Method for manufacturing a tape cartridge, a tape reel, and a reel hub

Abstract

[Problem] To provide a method for manufacturing: a tape cartridge provided with a reel hub; a tape reel; and a reel hub. The method can ensure desired molding quality in single molding. [Solution] This tape cartridge according to one embodiment is equipped with a first flange, a second flange, and a reel hub around which tape is wound. The reel hub is disposed between the first flange and the second flange. The reel hub includes a cylindrical metal ring and a molded body made of a synthetic resin. The molded body includes a first resin section formed on the inner circumferential surface of the metal ring, and a second resin section formed on the outer circumferential surface of the metal ring. The first resin section includes a plurality of first recesses that are formed at intervals in the circumferential direction of the metal ring.

Description

Technical Field

[0001] The present technology relates to a tape cartridge including a reel hub with an insert-molded metal ring, a tape reel, and a method for manufacturing the reel hub.

Background Art

[0002] As a magnetic tape cartridge used as an external recording medium such as a computer, there is known a type in which a single tape reel around which a magnetic tape is wound is rotatably accommodated in a cartridge case. The tape reel has a reel hub around which the magnetic tape is wound, and an upper flange and a lower flange respectively disposed at both ends of the reel hub.

[0003] With the recent increase in the recording capacity of tape cartridges, the thickness of the magnetic tape has been reduced and the tape length has been increased. On the other hand, since the amount of deformation of the reel hub due to the winding tension (winding pressure) of the magnetic tape increases, for example, the width of the tape region located on the inner peripheral side of the tape reel close to the reel hub may expand, which may adversely affect the recording and playback characteristics of the magnetic tape.

[0004] On the other hand, a tape reel including a reel hub with an insert-molded cylindrical metal ring is known. A reel hub having such a configuration can suppress deformation of the reel hub due to the winding pressure of the magnetic tape because the rigidity of the hub surface is increased. As a method for manufacturing a reel hub with an insert-molded metal ring, for example, Patent Document 1 discloses a method in which, with a metal ring inserted in a mold, a primary molding portion that covers the inner peripheral surface of the metal ring is molded by primary molding, and then a secondary molding portion that covers the outer peripheral surface of the metal ring is molded by secondary molding.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the manufacturing method described in Patent Document 1, since the molding process requires two processes of primary molding and secondary molding, a mold for primary molding and a mold for secondary molding are required, and there is a problem that reduction of manufacturing cost and improvement of productivity cannot be achieved. Further, when attempting to simultaneously mold a resin portion covering the inner peripheral surface of the metal ring and a resin portion covering the outer peripheral surface of the metal ring in a single molding, when resin is injected around the metal ring disposed in the mold, the position of the metal ring fluctuates due to the injection pressure of the resin, and it is difficult to accurately mold resin portions of a desired thickness on the inner and outer circumferences of the metal ring.

[0007] In view of the above circumstances, an object of the present technology is to provide a tape cartridge including a reel hub capable of ensuring a desired molding quality in a single molding, a tape reel, and a method for manufacturing a reel hub.

Means for Solving the Problems

[0008] A tape cartridge according to one embodiment of the present technology includes a first flange, a second flange, and a reel hub around which a tape is wound. The reel hub is disposed between the first flange and the second flange. The reel hub has a cylindrical metal ring and a molded body made of synthetic resin. The molded body has a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring. The first resin portion has a plurality of first recesses formed at intervals in the circumferential direction of the metal ring.

[0009] The plurality of first recesses may be groove portions extending in the axial direction of the metal ring.

[0010] The plurality of first recesses may be formed from one axial end of the first resin portion to the vicinity of the other axial end of the first resin portion.

[0011] The molded body may further include a third resin portion formed on a surface on one axial end side of the metal ring. The third resin portion has a plurality of holes formed at intervals in the circumferential direction of the metal ring.

[0012] The first flange may have a plurality of protrusions protruding toward one axial end of the first resin portion. The first resin portion further has a plurality of second recesses that engage with the plurality of protrusions.

[0013] The plurality of second recesses may be a groove portion common to the plurality of first recesses.

[0014] The first flange has a plurality of first engaging portions provided on the inner diameter side of the reel hub, and the second flange may have a plurality of second engaging portions provided on the inner diameter side of the reel hub and engaging with the plurality of first engaging portions. The reel hub is disposed between the first flange and the second flange that are mutually coupled via the plurality of first engaging portions and the plurality of second engaging portions.

[0015] A tape reel according to one embodiment of the present technology includes a first flange, a second flange, and a reel hub disposed between the first flange and the second flange. The reel hub has a cylindrical metal ring and a molded body made of synthetic resin. The molded body has a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring. The first resin portion has a plurality of first recesses formed at intervals in the circumferential direction of the metal ring.

[0016] The manufacturing method of a reel hub according to one aspect of the present technology includes a cylindrical portion facing the inner peripheral surface of a metal ring, a first base portion integrally formed with the cylindrical portion and facing one axial end of the metal ring, and a plurality of protruding portions extending along the axial direction and protruding from the outer peripheral surface of the cylindrical portion toward the inner peripheral surface of the metal ring. The metal ring is disposed in a first mold having these components. A second mold having a cylindrical portion facing the outer peripheral surface of the metal ring and a second base portion integrally formed with the cylindrical portion and facing the other axial end of the metal ring is combined with the first mold. A synthetic resin material is injected between the outer peripheral portion of the cylindrical portion and the inner peripheral surface of the cylindrical portion through an injection port formed between the cylindrical portion and the second base portion.

[0017] The injection port may be formed over the entire circumference of the other end of the metal ring.

[0018] The first base portion may have a plurality of protruding portions that support the surface on the one end side of the metal ring.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments according to the present technology will be described with reference to the drawings.

