided with an elastic layer made of a rubber material around the axis of the core metal shaft. The outer peripheral surface of both ends of the metal core shaft is held and fixed by a pair of diaphragm chucks, and the shafts of the outer peripheral surface of the elastic layer are rotated in synchronization with each diaphragm chuck. Grinding is performed by pressing a grindstone wider than the length in the direction over the outer peripheral surface.

  As described above, according to the present invention, the rotation accuracy of the rubber roll during grinding can be maintained with high accuracy, and a rubber roll with a very high outer diameter runout after grinding can be obtained over a long period of time. It becomes possible. Furthermore, in the present invention, the outer peripheral surfaces of both ends of the core metal shaft are held and fixed by a pair of diaphragm chucks, thereby improving the rigidity in the set state of the rubber roll and the rigidity at both ends of the core metal shaft. Can be made substantially equal, the grinding time can be shortened, and the surface properties of the outer peripheral surface of the ground rubber roll can be improved.

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

  FIG. 1 is a schematic diagram illustrating a state in which a rubber roll is set in a grinding apparatus in the rubber roll grinding method of the present embodiment.

  The rubber roll used in this embodiment is provided with a cylindrical elastic layer made of vulcanized rubber fixed around the axis of the core metal shaft. Both ends of the cored bar shaft protrude from both ends of the rubber roll in the axial direction.

  As shown in FIG. 1, the rubber roll grinding apparatus includes a grindstone driving mechanism 2 for rotating a grindstone 6 formed wider than the axial length of the rubber roll 4 and pressing the grindstone 6 against the outer peripheral surface of the rubber roll 4, and a rubber roll. A pair of headstock-side diaphragm chuck 13 and tailstock-side diaphragm chuck 14 that hold and fix both ends of the four cored bar shafts 5, and these headstock-side diaphragm-type chuck 13 and tailstock-side diaphragm-type chuck 14 The head stock side motor 7 and the tail stock side motor 15 that are driven to rotate in synchronization with each other are provided.

  The grindstone driving mechanism 2 is arranged such that the axial direction of the grindstone 6 to be rotationally driven is parallel to the axial direction of the rubber roll 4 to be rotated. Although not shown, the grindstone driving mechanism 2 includes a motor that rotationally drives the cylindrical grindstone 6, and a moving mechanism that presses the peripheral surface of the grindstone 6 against the outer peripheral surface of the rubber roll 4.

  In the rubber roll 4, the outer peripheral surface on one end side of the cored bar shaft 5 is clamped by the head stock side diaphragm chuck 13 of the grinding device. The rubber roll 4 is similarly clamped on the outer peripheral surface of the other end side of the cored bar 5 by a tailstock side diaphragm chuck 14 of the grinding device.

  The tailstock-side diaphragm chuck 14 is moved forward in two stages in the axial direction by two cylinders (not shown), so that the gripping amount in the axial direction of the core metal shaft 5 is reduced to the headstock-side diaphragm chuck 13. This is the same as the gripping amount of the cored bar shaft 5. The head stock side diaphragm chuck 13 and the tail stock side diaphragm chuck 14 that are opposed to each other are arranged so that both ends of the core metal shaft 5 can be held and fixed on a coaxial core in which the shaft cores coincide with each other.

  In this gripping state, the head stock side diaphragm chuck 13 is configured to be rotationally driven at a predetermined rotational speed by the head stock side motor 7. Similarly, the tailstock-side diaphragm chuck 14 is configured to be rotated at a predetermined rotational speed by the tailstock-side motor 15. Since the head stock side motor 7 and the tail stock side motor 15 are controlled by a control circuit unit (not shown) so as to rotate and synchronize with each other, a twisting force acts around the axis of the cored bar shaft 5. Never do. Then, as in the conventional grinding apparatus, while the rubber roll 4 is rotated, the grindstone 6 wider than the entire length of the rubber roll 4 is rotated at a high speed, and the grindstone 6 is pressed against the outer peripheral surface of the rubber roll 4 and pushed. Apply the grinding process.

  A mechanism for gripping and fixing both end portions of the core metal shaft 5 for the diaphragm chucks 13 and 14 will be described. Hereinafter, the headstock diaphragm type chuck 13 will be described. Note that the tailstock-side diaphragm chuck 14 has the same configuration as that of the headstock-side diaphragm chuck 13, and thus the description thereof is omitted.

