JP2012217992A - Method of manufacturing thin wall core metal with rib - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing a thin-wall core metal with ribs having high rigidity.SOLUTION: The ribs on the inner surface of the thin-wall core metal are formed by disposing a core 31, which encloses a hollow cylindrical thin-wall core metal material 62 between a pair of rotating rollers 41 and 51, narrowing the gap between the rotating rollers 41 and 51 while rotating the rollers, and pressing a group of ridges 42 provided to the roller 41 against the thin-wall core metal material 62, thereby transcribing the ridges to the inner surface of the thin-wall core metal material 62. A core 31 is provided with a group of grooves corresponding the group of ridges, and when the group of ridges 42 of the roller are pressed against the thin-wall core metal material 62, the group of grooves of the core 31 is situated to a position corresponding to the group of ridges 42. The operation is repeated required times, and accordingly, the ribs are formed to the inner surface of the thin-wall core metal material at a position corresponding to the grooves of the core 31.

Description

  The present invention relates to a method for manufacturing a thin cored bar having reinforcing ribs on the inner surface, and more particularly to an efficient method for manufacturing a thin cored bar such as an electrophotographic fixing roll cored bar.

  When printing or copying using an image forming apparatus such as an electrophotographic copying machine, a laser printer, or a facsimile, the visible image (toner image) on the transfer material (recording paper) is heated at the final stage. It is fixed on the recording paper by melting. For example, in an electrophotographic copying machine, a process of forming an electrostatic latent image by performing image exposure on an image carrier, a process of forming a visible image by attaching toner to the electrostatic latent image on the image carrier, an image The process of transferring the toner image on the carrier onto the recording paper and separating the recording paper from the image carrier, and fixing the unfixed toner image transferred onto the recording paper on the recording paper by heating and melting. Copying is performed sequentially through the process.

  Conventionally, an unfixed toner image transferred onto a recording sheet is generally fixed by a thermal fixing method. In this thermal fixing system, a fixing roller is used in which a heater such as a halogen lamp is disposed along the rotation axis in a hollow portion of a cylindrical cored bar and heated from the inside of the cylindrical cored bar by its radiant heat. ing. The unfixed toner image is transferred to the recording paper, and while the recording paper passes between the fixing roller and the pressure roller, the transferred toner is heated and melted and pressed onto the recording paper. As a result, the toner image Is fixed on the recording paper.

  In such an image fixing method, while it is strongly desired to shorten the time required for image fixing, it is required to suppress energy consumption as much as possible. For this reason, measures have been taken to reduce the thickness of the fixing roller and accelerate heat transfer from the heat source inside the roller to the surface layer, but simply reducing the thickness reduces the mechanical strength of the fixing roller. Deformation is likely to occur at the time of contact with the pressure roller, and unevenness occurs on the contact surface between the fixing roller and the pressure roller, causing a fixing failure. For this reason, in order to increase the mechanical strength of the fixing roller, conventionally, measures have been taken to provide reinforcing ribs on the inner surface of the core metal.

  For example, Patent Document 1 describes that a spiral rib is formed on the inner surface of a core metal, and Patent Document 2 describes that a circumferential rib is formed evenly on the left and right. . Further, Patent Document 3 discloses that the thin core metal is rotated by rotating the thin core metal while supporting both ends of the hollow cylindrical thin core metal and pressing a pressing member against the surface of the thin core metal. A method for forming ribs at a plurality of locations in the axial direction is described. According to Patent Document 3, the rib is formed by pressing a thin cored bar material while rotating a spinning roller (see FIG. 13 of Patent Document 3) having a pressing width corresponding to the rib width. Since this spinning roller has a tip corresponding to the width of one rib, there is only one rib that can be formed by a single press-working operation. There is a problem that it is necessary to repeat the pressing process, which is complicated and requires a long time for the process.

  Patent Document 3 also discloses a method of disposing a backup roller at a position facing the spinning roller in order to prevent the deformation of the material that occurs in the rib forming process (see FIG. 16 of Patent Document 3). ). When the backup roller is used, the pressure exerted on the material by the spinning roller can be received by the backup roller, and the deformation of the material can be prevented. However, the effect of preventing deflection deformation by the backup roller is not always sufficient, and particularly when the material is thin, the material is shaken during molding, and it is difficult to form a rib with high dimensional accuracy.