[0021] Figures 1A and 1B are overall perspective views of a tape cartridge 1 according to an embodiment of the present technology. Figure 1A is a perspective view when viewed from the upper surface (upper shell 2) side, and Figure 1B is a perspective view when viewed from the lower surface (lower shell 3) side. Figure 2 is an exploded perspective view of the tape cartridge 1, and Figure 3 is a side cross-sectional view of the tape reel 5.

[0022] [Overall Configuration] The tape cartridge 1 of the present embodiment is configured as a magnetic tape cartridge conforming to the LTO (Linear Tape Open) standard. The tape cartridge 1 has a configuration in which a single tape reel 5 around which a magnetic tape 22 is wound is rotatably housed inside a cartridge case 4 formed by coupling an upper shell 2 and a lower shell 3 with a plurality of screw members 43.

[0023] The tape reel 5 has a cylindrical reel hub 6, an upper flange 7 disposed at the upper end (open end) of the reel hub 6, and a lower flange 8 disposed at the lower end of the reel hub 6. The upper flange 7 and the lower flange 8 are formed of injection molded bodies of a synthetic resin material, and the reel hub 6 is formed of an injection molded body of a synthetic resin material incorporating a metal ring by insert molding.

[0024] A chucking gear 9 that engages with a reel rotation drive shaft of a tape drive device (not shown) is formed in an annular shape at the center of the lower surface of the tape reel 5, and as shown in Figure 1B, it is exposed to the outside through an opening 10 provided at the center of the lower shell 3. An annular metal plate 11 that magnetically adsorbs to the reel rotation drive shaft is fixed to the outer surface of the bottom of the lower flange 8 by insert molding on the inner peripheral side of this chucking gear 9.

[0025] The tape cartridge 1 is provided with a reel lock mechanism for suppressing the rotation of the tape reel 5 when it is not in use. The reel lock mechanism includes a plurality of gear formation walls 86 erected on the upper surface of the lower flange 8, a reel lock member 13 having an engagement tooth 13a that meshes with a gear portion 86a formed on the upper surface of the gear formation wall 86, a reel lock release member 14 for releasing the engagement between the gear formation wall 86 and the reel lock member 13, and a reel spring 15 provided between the inner surface of the upper shell 2 and the upper surface of the reel lock member 13. The reel spring 15 is a coil spring and biases the tape reel 5 toward the lower shell 3 via the reel lock member 13.

[0026] The plurality of gear formation walls 86 have an arc shape and are formed at intervals on the same circumference around the axis of the reel hub 6. The engagement teeth 13a of the reel lock member 13 facing the gear portion 86a of the gear formation wall 86 are formed in an annular shape on the lower surface of the reel lock member 13 and are constantly biased in a direction to engage with the gear portion 86a under the action of the reel spring 15.

[0027] The reel lock release member 14 has a substantially triangular shape and is disposed between the lower flange 8 and the reel lock member 13. Three legs 14a protrude downward from near each apex of the substantially triangular shape on the lower surface of the reel lock release member 14. These legs are located between the gears of the chucking gear 9 through insertion holes 88 (see FIG. 4) formed in the lower flange 8 corresponding to each leg 14a when the cartridge is not in use.

[0028] Each leg 14a of the reel lock release member 14 is pressed upward by the reel rotation drive shaft of the tape drive device that engages with the chucking gear 9 during use of the cartridge, thereby moving the reel lock member 13 to the unlock position against the biasing force of the reel spring 15. And it is configured to be rotatable with respect to the reel lock member 13 together with the tape reel 5. A support surface 14b for supporting a sliding contact portion having a substantially arc-shaped cross section protruding from the substantially central portion of the lower surface of the reel lock member 13 is provided at the substantially central portion of the upper surface of the reel lock release member 14.

[0029] On one side wall 26 of the cartridge case 4, an outlet 27 for pulling out one end of the magnetic tape 22 to the outside is provided. Inside the side wall 26, a slide door 29 for opening and closing the outlet 27 is arranged. The slide door 29 is configured to slide in a direction to open the outlet 27 against the biasing force of the torsion spring 57 by engaging with a tape loading mechanism (not shown) of the tape drive device.

[0030] A leader pin 31 is fixed to one end of the magnetic tape 22. The leader pin 31 is configured to be detachably attached to a pin holding portion 33 provided on the inner side of the outlet 27. The pin holding portion 33 is attached to the inner surfaces of the upper shell 2 and the lower shell 3, respectively, and is configured to be able to elastically hold the upper end portion and the lower end portion of the leader pin 31.

[0031] And inside the cartridge case 4, in addition to the safety tab 25 for preventing accidental erasure of the information recorded on the magnetic tape 22, a cartridge memory 54 capable of non-contact reading and writing of the content related to the information recorded on the magnetic tape 22 is arranged. The cartridge memory 54 is composed of a non-contact communication medium on which an antenna coil, an IC chip, etc. are mounted on a substrate.

[0032] [Tape reel] Subsequently, the details of the tape reel 5 will be described. FIG. 4 is an exploded perspective view of the tape reel 5, and FIG. 5 is an overall perspective view of the tape reel.

[0033] As described above, the tape reel 5 has a reel hub 6, an upper flange 7 (second flange), and a lower flange 8 (first flange). The reel hub 6, the upper flange 7, and the lower flange 8 are separate parts, and the tape reel 5 is configured by combining them as shown in FIGS. 3 and 4.

[0034] The reel hub 6 functions as a core for winding the magnetic tape 22 and is disposed between the upper flange 7 and the lower flange 8. The reel hub 6 is a cylindrical member having an inner peripheral surface 61, an outer peripheral surface 62, a lower flange side end surface 63 facing the lower flange 8, and an upper flange side end surface 64 facing the upper flange 7. The outer diameter of the reel hub 6 is 44 mm, and its axial height is slightly larger than the width of the magnetic tape 22 (for example, 12.65 mm) (for example, 12.86 mm). As will be described in detail later, the reel hub 6 is formed of an injection molded body of a synthetic resin material incorporating a metal ring by insert molding.