  The headstock diaphragm chuck 13 is attached to the chuck adapter 10 with the chuck pawl 12 attached to the tip of the nose 11. The chuck claw 12 is divided into a plurality of parts by forming a plurality of slits up to the vicinity of the base attached to the nose 11 (generally, there are many from 6 to 8 divisions), and the nose 11 is equally spaced from each other. It is arranged and attached along the circumference.

  In addition, an air supply tube (not shown) is provided in the headstock base 8 and the chuck adapter 10 so as to penetrate the nose 11 by the pressure of the air. The central portion of a diaphragm (not shown) provided on the inner surface is pressed to bend and deform, thereby opening and closing the chuck claw 12 to grip and fix the outer peripheral surface of the cored bar shaft 5. Although not shown, another configuration may be adopted in which the chuck pawl is opened and closed by joining the piston to the diaphragm and pressing and deforming the central portion of the diaphragm with the piston.

  Normally, the chuck claw of a diaphragm chuck has a gripping part that grips and fixes the core metal shaft in a slightly gentler arc than the arc formed by the outer diameter of the core metal shaft, and the center of the chuck claw is centered. The holding force for holding the metal shaft is accurately transmitted. In the rubber roll grinding method of the present invention, it is more preferable that the chuck claws 12 of the diaphragm chucks 13 and 14 for gripping and fixing the outer peripheral surface of the core metal shaft 5 are divided into any one of 6 divisions to 8 divisions. As a result, the contact points between the chuck claws and the outer peripheral surface of the core metal shaft are increased, and a holding force is evenly applied at each contact point, and the accuracy of gripping and fixing the outer peripheral surface of the core metal shaft is further improved. In addition, the initial accuracy in the gripping accuracy of the diaphragm chuck is superior to that of the collet chuck, so that the deflection accuracy of gripping and fixing the core metal shaft is very high.

  Further, although not shown in the drawings, the diaphragm chucks 13 and 14 for gripping and fixing the outer peripheral surfaces of both ends of the core metal shaft 5 used in the rubber roll grinding method of the present embodiment, A discharge hole for discharging air is provided. Diaphragm chucks 13 and 14 are fed with pressure from a pipe passing through the inside of the chuck adapter 10 and the nose 11, and are fed by a discharge hole from the inside of the core shaft insertion hole toward the grip portion of the core shaft 5. The structure which discharge | releases is taken. For this reason, according to the rubber roll grinding method of the present embodiment, grinding rubber powder or dust generated during grinding of the rubber roll 4 enters between the inside of the chuck claw 12 and the outer peripheral surface of the core metal shaft 5. A reduction in gripping accuracy is prevented.

  Further, in the diaphragm chuck used in the rubber roll grinding method of the present invention, since a cemented carbide chip (not shown) is attached to the gripping portion of the core metal shaft 5 in the chuck claw 12, the core metal shaft 5 is gripped. Even if the operation is repeated, the outer peripheral surface of the cored bar 5 is prevented from being damaged. Diaphragm chucks do not use taper surface alignment like collet chucks, so there is a decrease in gripping accuracy caused by taper surface alignment such as generation of scratches on the taper surface and entry of foreign matter. Does not occur. Further, in the conventional grinding method, when the accuracy is lowered, it is necessary to periodically remove the collet chuck and clean and maintain the tapered surface. However, in the grinding method of the present invention, a diaphragm chuck is used. As a result, regular cleaning and maintenance becomes unnecessary.

  In the rubber roll grinding method of the present invention, each of the diaphragm chucks 13 and 14 serves as a mechanism for setting the rubber roll 4, and the outer peripheral surface of the core metal shaft 5 is axially oriented at both ends of the core metal shaft 5. Since the inner diameters of the diaphragm chucks 13 and 14 that are gripped and fixed at the same gripping amount are the same at both ends of the cored bar shaft 5, the cored bar shaft 5 is held. The rigidity at is very high, and there is no difference at both ends of the cored bar shaft 5. For this reason, when the grindstone 6 is pressed against the outer peripheral surface of the rubber roll 4, the amount that the rubber roll 4 is deflected in the direction away from the grindstone 6 is very small, and there is no difference between both ends of the cored bar shaft 5. Even under these grinding conditions, the amount of rubber to be ground can be greatly increased.