  Furthermore, Patent Document 3 discloses a method of reducing the diameter of both ends of a thin metal core material before forming a rib. In the case of this method, ribs cannot be formed in the reduced diameter journal portion, and the thin core metal material located in the vicinity of the journal portion has a mechanical strength different from that of the original thin core metal material by the diameter reduction processing. For this reason, in order to form a rib in a portion close to both ends of the thin metal core material, there is a problem that conditions different from those in the case of forming a rib in another portion must be selected.

JP 2000-029342 A JP 2001-305897 A JP 2002-126824 A

  The problem to be solved by the present invention is to solve the above-described problems of the prior art and to provide a method for efficiently forming reinforcing ribs having good dimensional stability on the inner surface of a thin metal core.

  According to the present invention, as a first invention, a hollow cylindrical thin metal core material is rolled in the presence of a core, thereby forming a concave groove on the outer surface and corresponding to the concave groove. After forming the ribs on the inner surface, the core is removed, and then the outer surface of the ribbed thin metal core material is processed into a flat surface. A movable rotating roller having a group of ridges composed of a plurality of ridges, and a fixed rotating roller fixedly provided at a position facing the movable rotating roller, and the protruding group of movable rotating rollers. A core having at least one concave groove group composed of a plurality of concave grooves provided in a corresponding arrangement, and a thin metal core material that is rotatable independently of the core, are formed on the convex of the movable rotary roller. Arranged so that the groove group and the groove group of the core face each other, a pair of rotation A rib group is formed on the inner surface of the thin core metal material by pressing the convex group of movable rotating rollers against the surface of the thin core metal material while rotating the roller in the same direction. When the core has a plurality of groove groups, the same operation is repeated for each groove group, so that a plurality of rib groups corresponding to the plurality of groove groups of the core A method for producing a thin-walled metal core with ribs that is formed on the inner surface of a material is provided.

  Further, as a second invention, after rolling the thin core metal material, the core is removed from the thin core metal material, and journals are formed on both ends of the thin core metal material with ribs. A method of manufacturing a thin-walled metal core with ribs that processes an outer surface into a flat surface is provided.

According to the present invention, the movable rotating roller has a protruding stripe group consisting of a plurality of protruding stripes, and the arrangement of the concave groove group consisting of a plurality of concave grooves formed in the core is movable rotation. Since it corresponds to the convex group of rollers, a plurality of ribs can be formed with good dimensional stability by a single rolling operation. Moreover, a desired number of ribs can be formed at a desired location by moving the thin metal core containing the core in the axial direction and repeating the same rolling process operation. Furthermore, since the thin cored bar is rotatably fitted into the core, it can prevent the thin cored bar from swinging, contributing to the improvement of the dimensional accuracy of the ribs, and can be realized with the prior art. It was also possible to manufacture a thin roller with ribs having a thickness of about 0.2 mm, which was difficult. Further, according to the present invention, ribs can be formed on both ends of the thin metal core material in the same manner as other parts. Furthermore, when making a thin cored bar having a journal part, the rib is formed before the journal part is formed, and therefore the rib can also be formed at that part.

FIG. 3 is a partial cross-sectional view schematically showing a configuration when the thin-walled metal core with ribs according to the first embodiment of the present invention is used as a roller metal core of a fixing roller provided in an electrophotographic image forming apparatus. It is a partial cross section figure which shows typically the 2nd embodiment of the thin metal core with a rib. It is the front view, side view, and partial enlarged view which show typically the structure of the core which provided the concave groove used in order to manufacture the thin-walled metal core with a rib shown in FIG. It is the front view and side view for demonstrating the structure of the movable rotation roller used in order to manufacture the thin metal core structure shown in FIG. It is the front view and side view for demonstrating the structure of the fixed rotation roller used in order to manufacture the thin metal core structure shown in FIG. It is a side view for demonstrating the outline | summary about the rolling processing apparatus for manufacturing the thin core metal material with a rib. It is a perspective view for demonstrating operation which manufactures the thin metal core material with a rib using a rolling processing apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 includes a rotating shaft of a roller core used as a fixing roller provided in an electrophotographic image forming apparatus such as a copying machine, a facsimile, or a printer as an example of a thin cored bar according to the first embodiment of the present invention. It is a partial sectional view showing a section typically.