[0035] The upper flange 7 has a disc shape and is typically composed of an injection molded body of a synthetic resin material such as PC or ABS, and typically, a material having translucency. The upper flange 7 has a circular opening 71 at the center, and an annular protrusion 72 is provided that hangs down from the peripheral edge of the opening 71 toward the reel hub 6. The outer diameter of the annular protrusion 72 is formed slightly smaller than the inner diameter of the reel hub 6. By fitting the annular protrusion 72 to the tapered surface 640 formed on the inner peripheral edge of the upper flange side end surface 64 of the reel hub 6, the center of the upper flange 7 is positioned on the axis of the reel hub 6, and the upper flange side end surface 64 faces the lower surface of the upper flange 7 on the outer peripheral side of the annular protrusion 72 (see FIGS. 3 and 6).

[0036] The upper flange 7 further has a plurality of first engaging portions 73 that engage with the lower flange 8. The first engaging portions 73 are provided on the radially inner side of the reel hub 6 and are tongue-shaped plate pieces that partially extend from the annular protrusion 72 toward the inside of the reel hub 6. In this embodiment, the first engaging portions 73 are provided at three locations at equal angular intervals. The number of the first engaging portions 73 is not limited to three, and may be two or four or more.

[0037] Note that the above-described opening 71, annular protrusion 72, and plurality of first engaging portions 73 are formed simultaneously when the upper flange 7 is molded.

[0038] The lower flange 8 has a disk shape and is formed of an injection molded body of a synthetic resin material such as PC or ABS. An annular chucking gear 9 is provided at the center of the lower surface of the lower flange 8, and a metal plate 11 is fixed to the inner peripheral side of the chucking gear 9.

[0039] At the center of the upper surface of the lower flange 8, an annular support portion 82 for supporting the lower flange side end surface 63 of the reel hub 6 is provided. At a predetermined position on the inner peripheral edge of this support portion 82, a plurality of protrusions 84 that engage with a plurality of engaging recesses 652 (second recesses) provided on the inner peripheral surface 61 of the reel hub 6 are provided. The protrusions 84 regulate the relative rotation of the lower flange 8 with respect to the reel hub 6 about the axis by the engaging action with the engaging recesses 652.

[0040] On the radially inner side of the diameter of the support portion 82 in the lower flange 8, a plurality of insertion holes 88 through which the leg portions 14a of the reel unlock member 14 pass, a plurality of gear forming walls 86 having gear portions 86a on the upper surface that engage with the engaging teeth 13a of the reel lock member 13, and a plurality of guide wall portions 87 for aligning the reel lock member 13 and the reel hub 6 with respect to the lower flange 8 are respectively provided. The reel lock member 13 is arranged on the inner peripheral side of each guide wall portion 87, so that the center of the reel lock member 13 is guided to the axial center position of the reel hub 6. The reel hub 6 is arranged on the outer peripheral side of each guide wall portion 87, so that it is positioned radially with respect to the lower flange 8. A tapered surface 630 for enhancing the assemblability to each guide wall portion 87 is formed on the inner peripheral edge of the lower flange side end surface 63 of the reel hub 6 (see FIG. 6). The gear forming walls 86 and the guide wall portions 87 are each a set of two, and a total of three sets are arranged at equal angular intervals on the inner peripheral side of the support portion 82.

[0041] The lower flange 8 further has a plurality of second engaging portions 83 that engage with a plurality of first engaging portions 73 of the upper flange 7. The second engaging portions 83 are provided on the radially inner side of the reel hub 6 and are plate-like claw portions that protrude from the inner peripheral side of the support portion 82 toward the first engaging portions 73. The second engaging portions 83 are arranged between the above-described set of gear forming walls 86 and are provided at three locations at equal angular intervals on the inner peripheral side of the support portion 82.

[0042] The second engaging portion 83 engages, by a snap fit method, with a rectangular engaging hole 73a provided at the tip of the first engaging portion 73 from the outer peripheral side of the first engaging portion 73 (see FIG. 3). Thereby, the upper flange 70 and the lower flange 80 are integrally joined, and the reel hub 6 is clamped between the upper flange 7 and the lower flange 8.

[0043] Note that the above-described chucking gear 9, support portion 82, plurality of second engaging portions 83, plurality of engaging protrusions 84, plurality of gear forming walls 86, plurality of guide wall portions 87, and plurality of insertion holes 88 are formed simultaneously when the lower flange 8 is molded.

[0044] [Reel hub] Subsequently, details of the reel hub 6 will be described.

[0045] FIG. 6 is a cross-sectional perspective view of the reel hub 6. FIG. 7 is an overall perspective view of the reel hub 6 as viewed from the side end face 63 side of the lower flange, and FIG. 8 is a longitudinal sectional view of the main part thereof. The reel hub 6 has a cylindrical metal ring 610 and a molded body 620 made of synthetic resin formed so as to cover the periphery of the metal ring 610.

[0046] The metal material constituting the metal ring 610 is not particularly limited, but when applied to the reel hub 6 constituting the winding core of the magnetic tape 22, the metal ring 610 is made of, for example, a non-magnetic metal material such as stainless steel (SUS304, SUS303), aluminum alloy, etc. The height of the metal ring 610 along the axial direction is, for example, about 11.8 mm, and the thickness is, for example, about 1 mm (see FIG. 8).

[0047] The synthetic resin material constituting the molded body 620 is not particularly limited. In this embodiment, it is composed of a plastic material having rigidity, heat resistance, chemical resistance, etc., such as polycarbonate (PC) and polyphenylene sulfide (PPS). Further, the synthetic resin material may be a composite plastic material containing a glass filler or the like. Thereby, the strength of the molded body 620 is improved, and the rigidity of the reel hub 6 is enhanced. The type of the filler is not particularly limited. For example, by using a plate-like (flake-like) filler, the anisotropy of the molding shrinkage rate can be reduced, and thereby the deterioration of the cylindrical accuracy due to welding or the like can be improved.