  Therefore, even when the speed at which the grindstone 6 is pressed against the rubber roll 4, that is, when the feed amount of the grindstone 6 is increased, the rubber roll 4 is sufficiently ground, and the rubber roll 4 having a very excellent outer surface is obtained. Processing time can be greatly shortened. Further, since the outer peripheral surfaces of both ends of the core metal shaft 5 are gripped and fixed, there is no need to provide a center hole on the end surface of the core metal shaft 5, and the chamfering of the C surface at the end surface corner of the core metal shaft 5 is also burr. High machining accuracy is not required because simple machining is required. Therefore, the processing cost of the cored bar is reduced, and as a result, the processing cost of the rubber roll is reduced.

  As described above, according to the rubber roll grinding method of the present embodiment, the rotation accuracy of the rubber roll 4 at the time of grinding can be maintained with high precision, and the outer diameter runout dimension after grinding is extremely high precision. Can be obtained over a long period of time. Further, the rigidity of the rubber roll 4 in the set state is improved by gripping and fixing the outer peripheral surfaces of both ends of the core metal shaft 5 with a pair of diaphragm chucks 13 and 14. Can be made substantially equal in rigidity, the grinding time can be shortened, and the surface properties of the outer peripheral surface of the ground rubber roll 4 can be improved.

  The rubber roll grinding method according to the present invention is a rubber roll in which an elastic layer made of vulcanized rubber is provided around the axis of the core metal shaft, particularly hydrin rubber, silicone rubber, nitrile rubber (NBR), ethylene-propylene trimer. When the so-called solid type rubber roll having an elastic layer made of a body (EPDM) and urethane rubber or the like is ground, the above-described effects can be obtained more favorably. In addition, the rubber roll grinding method according to the present invention includes a rubber roll having a particularly smooth surface and a rubber roll for electrophotography (for example, a charging roll or a developing roll) provided with a surface layer by coating the surface. Also when grinding, it is preferable because the above-described effects can be obtained more satisfactorily.

  Hereinafter, specific examples of the present invention will be described.

[Production method of rubber roll before grinding]
A rubber material containing 100 phr of epichlorohydrin rubber, 10 phr of plasticizer, 5 phr of carbon black, 30 phr of calcium carbonate, 2 phr of sulfur, and 1 phr of mercaptobenzothiazole is kneaded by using a closed kneader and a roll machine, and unvulcanized rubber. A composition was obtained.

  Simultaneously extruding the above-mentioned unvulcanized rubber composition with an extruder, the core metal shaft is continuously passed through the crosshead die of the extruder, and the unvulcanized rubber composition is formed on the outer peripheral surface of the core metal shaft. After placing the product in a roll shape, the rubber roll before grinding in which an elastic layer made of vulcanized rubber is formed around the axis of the cored bar shaft is vulcanized by placing it in a hot air oven at 200 ° C. for 20 minutes. It was.

[Rubber roll external dimensions and grinding conditions]
Metal core shaft: total length 250mm, outer diameter φ6.0mm
Rubber roll: rubber surface length 230mm, outer diameter φ13.5mm,
Protrusion from each end face of rubber roll of core metal shaft: 10mm each
Finished outer diameter of rubber roll: φ12.0mm
Grinding conditions: Wide grinding wheel plunge grinding Grinding wheel diameter: φ200mm
Wheel rotation speed: 2800 rpm
Number of revolutions of rubber roll: 300 rpm
Grinding time: 30 seconds [Comparative example and Example]
Comparative example: The outer peripheral surface of one end of the core shaft of the rubber roll is clamped by a head stock side collet chuck with a length of 5 mm in the axial direction, and the C surface of the end surface corner of the other end of the core shaft is tailed. In a state where the rubber roll was rotated by pressing the stock side reverse center and rotating the head stock side rotation flange, the grindstone was pressed against the rubber roll for grinding.

  Example: The outer peripheral surface of one end side of the core metal shaft of the rubber roll is clamped by a head stock side diaphragm chuck with a length of 5 mm, and the outer peripheral surface of the other end side of the core metal shaft is 5 mm long with a tail stock side diaphragm chuck Then, both ends of the cored bar shaft were rotated while being synchronized, and the grindstone was pressed against the rubber roll in such a rotated state to grind the rubber roll. The diaphragm chuck used had a diaphragm diameter of 4 inches and a chuck claw length of 15 mm.