  As shown in FIG. 1, the roller cored bar 10 includes a main body portion 12 wider than the sheet passing region L, and journal portions 17 and 18 having a smaller diameter than the main body portion 12 integrally formed at both ends thereof. . The material of the roller core 10 is not particularly limited, and examples thereof include aluminum (including an aluminum alloy) and iron. Of these, aluminum is preferably used because it is lightweight and has excellent temperature characteristics. Specific examples of aluminum include STH032 and STH034 (both manufactured by Toyo Aluminum Co., Ltd.).

  The main body 12 is formed flat over the entire region, but may be formed into a drum shape, that is, a shape in which the outer diameter slightly increases from the central portion toward both ends, if desired. In the case of the drum shape, the drum amount of the main body 12 can be appropriately set depending on the product performance, and is set to about 0.08 mm, for example. The drum volume is a difference D2-D1 between the outer diameter D2 outside the paper passing area L and the outer diameter D1 at the center.

  The main body 12 has a space in which a heat generating device can be inserted, and has a circular cross section. Furthermore, a rib group for increasing the rigidity is formed on the inner peripheral surface 12b of the main body portion 12. The rib group includes a central rib group 15 provided in a central region in the axial direction, and peripheral rib groups 16 and 17 respectively disposed on both outer sides in the axial direction of the central rib group 15.

  The central rib group 15 includes a central rib 15a positioned at the axial center and end ribs 15b and 15c positioned at both axial ends of the central rib group 15, respectively. The central rib 15a and a pair of left and right end ribs 15b and 15c are arranged at equal intervals. The peripheral rib groups 16 and 17 have the same shape as the central rib group 15, and are each in the vicinity of both ends of the core metal material (not including the journal portion), for example, at a position of about 20 mm from the end portion. It is provided on the inner peripheral surface 12a so that the rib at the end comes to the end.

  The shape of the rib is not particularly limited, and may be a cross-sectional shape such as an arc shape (including a semicircular shape), a U shape, or a trapezoidal shape. Preferably, it has an arc shape. In this embodiment, each of the central rib group and the rib groups at both ends has three ribs, a total of nine ribs. The shape, total number, and arrangement of the ribs can be appropriately determined in consideration of the mechanical strength necessary for the product. Usually, the total number of ribs is 3 to 30, preferably 6 to 20. In general, the rib has a height of 0.2 to 1 mm and a width of 0.5 to 3 mm, preferably a height of 0.3 to 0.7 mm and a width of 0.7 to 2 mm.

  Thus, by forming a rib on the inner peripheral surface of the roller metal core and increasing the rigidity, the roller metal core can be thinned. In particular, if a rib is provided at the central portion in the axial direction of a roller core that is easily deformed when pressure is applied from a pressure roller or the like, high strength can be obtained with a small number of ribs. In this embodiment, the thickness of the flat surface of the roller metal core after cutting the outer surface of the thin metal core material can be adjusted in a wide range, but is usually 5 mm or less, preferably 1 mm or less, more preferably 0.5 mm or less. Even if the lower limit is reduced to 0.2 mm, it can be put to practical use as a fixing roller.

  In an image forming apparatus such as an electrophotographic copying machine, generally, a toner image visualized on a developing roller is formed from an electrostatic latent image formed on the surface of a photosensitive drum, and then a recording sheet is formed on a recording sheet by a transfer roller. After the transfer, the toner image is fixed by a fixing roller. At this time, if a fixing roller having a thin roller metal core is used as the fixing roller, the temperature increase rate of the fixing roller can be improved, the rise time can be greatly shortened, and power saving can be achieved. Can do. That is, both the warm-up time and the lighting time of the halogen heater can be shortened.

  Moreover, since the mechanical strength of the roller core increases as the rib density increases, the diameter of the roller core can be reduced. As a result, the volume inside the roller metal core is reduced and the heat capacity can be reduced, so that the temperature rise by the heat source can be increased and power saving can be achieved.

  Further, when the main body portion 12 of the roller metal core 10 is formed into a drum shape, a circumferential difference can be provided in the axial direction of the fixing roller, thereby providing a difference in a feed amount (linear speed) at the time of fixing by rotation. it can. By providing a difference in the feed amount in this way, it is possible to apply tension toward both width directions of the transfer paper, thereby preventing twisting and wrinkling of the transfer paper.