[0048] The molded body 620 is formed around the metal ring 610 so as to cover the inner peripheral surface, the outer peripheral surface, and both end surfaces in the axial direction thereof. Specifically, the molded body 620 includes a first resin portion 621 formed on the inner peripheral surface of the metal ring 610, a second resin portion 622 formed on the outer peripheral surface of the metal ring 610, a third resin portion 623 formed on the end surface on the lower flange 8 side of the metal ring 610, and a fourth resin portion 624 formed on the end surface on the upper flange 7 side of the metal ring 610.

[0049] The first resin portion 621 is formed in a cylindrical shape along the inner peripheral surface of the metal ring 610 to form the inner peripheral surface 61 of the reel hub 6. The second resin portion 622 is formed in a cylindrical shape along the outer peripheral surface of the metal ring 610 to form the outer peripheral surface 62 of the reel hub 6. The third resin portion 623 is formed on the end surface on the lower flange 8 side of the metal ring 610 to form the end surface 63 on the lower flange side of the reel hub 6. The fourth resin portion 624 is formed on the end surface on the upper flange 7 side of the metal ring 610 to form the end surface 64 on the upper flange side of the reel hub 6.

[0050] Since the molded body 620 is formed to mold the metal ring 610, each surface of the reel hub 6 can be formed with a desired accuracy as compared with the case where the reel hub 6 is composed only of the metal ring 610. In particular, since the outer peripheral surface 62 of the reel hub 6 that contacts the magnetic tape 22 is formed by the molded body 620 (the second resin portion 622), the cylindrical accuracy of the outer peripheral surface 62 of the reel hub 6 can be improved without requiring special processing on the outer peripheral surface of the metal ring 610.

[0051] The molding method of the molded body 620 is not particularly limited. In the present embodiment, as will be described later, each resin portion 621 to 624 is simultaneously formed by one molding. In order to ensure the desired molding quality, the first resin portion 621 and the second resin portion 622 are formed with the same thickness (for example, about 1.2 mm) as each other. The thicknesses of the third resin portion 623 and the fourth resin portion 624 are not particularly limited, and the thickness of the third resin portion 623 is about 0.50 mm, and the thickness of the fourth resin portion 624 is about 0.56 mm.

[0052] (First recess) The first resin portion 621 has a plurality of positioning recesses 651 (first recesses) formed at intervals in the circumferential direction of the metal ring 610 (reel hub 6). The plurality of positioning recesses 651 are recesses formed on the inner peripheral surface 61 of the reel hub 6 by a plurality of ridge portions 913 (see FIG. 9) formed on the surface of the mold facing the inner peripheral surface of the metal ring 610 when the metal ring 610 is insert-molded.

[0053] FIG. 9 is an overall perspective view showing a first mold 91 for molding the reel hub 6, FIG. 10 is a cross-sectional view taken along line A-A in FIG. 9, FIG. 11 is an overall perspective view of the first mold 91 with the metal ring 610 set therein, and FIG. 12 is a cross-sectional view corresponding to FIG. 10 for FIG. 11.

[0054] The first mold 91 is configured as a movable mold and is configured to be movable with respect to a second mold 92 (see FIG. 13) serving as a fixed mold described later. The first mold 91 has a stepped cylindrical shape having a base portion 911 (first base portion) and a core portion 912 integrally formed with the base portion 911.

[0055] The base portion 911 has an outer diameter larger than the outer diameter of the metal ring 610. The core portion 912 is formed concentrically with the base portion 911. The core portion 912 has an outer diameter smaller than the inner diameter of the metal ring 610 and is a cylindrical portion facing the inner peripheral surface of the metal ring 610. The height of the core portion 912 is formed slightly lower than the height of the metal ring 610, and when the core portion 912 is inserted into the metal ring 610, the upper surface of the core portion 912 is buried slightly below the upper end portion of the metal ring 610.

[0056] The plurality of ridge portions 913 described above are provided at predetermined positions on the outer peripheral surface of the core portion 912. The plurality of ridge portions 913 extend along the axial direction of the metal ring 610 and project from the outer peripheral surface of the core portion 912 toward the inner peripheral surface of the metal ring 610. Each ridge portion 913 is for radially positioning the metal ring 610 with respect to the core portion 912. Therefore, each ridge portion 913 is preferably provided on the peripheral surface of the core portion 912 with a protruding amount capable of contacting the inner peripheral surface of the metal ring 610. As shown in FIG. 10, the lower end portion of each ridge portion 913 is in contact with the upper surface of the base portion 911, and a tapered portion T1 for enhancing the attachability of the metal ring 610 to the core portion 912 is provided at the upper end portion thereof.

[0057] The plurality of positioning recesses 651 provided on the inner peripheral surface of the reel hub 6 are formed in a shape corresponding to each ridge portion 913 at positions corresponding to each ridge portion 913. In the present embodiment, a total of three sets (six in total) of a pair of positioning recesses 651 are provided on the inner peripheral surface of the reel hub 6 at equal angular intervals. The number of the positioning recesses 651 is not limited to this, and at least three or more are sufficient.

[0058] The positioning recess 651 is a groove extending in the axial direction of the metal ring 610. The shape of the groove is not particularly limited. In this embodiment, it is a square groove, but other shapes such as a V-shaped groove or a U-shaped groove may also be used. The inner peripheral surface of the metal ring 610 may be partially exposed from the bottom of the positioning recess 651.

[0059] Furthermore, the positioning recess 651 is formed from one axial end (the lower flange side end face 63) of the first resin portion 621 to the vicinity of the other axial end (the upper flange side end face 64) of the first resin portion 621. Since the positioning recess 651 extends to the one end of the first resin portion 621, after the reel hub 6 is molded, the reel hub 6 can be easily separated from the core portion 912.