  Table 1 shows the results of measurement of the outer diameter runout dimensions of the initial grinding and the 50,000, 100,000, and 200,000 rubber rolls when continuously grinding by the grinding methods of the comparative example and the example described above. Shown in

  When continuous grinding is performed with the grinding method of the comparative example, the outer diameter runout dimension of the rubber roll after grinding at the beginning of the start was 0.022 mm, whereas the outer runout dimension after grinding 200,000 pieces. Since it deteriorated to 0.050 mm, the collet chuck was removed from the rotating flange for cleaning maintenance.

  On the other hand, when continuous processing is performed by the grinding method of the embodiment of the present invention, the outer diameter runout dimension of the rubber roll after grinding at the beginning of the start was 0.014 mm, whereas the outer diameter after grinding 200,000 pieces The radial runout remained as good with almost no change of 0.018 mm.

  On the other hand, with respect to the surface roughness of the outer peripheral surface of the rubber roll ground by the grinding method of the comparative example and the example described above, the results of measuring the center part, the head stock side end part, and the tail stock side end part, respectively. It shows in Table 2.

  As shown in Table 2, in the grinding method of the comparative example, the surface roughness of the rubber roll after grinding is the largest at Rz 10.25 μm, and then the tail stock side end is relatively large at Rz 6.73 μm. The head stock side end was the smallest at Rz 3.26 μm. Regarding the longitudinal unevenness of the surface roughness, the difference between the center portion and the head stock side end portion was 6.99 μm.

  In contrast, in the grinding method of the embodiment according to the present invention, the surface roughness of the rubber roll after grinding is the largest at Rz 3.43 μm, the head stock side end is Rz 2.98 μm, and the tail stock side end is The portion became Rz 3.10 μm, and the uniformity was improved. The longitudinal unevenness of the surface roughness was 0.45 μm in the difference between the central portion and the head stock side end portion, and could be greatly reduced.

In the rubber roll grinding method of this embodiment, it is a schematic diagram explaining the state by which the rubber roll was set when grinding a rubber roll. In the conventional rubber roll grinding method, when grinding a rubber roll, it is a schematic diagram explaining the state by which the rubber roll was set.

Explanation of symbols

4 Rubber Roll 5 Core Bar 6 Grinding Wheel 12 Chuck Claw 13 Head Stock Side Diaphragm Chuck 14 Tail Stock Side Diaphragm Chuck

Claims (7)

A rubber roll grinding method for grinding an outer peripheral surface of the elastic layer of a rubber roll provided with an elastic layer made of a rubber material around an axis of a core metal shaft with a grindstone,
The outer peripheral surfaces of both ends of the cored bar shaft are held and fixed by a pair of diaphragm chucks, and the diaphragm chucks are driven to rotate in synchronization with each other. A method of grinding a rubber roll, wherein the grinding wheel having a width wider than the length of the grinding wheel is pressed over the outer peripheral surface for grinding.   The method of grinding a rubber roll according to claim 1, wherein when grinding the rubber roll, air is blown from the inside of the diaphragm chuck toward a holding portion that holds the core shaft.   The rubber roll according to claim 1 or 2, wherein each diaphragm chuck has a chuck claw in which a holding portion for holding the cored bar is divided into at least six parts, and a cemented carbide chip is provided on the holding portion. Grinding method.   At least one of the diaphragm chucks changes the gripping amount in the axial direction of the core metal shaft in a plurality of stages so that the gripping amounts at both ends of the core metal shaft held by each diaphragm chuck are substantially equal. The method for grinding a rubber roll according to any one of claims 1 to 3.   A rubber roll manufactured using the rubber roll grinding method according to claim 1 and used in an electrophotographic apparatus.   The rubber roll according to claim 5, wherein a surface layer is provided on an outer peripheral surface of the elastic layer by performing a coating process. A rubber roll grinding device for grinding an outer peripheral surface of the elastic layer of a rubber roll provided with an elastic layer made of a rubber material around a shaft of a core metal shaft,
A pressing means for pressing the grindstone, which is wider than the axial length of the outer peripheral surface of the elastic layer, over the outer peripheral surface;
A pair of diaphragm chucks for holding and fixing the outer peripheral surfaces of both ends of the cored bar;
A rubber roll grinding device comprising: driving means for synchronously rotating the diaphragm chucks.

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