  FIG. 2 is a partial cross-sectional view schematically showing a roller core 20 of a fixing roller according to the second embodiment of the present invention. The roller cored bar is different from the roller cored bar 10 of FIG. 1 in that journal portions 27 and 28 provided at both ends of the roller cored bar 20 have the same diameter as the main body 22 and ribs are the main body. 22 is formed substantially uniformly over the entire length of the inner peripheral surface 22a. In the method described in Patent Document 3, since the ribs are formed one by one, it is troublesome to form a large number of ribs and requires a long processing operation. Since the ribs can be efficiently formed by a single rolling process, a large number of ribs can be easily formed by repeating the operation. For example, the rib group 25 composed of the ribs 25a, 25b, and 25c is formed by a single rolling process, and then the rib group 26 composed of the ribs 26a, 26b, and 26c is formed, so that a total of five rolling operations are performed. By repeating the processing, 15 ribs can be formed.

  The embodiment shown in FIG. 1 is a form having three rib groups, and the embodiment shown in FIG. 2 is a form in which ribs are formed at equal intervals over the entire length of the roller core metal. Depending on the specifications such as the thickness, diameter, and material of the roller core bar, the ribs can be arranged in an appropriate form. For example, a mode in which a rib group is arranged only in the central portion, a mode in which a rib group is arranged only in both end portions, a mode in which four or more rib groups are arranged, a mode in which rib groups are arranged in a journal portion, etc. it can.

  FIG. 3 is a front view schematically showing an example of the core used in the present invention. The core 30 is formed by forming a plurality of concave grooves on a round bar-shaped shaft portion 31. In the example of FIG. 3, the core 30 includes a central concave groove group 32 and concave groove groups 33 and 34 at both ends. . Each groove group has three grooves (32a, 32b, 32c in the case of the groove group 32) arranged at equal intervals, and the same applies to the groove groups 33, 34 at both ends. is there. The number of grooves in each groove group is the same as the number of protrusions of the movable rotating roller described later, and the grooves are arranged so that each protrusion is approximately at the center of the corresponding groove. Designed to. The width of each concave groove is wider (for example, about 2 to 8 times) than the width of the ridges, and the depth is preferably about 0.5 to 3 times the height of the ridges. . The material of the core may be any material that is stronger than the thin-walled core material, but is usually made of iron.

  The thin metal core material is fitted from the end 36 of the shaft portion 31 of the core. The diameter D of the shaft portion 31 is appropriately set in consideration of the relationship between the inner diameter of the thin core metal material to be fitted and the height of the rib to be formed, but at most Dmax = [(the inner diameter of the thin core metal material) − ( If the height of the rib is not set to 2)], the core cannot be extracted from the thin metal core material after the rib is formed. On the other hand, if the diameter D of the shaft portion 31 is excessively small, it is difficult to obtain a plurality of ribs with good dimensional stability while preventing the thin core metal material from swinging. Therefore, the range of the diameter D is 0 of the maximum value Dmax. It is preferable to design at a ratio of 0.8 to 1.0, more preferably 0.9 to 1.0. It is preferable to provide a stopper portion 35 at the tip of the shaft portion 31, thereby preventing the thin core metal material fitted in the core from moving in the tip direction of the core. The stopper portion 35 can be formed by making the diameter of the tip of the shaft portion 31 larger than the inner diameter of the thin metal core material. However, the stopper portion 35 is not necessarily limited to such a mode, and has an appropriate form such as providing a protrusion at the tip. be able to.

  FIG. 4 is a front view 4 a, a side view 4 b, and an enlarged view 4 c showing a cross-sectional shape of the ridges, showing an example of a movable rotating roller having a ridge group composed of a plurality of ridges used in the present invention. The enlarged view 4c shows a portion A of the front view 4a. Reference numeral 44 in the side view 4b denotes a rotating shaft. The movable rotating roller 40 shown in this example has three ridges (42a, 42b, 42c) having an arc-shaped cross section having a height of 0.4 mm and a width of 1 mm at the center of the surface of the rotating roller 41 having a diameter of 150 mm and a width of 60 mm. ) Are provided with ridge groups 42 arranged at equal intervals, and the arrangement of the ridges corresponds to the arrangement of the groove in each groove group (32, 33, 34) of the core 30 shown in FIG. It has become. In this example, the cross-sectional shape of the ridge is an arc as shown in 46 of the enlarged view 4c, but if it is a shape effective for rib formation on the inner surface of the thin metal core material in cooperation with the concave groove of the core, An appropriate shape such as a trapezoidal shape or a polygonal shape can also be used. The material of the movable rotating roller may be any material that is stronger than the thin core metal material, but an iron roller is usually used.