[0060] (Second recess) The first resin portion 621 further has a plurality of engaging recesses 652 (second recesses) formed at intervals in the circumferential direction of the metal ring 610 (reel hub 6). The plurality of engaging recesses 652 engage with the plurality of engaging protrusions 84 formed on the lower flange 8 respectively, thereby positioning the reel hub 6 with respect to the lower flange 8.

[0061] The plurality of engaging recesses 652 are formed by a plurality of convex portions 914 provided on the outer peripheral surface of the core portion 912 of the first mold 91 (see FIG. 9). Each convex portion 914 extends along the axial direction of the core portion 912 from the upper surface of the base portion 911 and projects from the outer peripheral surface of the core portion 912 toward the inner peripheral surface of the metal ring 610. The protruding amount of each convex portion 914 is not particularly limited and is the same as or smaller than the protruding amount of the ridge portion 913.

[0062] The plurality of engaging recesses 652 are formed in positions corresponding to the respective convex portions 914 and in shapes corresponding to the respective convex portions 914. In the present embodiment, three engaging recesses 652 are provided at equal angular intervals between each pair of positioning recesses 651. The number of engaging recesses 652 is not limited to this, and at least three or more may be provided. The height of each engaging recess 652 (the length along the axial direction of the metal ring 610) is not particularly limited, and may be higher than the engaging protrusion 84 of the lower flange 8. In the present embodiment, it is formed from the end portion on the base portion 911 side of the core portion 912 to the vicinity of the center in the height direction of the core portion 912.

[0063] (Hole portion) The third resin portion 623 forming the lower flange side end face 63 of the reel hub 6 has a plurality of hole portions 653 as shown in FIG. 7. The plurality of hole portions 653 are formed at intervals in the circumferential direction of the metal ring 610 (reel hub 6), and in the present embodiment, are formed at equal angular intervals in the third resin portion 623.

[0064] The plurality of hole portions 653 are formed by a plurality of protruding portions 915 provided on the upper surface of the base portion 911 of the first mold 91 (see FIG. 9). Each protruding portion 915 protrudes from the upper surface of the base portion 911 along the periphery of the core portion 912 toward the lower surface of the metal ring 610 (see FIGS. 11 and 12). The plurality of protruding portions 915 support the lower surface of the metal ring 610 inserted into the core portion 912 at multiple points, thereby forming a predetermined gap between the lower surface of the metal ring 610 and the upper surface of the base portion 611. The predetermined gap corresponds to the thickness of the third resin portion 623.

[0065] The plurality of hole portions 653 are formed in positions corresponding to the respective protruding portions 915 and in shapes corresponding to the respective protruding portions 915. In the present embodiment, three hole portions 653 are provided at equal angular intervals between each pair of positioning recesses 651. The number of hole portions 653 is not limited to this, and at least three or more may be provided. The end face of the metal ring 610 may be partially exposed from the bottom of the hole portion 653.

[0066] (Method for manufacturing a reel hub) Next, a method for molding the reel hub 6 configured as described above will be described with reference to FIGS. 11 to 14. FIGS. 13 and 14 are schematic views for explaining the method for molding the reel hub 6. In the present embodiment, a molding method using a film gate system will be described as an example.

[0067] First, the metal ring 610 is inserted into the core portion 912 of the first mold 91 so that the inner peripheral surface of the metal ring 610 faces the core portion 912 of the first mold 91 (see FIGS. 11 and 12). At this time, the plurality of protrusion portions 913 formed on the outer peripheral surface of the core portion 912 concentrically arrange the metal ring 610 with respect to the core portion 912. Further, a gap for forming the first resin portion 621 is formed between the outer peripheral surface of the core portion 912 and the inner peripheral surface of the metal ring 610.

[0068] On the other hand, the lower end portion of the metal ring 610 is supported by the plurality of protrusion portions 915 formed on the upper surface of the base portion 911. Thereby, the upper surface of the base portion 911 faces the lower end portion of the metal ring 610 with a predetermined gap therebetween.

[0069] Subsequently, as shown in FIGS. 13 and 14, the first mold 91 is combined with the second mold 92. The second mold 92 has a base portion 921 (second base portion) and a cylindrical portion 922 integrally formed with the base portion 921.

[0070] The cylindrical portion 922 is concentrically combined with the core portion 912 so as to face the outer peripheral surface of the metal ring 610 with a gap for forming the second resin portion 622 therebetween. The base portion 921 has a resin injection port 923 (see FIG. 13), and between the upper end portion of the metal ring 610 and the upper surface of the core portion 912 of the first mold 91, it is formed so as to be able to form an outflow path for flowing out resin from the resin injection port 923 toward the outer peripheral surface of the core portion 912 and the inner peripheral surface of the cylindrical portion 922. As shown in FIG. 14, the first mold 91 and the second mold 92 are combined with each other by the upper surface of the base portion 911 being in close contact with the entire circumference of the lower end portion of the cylindrical portion 922. At this time, the above-mentioned outflow path forms a part of the cavity formed between the first mold 91 and the second mold 92.

[0071] Subsequently, as shown in FIG. 14, a paste-like synthetic resin material R is injected into the cavity through the resin injection port 923, thereby forming a molded body 620 that covers the periphery of the metal ring 610. The synthetic resin material R flows between the outer peripheral surface of the core portion 912 and the inner peripheral surface of the cylindrical portion 922, thereby covering the inner peripheral surface, the outer peripheral surface, and both end surfaces in the axial direction of the metal ring 610. The base portion 921 of the second mold 92 is provided with an annular ridge portion 924 that protrudes toward the upper surface peripheral edge portion of the core portion 912. The ridge portion 924 locally narrows a part of the outflow path for flowing the synthetic resin material R from the resin injection port 923 toward the outer peripheral side of the core portion 912. As a result, the resin injection port 923 is formed over the entire circumference of the upper end of the metal ring 610 (the end portion on the upper flange 7 side), and the synthetic resin material R can be uniformly injected over the entire circumference between the outer peripheral surface of the core portion 912 and the inner peripheral surface of the cylindrical portion 922.