  FIG. 5 is a front view 5a and a side view 5b showing an example of a fixed rotating roller used in the present invention. The rotating roller 51 is paired with the rotating roller 41 of the movable rotating roller, and has the same structure as the rotating roller 41 except that the rotating roller 51 is not provided. The material of the fixed rotating roller can be the same as that of the movable rotating roller.

  FIG. 6 is a side view for schematically explaining an outline of an example of a rolling apparatus for forming a rib on the inner surface of a thin metal core material, and FIG. 7 is a rolling process using the apparatus. It is a perspective view for demonstrating the state to do. The rolling device 61 includes a movable rotating roller 41, a fixed rotating roller 51, and a holder 64 that holds a material to be processed. The movable rotating roller 41 is the roller shown in FIG. 4, and the fixed rotating roller 51 is the roller shown in FIG. The thin metal core material 62 having the core 31 inserted therein is set on a holder 64 between the two rollers 41 and 51. The two rotating rollers are designed to rotate in the same direction (for example, the direction shown by arrow A in FIG. 6), and the movable rotating roller 41 is a fixed rotating roller as shown by arrow B in FIG. Designed to move in 51 directions. The movable rotating roller 41 gradually moves in the direction of the thin cored bar material 62 while rotating, and accordingly, the ridges 42 of the movable rotating roller 41 press the outer surface of the thinned cored bar material 62, A groove group having a shape corresponding to the ridge group 42 is formed on the outer surface of the thin core metal material 62, and at the same time, a rib group having a shape obtained by transferring the ridge group 42 to the inner surface of the thin core metal material 62 is formed.

  Further, the core 31 can be rotatably installed, but it is not always necessary to rotate the core 31. It is only necessary to set the core 31 together with the thin metal core material 62 on the holder 64. Since the thin metal core material 62 has an inner diameter larger than that of the core 31, the thin core metal material 62 can rotate independently of the core 31 without rotating, and the movable rotating roller 41 and the fixed rotating roller 51. Due to the pressing force generated by, the pair of rotating rollers rotate in the opposite direction.

  FIG. 7 schematically shows a state in which the groove group 72 (indicated by a broken line) is formed on the surface of the thin metal core material 62. The thin metal core material 62 is fitted to the position of the stopper portion 35 so as to wrap the core 31 provided with the stopper portion 35 at the tip. When the movable rotating roller 41 having the ridge group 42 (42a, 42b, 42c) and the fixed rotating roller 51 are rotated in the direction of the arrow A, the thin metal core material 62 is rotated in the direction of the arrow B, and is movable. A concave groove is formed on the outer surface of the thin metal core material 62 by the pressing force of the rotating roller 41. In this figure, it is shown that three concave grooves (indicated by broken lines) are formed on the surface of the thin metal core material by such a single rolling process operation. Although not shown, three ribs are formed on the inner surface of the thin metal core material at positions corresponding to the concave grooves. When the core 31 includes a plurality of concave groove groups, the thin core metal material 62 and the core 31 are arranged so that the position of each concave groove group matches the position of the convex stripe group of the movable rotating roller 41. A plurality of rib groups can be formed on the inner surface of the thin metal core material 62 corresponding to the plurality of concave groove groups of the core 31 by moving the position and performing the same rolling process operation as above. .

  In the present invention, the thin metal core having the ribs as described above is manufactured as follows. First, in the rib forming step (I), a movable rotating roller having a group of ridges composed of a plurality of ridges for forming a rib and movable in one direction perpendicular to the rotation axis is used as a pressing member. Between the movable rotating roller used and the fixed rotating roller fixedly provided at a position facing the movable rotating roller, at least one groove group corresponding to the protruding strip group of the movable rotating roller is provided. A hollow cylindrical thin cored bar material containing a core is sandwiched, and the movable rotating roller and the fixed rotating roller are rotated in the same direction, so that the ridge of the movable rotating roller is formed on the surface of the thin cored bar material. By pressing the group, a rib having a shape obtained by transferring the ridge group to the inner surface of the thin core metal material and at a position corresponding to at least a part of the groove group of the core is formed. By this operation, one rib group in a form in which the convex strip group of the movable rotating roller is transferred is formed. When the core has a plurality of groove groups, ribs are formed at all positions corresponding to the groove groups of the core by repeating this operation as necessary. For example, in the case where the ridge group of the movable rotating roller is composed of three ridges and the core has three groove groups each composed of three groove grooves, the pressing operation is repeated three times to obtain the total Nine ribs can be formed on the inner surface of the thin metal core material.