[0072] After the injected synthetic resin material R is cooled, the first mold 91 and the second mold 92 are separated from each other, and the insert molded body of the metal ring 610 is removed from the first mold 91. FIG. 15 is an overall perspective view of the insert molded body 100, and FIG. 16 is a longitudinal sectional view thereof.

[0073] As shown in FIGS. 15 and 16, the insert molded body 100 has a structure in which the reel hub 6 and the runner portion 90 are integrated. The runner portion 90 is separated from the reel hub 6 by cutting the peripheral edge portion of its disc portion 91. In this case, a gate mark, which is a resin injection path, is formed over the entire circumference at the inner peripheral edge portion of the upper flange side end surface 64 of the reel hub 6.

[0074] [Operation of this Embodiment] As described above, according to this embodiment, in one molding step, the reel hub 6 in which the periphery of the metal ring 610 is covered with the molded body 620 can be molded. Thereby, it is possible to reduce the manufacturing cost and improve the productivity of the reel hub 6 and the tape reel 5 including the same.

[0075] Also, when manufacturing the reel hub 6, since the inner peripheral surface of the metal ring 610 is supported by a plurality of protrusions 913 formed on the outer peripheral surface of the core portion 912 of the first mold 91, the metal ring 610 can be concentrically arranged with respect to the columnar core portion 912, and high-precision positioning of the metal ring 610 with respect to the first mold 91 becomes possible. As a result, displacement of the metal ring 610 with respect to the first mold 91 due to the injection pressure of the synthetic resin material R can be prevented, and the first resin portion 621 and the second resin portion 622 that respectively cover the inner peripheral surface and the outer peripheral surface of the metal ring 610 can be uniformly formed over the entire circumference.

[0076] In particular, since the protrusions 913 are provided at equal angular intervals in the circumferential direction of the metal ring 610 in three sets with each pair as a unit, generation of sink marks in the first resin portion 621 formed on the inner peripheral surface of the reel hub 6 can be suppressed. As a result, the thickness of the first resin portion 621 in the region other than the positioning recess 651 can be made uniform.

[0077] Furthermore, in the tape reel 5 provided with the reel hub 6 configured as described above, since the reel hub 6 is formed of an insert molded body of the metal ring 610, for example, compared with the case where the lower flange and the reel hub are formed of an integrally molded body of a synthetic resin material, the rigidity of the reel hub 6 can be increased. As a result, fluctuations in the width of the magnetic tape wound around the reel hub are suppressed, and stable recording and reproduction accuracy can be ensured even in the tape region close to the reel hub.

[0078] In particular, with the recent increase in the recording capacity of tape cartridges, the thickness of the magnetic tape 22 has been reduced and the tape length has been increased. On the other hand, deformation of the reel hub inward in diameter due to winding of the magnetic tape has become a problem. For example, in the case of a synthetic resin reel hub 60 integrally formed with the lower flange 8, as shown in FIG. 17, the amount of deformation may increase as the reel hub 60 curves in a direction convex inward in diameter, as shown somewhat exaggeratedly in the figure. In this case, stress in the tape width direction also acts on the magnetic tape 22, so a change in the width dimension of the magnetic tape 22 becomes a problem. Further, when the storage environment of the tape cartridge is high temperature and high humidity, there is a possibility that the width dimension of the magnetic tape wound in the vicinity of the reel hub may partially change due to deformation of the reel hub.

[0079] FIG. 18 is a schematic diagram for explaining changes in the width dimension of the magnetic tape due to deformation of the reel hub. As shown in FIG. 18, the width dimension of the magnetic tape wound around the tape reel in which the reel hub has deformed is different in each of the BOT (Begin of Tape), MOT (Middle of Tape), and EOT (End of Tape) regions. BOT refers to the outer peripheral region near the tape tip where the leader pin is attached, EOT refers to the inner peripheral region near the reel hub, and MOT refers to the region between EOT and BOT. If the average values of the tape widths in the BOT, MOT, and EOT regions are W1, W2, and W3, respectively, the amount of variation (expansion amount) in the tape width dimension is larger on the inner peripheral side, which is more susceptible to the influence of deformation of the reel hub. Typically, the tape width sizes in each region are such that W1 < W2 < W3. And if the expansion amount of the magnetic tape becomes too large, it may adversely affect the recording and playback characteristics of the magnetic tape.

[0080] Here, as shown in FIG. 19, the magnetic tape 22 includes a tape-shaped base material 221 that is long in the longitudinal direction (X-axis direction), a non-magnetic layer 222 provided on one main surface of the base material 221, a magnetic layer 223 provided on the non-magnetic layer 222, and a back layer 224 provided on the other main surface of the base material 221. Note that the back layer 224 may be provided as necessary and may be omitted.

[0081] FIG. 20 is a schematic view of the magnetic tape 22 as seen from above. Referring to FIG. 20, the magnetic layer 223 has a plurality of data bands d (data bands d0 to d3) that are long in the longitudinal direction (X-axis direction) where data signals are written, and a plurality of servo bands s (servo bands s0 to s4) that are long in the longitudinal direction where servo signals are written. The servo bands s are arranged at positions sandwiching each data band d in the width direction (Y-axis direction). Since the servo bands s are arranged at positions sandwiching the data bands d, the number of servo bands s is one more than the number of data bands d. In the example shown in FIG. 20, an example is shown where the number of data bands d is four and the number of servo bands s is five. Note that the number of data bands d and the number of servo bands s can be changed as appropriate.

[0082] The data band d includes a plurality of recording tracks 225 that are long in the longitudinal direction and aligned in the width direction. The data signal is recorded in the recording track 225 along the recording track 225. The servo band s includes a servo signal recording pattern 226 of a predetermined pattern in which a servo signal is recorded by a servo signal recording device (not shown).

[0083] In the magnetic tape 22 configured as described above, since the data bands where data signals are recorded are arranged in the tape width direction, the distance between adjacent data bands d may vary due to the expansion of the tape width, and there is a possibility that stable recording and reproduction cannot be performed.