  This processing method is a so-called “rolling rolling” (In Feed rolling), which is a workpiece (object to be processed) between a pair of rotating rollers. The material is equivalent to the workpiece), the two rotating rollers are rotated in the same direction, and the distance between the rolls is gradually reduced to increase the pressing force against the workpiece by the roll, and the desired pressure is applied to the workpiece. It is the method of providing the shape of. In the present invention, of the pair of rotating rollers, one movable rotating roller is provided with a plurality of convex stripe groups for forming ribs, and the position of the rotating shaft is perpendicular to the longitudinal direction of the workpiece. It can be moved. The other fixed rotating roller has the same shape as that of the movable rotating roller except that it does not have a protruding stripe group, and the position of the rotating shaft of this fixed rotating roller is fixed.

  In the present invention, when rolling a workpiece, that is, a thin cored bar material, it is not used alone, but a concave groove group corresponding to the convex stripe group of the movable rotating roller is provided therein. The prepared core is arranged. At least a part of the concave groove of the core is provided so as to coincide with the arrangement of the ridges of the movable rotating roller, and the total number of the concave grooves is a multiple of the number of ridges of the movable rotating roller. Preferably there is. As above-mentioned, the number is 3-30 normally, Preferably it is 6-20. When the total number of grooves is not a multiple of the number of ridges of the movable rotating roller, a complicated operation such as using another movable rotating roller having the number of ridges corresponding to the number of extra grooves is required. This is necessary and reduces the effects of the present invention.

  The diameter of the core is set so as to ensure a space that allows the core to be pulled out from the thin core metal material after the rib is formed on the inner surface of the thin core metal material. Therefore, a gap equal to or greater than the height of the rib to be formed is generated between the thin metal core material and the core, and as a result, the thin metal core material can be rotated regardless of the movement of the core. Since the thin metal core material is sandwiched between the movable rotating roller and the fixed rotating roller, when they rotate in the same direction, they rotate in the opposite direction with the rotation. As described above, the diameter of the core is at most Dmax = [(the inner diameter of the thin metal core) − (the height of the rib × 2)], preferably 0.8 to 1.0 times Dmax, Preferably it is 0.9 to 1.0 times. As the core diameter decreases, the effect of preventing the thin cored bar material from swinging in the rolling process is reduced.

  The shape of the ridges provided on the movable rotating roller may be appropriately selected in consideration of the desired rib shape, but usually the height is 0.2 to 1 mm and the width is 0.5 to 3 mm. is there. Preferably, the height is 0.3 to 0.6 mm and the width is 0.7 to 2 mm. The number of ridges is preferably 3-6.

  When the pair of rotating rollers are rotated in the same direction, the thin core metal material is also rotated with the movement, and the ridges of the movable rotating roller are moved to the outer surface of the thin core metal material by the movement of the rotating shaft of the movable rotating roller. The desired rib is formed on the inner surface of the thin metal core material. In the present invention, since a core having a groove group arranged in a shape corresponding to the ridge group exists in the material, the pressing force when performing the rolling process is increased, or the processing speed is increased. Even if the speed is increased, the shake of the thin metal core material can be suppressed, and a rib having good dimensional stability can be formed quickly and efficiently. For example, the processing time for forming three ribs can be shortened to about 15 seconds. Generally, the number of concave grooves in the core is designed to be a multiple of the number of ridges on the movable rotating roller, so multiple rolling operations with the movable rotating roller can be performed by changing the position of the thin metal core material. By repeating the process a desired number of ribs can be formed.

  The hollow cylindrical thin metal core material to be used is appropriately selected in consideration of the shape of a desired object. Usually, the diameter is 5 to 60 mm, the length is 10 to 400 cm, and the wall thickness is 0.4. The diameter is 10 to 30 mm, the length is 15 to 50 cm, and the wall thickness is 0.4 to 1 mm.

  After the formation of the ribs is finished, an operation for removing the core from the thin metal core material is then performed. The thin metal core material has ribs on the inner surface, but the outer diameter of the core is designed so that the core can be extracted after forming the rib on the thin metal core material. The core can be extracted.