[0084] Therefore, in the present embodiment, in order to suppress the deformation of the reel hub 6 caused by the winding of the magnetic tape 22, the reel hub 6 is formed of an insert molding of a metal ring 610. For this reason, compared with the case where the reel hub is made of a plastic material integrally formed with the lower flange, the rigidity of the reel hub 6 is increased, and deformation caused by the winding pressure of the magnetic tape 22 or the storage environment of the tape cartridge 1 can be suppressed. As a result, since the width variation in the EOT region of the magnetic tape 22 is particularly suppressed, stable recording and reproduction can be performed.

[0085] [Experimental Example] The following describes the experimental examples conducted by the present inventors.

[0086] (Example 1) A metal ring made of SUS304 with a thickness of 1 mm was insert-molded with a composite resin material containing 65 wt% of inorganic fillers (glass filler and mineral filler) in PPS to produce a reel hub with an outer diameter of 44 mm ± 0.1 mm, an inner diameter of 38.85 mm ± 0.1 mm, and a height of 12.86 mm ± 0.1 mm.

[0087] ≪Hub Rigidity Evaluation≫ Subsequently, the rigidity of the produced reel hub was evaluated by a compression test. As the compression testing machine, a compression testing machine "RTG-1210" manufactured by A&D Company, Limited was used. As shown in FIG. 21, a columnar measuring element 42 with a diameter of 10 mm was attached to the load cell (1 kN) of the testing machine, and a jig 40 equipped with a flat receiving part 41 was installed on the pedestal of the testing machine. With the lower outer peripheral surface of the reel hub H supported by the receiving part 41, the tip of the measuring element 42 was brought into contact with the upper outer peripheral surface of the reel hub H, and a load of a predetermined magnitude was applied to the reel hub H in the radially inward direction (vertically downward) to measure the amount of deformation of the outer peripheral part in the radially inward direction. The test speed was 2 mm / min, and the sampling interval was 5 μm. The measured values were the amounts of deformation when the load was 100 N and 150 N.

[0088] ≪Measurement of Tape Width Change≫ An upper flange and a lower flange were attached to the produced reel hub to produce a tape reel shown in FIG. 5. A magnetic tape with a width of 12.65 mm, a total length of 960 m, and a total thickness of 5.6 μm was wound around the reel hub with a tension of 0.64 N to produce a tape wound body. Before and after storing the obtained tape wound body in an environment of a temperature of 49°C and a humidity of 80% for one week, the amount of deviation of the track position of the tape in each of the BOT, MOT, and EOT regions was measured with an LTO drive.

[0089] Here, when the tape tip is set to 0 [m], the tape lengths in the BOT, MOT, and EOT regions are in the ranges of 25 m to 85 m, 425 m to 485 m, and 885 m to 945 m, respectively. The amount of deviation of the track position is calculated from the difference between each data band dimension measured from the tracking control amount during reproduction of the data signals recorded in the data bands d0 and d3 (see FIG. 20) and its Nominal value (LTO7), and the values measured for the BOT, MOT, and EOT regions are taken as the tape width change amounts.

[0090] (Comparative Example 1) A reel hub was fabricated by injection molding using a composite resin material containing 65 wt% of inorganic fillers (glass filler and mineral filler) in PPS. The reel hub had an outer diameter of 44 mm ± 0.1 mm, an inner diameter of 38.85 mm ± 0.1 mm, and a height of 12.86 mm ± 0.1 mm.

[0091] The rigidity of this reel hub was measured in the same manner as in Example 1. An upper flange and a lower flange were attached to the fabricated reel hub to produce a tape reel. A magnetic tape with a width of 12.65 mm, a total length of 960 m, and a total thickness of 5.6 μm was wound around the reel hub with a tension of 0.64 N to produce a tape wound body. Before and after storing the obtained tape wound body in an environment of a temperature of 49°C and a humidity of 80% for one week, the amount of deviation of the track position of the tape in each of the BOT, MOT, and EOT regions was measured in the same manner as in Experimental Example 1.

[0092] Table 1 shows the constituent materials and hub rigidity of the reel hubs in Example 1 and Comparative Example 1, as well as the evaluation results of the tape width change. In Table 1, “+” for the tape width change indicates an increase in width, and “-” indicates a decrease in width.

[0093]

Table 1

[0094] As shown in Table 1, according to Example 1, it was confirmed that the amount of deformation when a load of 100 N and 150 N was applied radially inward to the axial center of the outer periphery of the reel hub was smaller than that of Comparative Example 1. As a result, it was confirmed that the deformation of the reel hub with respect to the winding (winding pressure) of the magnetic tape can be suppressed smaller than that of Comparative Example 1, and in particular, the tape width variation in the EOT region can also be suppressed lower than that of Comparative Example 1.

[0095] (Example 2) A metal ring made of SUS304 with a thickness of 1 mm was insert-molded with a composite resin material containing 50 wt% of an inorganic filler (glass filler) in PC to produce a reel hub with an outer diameter of 44 mm ± 0.1 mm, an inner diameter of 38.85 mm ± 0.1 mm, and a height of 12.86 mm ± 0.1 mm. Similar to Example 1, the rigidity of the reel hub and the amount of change in the width of the magnetic tape were measured.

[0096] (Comparative Example 2) A reel hub was produced by injection molding using a composite resin material containing 50 wt% of an inorganic filler (glass filler) in PC. The reel hub had an outer diameter of 44 mm ± 0.1 mm, an inner diameter of 38.85 mm ± 0.1 mm, and a height of 12.86 mm ± 0.1 mm. Similar to Comparative Example 1, the rigidity of the reel hub and the amount of change in the width of the magnetic tape were measured.

[0097] Table 1 shows the constituent materials and hub rigidity of the reel hubs in Example 2 and Comparative Example 2, as well as the evaluation results of the tape width change. In Table 1, “+” for the tape width change indicates an increase in width, and “-” indicates a decrease in width.