  The ribbed thin metal core material obtained at this stage has a concave groove formed on the outer surface by rolling. Therefore, a flat surface is formed by cutting the outer surface of the thin metal core material to at least the level of the bottom of the groove. This flattening process can be performed according to a conventional method, for example, by cutting as follows. The outer surface of the body portion of the thin metal core material is first roughly cut with a double cutting tool for rough cutting (rough cutting diamond tool), and then finish-cut with a finishing tool (diamond cutting tool). The rough cutting process may be performed in a plurality of stages, for example, two stages. In the case where a reduced diameter journal part is provided, the journal part can be similarly cut.

  When the ribbed thin cored bar of the present invention is used as the cored bar of the fixing roller, a journal part for attaching to the image forming apparatus is required. When it is desired to reduce the diameter of the journal part, the core part is removed from the thin metal core material, and then the journal part is formed by reducing the diameter of both ends of the thin metal core material. Conventionally, swaging processing and spinning processing are known as methods for diameter reduction processing (see, for example, Patent Document 3). In swaging, the end of the straight pipe is reduced in diameter by pushing it into a die (die). In the spinning process, the diameter is reduced by abutting the roller while chucking and rotating the body portion. According to this method, it is easy to obtain the required concentricity, and since no cleaning oil is used, there is an advantage that a cleaning process is unnecessary and it is good for environmental measures. In the present invention, the diameter can be reduced according to these known methods. The reduced diameter journal portion can be cut in the same manner in the case of the outer surface of the body portion of the thin metal core material. Moreover, when the diameter reduction of the journal part is unnecessary, this diameter reduction processing can be omitted.

  The journal part is so-called oval cut, in which the length is adjusted using an end face machining tool as necessary, and then a pair of opposed arcuate parts are removed in parallel with the central axis at the end part. Further, instead of this oval cut, so-called D cut that removes only one side, or so-called U cut that cuts into a U shape may be performed. These oval cuts, D cuts, and U-shaped cutouts are formed to prevent the drive gear from rotating.

  In the fixing roller, a surface layer may be formed by coating a release layer made of a fluororesin layer on the outer peripheral surface of the roller metal core. This surface layer is formed to a film thickness of 10 to 30 μm, for example.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, it can deform | transform and implement variously.

  Use a thin cylindrical tube made of AL alloy material (trade name STH034, Toyo Aluminum Co., Ltd.) of φ25mm × L350mm × t0.7mm as a thin core metal material, and use a rolling device to Form. First, the thin metal core material is fitted to the tip of the core and placed on a holder provided between the movable rotating roller and the fixed rotating roller. The core is φ22.8 mm × L360 mm and has a stopper portion of φ24.8 mm × width 2 mm at the tip. The core has three concave grooves having a width of 5 mm and a depth of 1 mm at the central portion at intervals of 10 mm (central concave groove group), and the outermost concave groove is located at a position of 30 mm from the front end and 40 mm from the rear end. Thus, a front end groove group and a rear end groove group (both having the same shape and the same arrangement as the central groove group) are provided. The total number of grooves in the core is nine. The movable rotating roller is an iron roller having a diameter of 150 mm × L 60 mm and three arc-shaped protrusions having a height of 0.4 mm and a width of 1 mm provided at the center of the surface at intervals of 10 mm. It is the same as the movable rotating roller except that it does not have.

  First, a thin cored bar material containing the core is placed so that the concave groove group at the tip of the core corresponds to the convex group of the movable rotating roll, and the movable rotating roller and the fixed rotating roller rotate clockwise. The movable rotary roller is gradually moved in the direction of the opposed fixed rotary roller by hydraulic pressure. By performing this rolling process at room temperature for about 15 seconds, the ridges provided on the movable rotating roller are transferred to the thin metal core material, the outer surface is formed with a concave groove, and the inner surface is formed with a rib. Thus, three ribs at the tip are formed by a single rolling process.

  Next, the thin cored bar material containing the core is arranged so that the central groove group of the core corresponds to the convex stripe group of the movable rotating roller, and the same rolling process is performed, so that the central part The three ribs are formed. Furthermore, by arranging the thin metal core material containing the core so that the rear end concave groove group of the core corresponds to the convex stripe group of the movable rotating roll and performing the same rolling process, Three ribs at the end are formed

  After forming the ribs, the thin metal core material is removed from the core. At this stage, arc-shaped ribs having a height of 0.35 to 0.4 mm and a width of about 1 mm are formed on the inner surface of the thin metal core material, and a depth of 0.35 to 0.4 mm and a width of about 1 mm are formed on the outer surface. Nine grooves are formed. The ribs have almost the same shape and are excellent in dimensional stability. The arrangement of the nine ribs corresponds to the arrangement of the concave grooves of the core, and the centers in the width direction of the ribs and the concave grooves substantially coincide.

Next, the diameter of both ends of the thin-walled metal core with ribs is reduced by spinning to form a journal portion of φ12 mm × L20 mm. Using a cutting tool, the outer diameter is cut at a spindle speed of 4500 rpm and a feed rate of 0.1 mm / rev. As a result, a flat surface having a surface roughness Rz of about 3 to 4 μm is obtained. The wall thickness after cutting is 0.25 mm. Thus, an extremely thin core metal having nine main ribs having a dimensional stability and having nine ribs having reduced diameter journals at both ends can be obtained.

According to the present invention, it is possible to efficiently manufacture a thin metal core with a reinforcing rib suitable for a core metal for a fixing roller of an electrophotographic copying machine, a laser printer, a facsimile machine or the like. Further, according to the present invention, ribs can be formed in any portion of the thin cored bar and further in the journal portion which is reduced in diameter. It is also possible to manufacture an ultrathin core metal having a thickness of about 2 mm.

10 Roller core (core metal structure)
12 Main body 12a Inner peripheral surface 15 Central rib group 16, 17 Peripheral rib group 18, 19 Journal part 30 Core 31 Core shaft part 32 Central concave groove group 33, 34 Peripheral concave groove group 40 Movable rotating roller 42 Convex Strip group 50 Fixed rotating roller 62 Thin cored bar material 64 Holder 72 Groove group

Claims (10)

By rolling a hollow cylindrical thin metal core material in the presence of the core, a concave groove is formed on the outer surface and a rib is formed on the inner surface corresponding to the concave groove, and then the core is removed. Then, it is a method for manufacturing a thin-walled metal core with ribs, which processes the outer surface of the thin-walled metal core material with ribs into a flat surface,
The rolling process is performed by using a movable rotating roller having a ridge group composed of a plurality of ridges for forming a rib, and a fixed rotating roller fixedly provided at a position facing the movable rotating roller.
A core provided with at least one concave groove group composed of a plurality of concave grooves provided in an arrangement corresponding to the convex stripe group of the movable rotating roller, and a thin wall that is rotatable independently of the core. The metal core material is arranged so that the convex strip group of the movable rotating roller and the concave groove group of the core face each other,
A rib group in which the ridge group is transferred to the inner surface of the thin core metal material by pressing the ridge group of the movable rotary roller against the surface of the thin core metal material while rotating a pair of rotary rollers in the same direction. When the core has a plurality of groove groups, a plurality of rib groups corresponding to the plurality of groove groups of the core are thinned by repeating the same operation for each groove group. A method for producing a thin-walled metal core with ribs, which is formed on the inner surface of a metal core material.   2. The method for producing a thin-walled metal core with ribs according to claim 1, further comprising a step of forming journals at both ends of the thin-wall metal material with ribs after the removal of the core.   The manufacturing method of the thin metal core with a rib of Claim 1 or 2 whose number of the protruding item | line of a movable rotating roller is 3-6.   The method for producing a thin cored bar with ribs according to any one of claims 1 to 3, wherein the ridges of the movable rotating roller have a height of 0.2 to 1 mm and a width of 0.5 to 3 mm.   The manufacturing method of the thin metal core with a rib in any one of Claims 1-4 whose number of the concave groove | channel of a core is a multiple of the number of the protruding item | line of a movable rotary roller.   The groove of the core has a depth of 0.5 to 3 times the height of the ridge and a width of 2 to 8 times the width of the ridge. Manufacturing method of thin cored bar with ribs.   The manufacturing method of the thin metal core with a rib in any one of Claims 1-6 in which a core has a stopper part in the front-end | tip.   The thickness of the main-body part of a thin-wall metal core with a rib is 0.2-1 mm, The manufacturing method of the thin-wall metal core with a rib in any one of Claims 1-7.   The manufacturing method of the thin metal core with a rib in any one of Claims 1-8 whose rib of a thin metal core with a rib is 0.2-1 mm in height and 0.5-3 mm in width.   The ribbed thin wall according to any one of claims 1 to 9, wherein the core has a diameter of 0.8 to 1.0 times [(inner diameter of thin core metal material)-(rib height x 2)]. A method for manufacturing a cored bar.

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