[0098]

Table 2

[0099] As shown in Table 2, according to Example 2, it was confirmed that the amount of deformation when loads of 100 N and 150 N were applied radially inward to the axial center of the outer periphery of the reel hub was smaller than that of Comparative Example 2. As a result, it was confirmed that the deformation of the reel hub with respect to the winding (winding pressure) of the magnetic tape can be suppressed to be smaller than that of Comparative Example 2, and in particular, the tape width variation in the EOT region can also be suppressed to be lower than that of Comparative Example 1.

[0100] [Other Embodiments] In the above embodiments, the positioning recess 651 (first recess) and the engaging recess 652 (second recess) formed on the inner peripheral surface 61 of the reel hub 6 are each constituted by separate recesses, but it is not limited thereto. For example, as in the case of the reel hub 600 shown in FIG. 22, the engaging recess 652 may be constituted by a groove portion common to the positioning recess 651. By forming the positioning recess 651 and the engaging recess 652 with groove portions having the same shape in this way, the isotropy of the resin portion forming the inner peripheral surface of the reel hub 600 is enhanced, and the uniformity of the resin portion can be improved.

[0101] In the above embodiments, the reel hub 6 was molded by the film gate method. However, for example, the reel hub 6 may be molded by the pinpoint gate method as shown in FIGS. 23A and 23B.

[0102] In the above embodiments, a magnetic tape cartridge incorporating a tape reel around which a magnetic tape is wound has been described. However, the present invention is similarly applicable to a tape reel around which a cleaning tape is wound and a cleaning tape cartridge incorporating the same.

[0103] Furthermore, in the above embodiments, a tape cartridge conforming to the LTO standard has been described. However, the present invention is not limited thereto, and is similarly applicable to a tape reel in a tape cartridge of other standards.

[0104] <Details of Magnetic Tape> As described above, the magnetic tape 22 includes a tape-shaped base material 221 that is long in the longitudinal direction (X-axis direction), a non-magnetic layer 222 provided on one main surface of the base material 221, a magnetic layer 223 provided on the non-magnetic layer 222, and a back layer 224 provided on the other main surface of the base material 221 (see FIG. 7). Hereinafter, the details of each part will be described (reference numerals are omitted).

[0105] [Base material] The base material has a long film shape. The upper limit value of the average thickness of the base material is preferably 4.2 μm or less, more preferably 3.8 μm or less, and even more preferably 3.4 μm or less. When the upper limit value of the average thickness of the base material is 4.2 μm or less, the recording capacity that can be recorded in one tape cartridge can be increased compared to a general magnetic recording medium.

[0106] The average thickness of the base material is obtained as follows. First, a 1 / 2-inch wide magnetic recording medium is prepared, cut into a length of 250 mm, and a sample is produced. Subsequently, the layers other than the base material of the sample (i.e., the non-magnetic layer, the magnetic layer, and the back layer) are removed with a solvent such as MEK (methyl ethyl ketone) or dilute hydrochloric acid. Next, using a laser hologauge manufactured by Mitutoyo Corporation as a measuring device, the thickness of the sample (base material) is measured at five or more positions, and their measured values are simply averaged (arithmetic mean) to calculate the average thickness of the base material. Note that the measurement positions are randomly selected from the sample.

[0107] The base material includes at least one of, for example, polyesters, polyolefins, cellulose derivatives, vinyl resins, and other polymer resins. When the base material includes two or more of the above materials, the two or more materials may be mixed, copolymerized, or laminated.

[0108] The polyesters include, for example, at least one of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PCT (policyclohexylene dimethylene terephthalate), PEB (polyethylene - p - oxybenzoate), and polyethylene bisphenoxy carboxylate.

[0109] The polyolefins include, for example, at least one of PE (polyethylene) and PP (polypropylene). The cellulose derivatives include, for example, at least one of cellulose diacetate, cellulose triacetate, CAB (cellulose acetate butyrate), and CAP (cellulose acetate propionate). The vinyl - based resins include, for example, at least one of PVC (polyvinyl chloride) and PVDC (polyvinylidene chloride).

[0110] The other polymer resins include, for example, at least one of PA (polyamide, nylon), aromatic PA (aromatic polyamide, aramid), PI (polyimide), aromatic PI (aromatic polyimide), PAI (polyamideimide), aromatic PAI (aromatic polyamideimide), PBO (polybenzoxazole, for example, Zylon (registered trademark)), polyether, PEK (polyether ketone), polyether ester, PES (polyether sulfone), PEI (polyether imide), PSF (polysulfone), PPS (polyphenylene sulfide), PC (polycarbonate), PAR (polyarylate), and PU (polyurethane).

[0111] [Magnetic layer] The magnetic layer is a recording layer for recording data signals. It contains magnetic powder, binder, conductive particles, etc. The magnetic layer may further contain additives such as lubricants, abrasives, rust preventives, etc. as required. The magnetic layer has a surface provided with a large number of pores. Lubricants are stored in these large number of pores. The large number of pores are preferably extended in a direction perpendicular to the surface of the magnetic layer.

[0112] The perpendicular orientation degree of the magnetic layer (without demagnetizing field correction; the same applies hereinafter) may be, for example, 65% or more. Also, the longitudinal orientation degree of the magnetic layer is set to 35% or less. The thickness of the magnetic layer is typically set to be 35 nm or more and 90 nm or less. By setting the thickness of the magnetic layer to be 35 nm or more and 90 nm or less in this way, the electromagnetic conversion characteristics can be improved.

[0113] The thickness of the magnetic layer can be obtained, for example, as follows. First, the magnetic recording medium is thinly processed perpendicular to its main surface to produce a sample piece, and the cross-section of the test piece is observed under the following conditions using a transmission electron microscope (TEM). Apparatus: TEM (H9000NAR manufactured by Hitachi, Ltd.) Accelerating voltage: 300 kV Magnification: 100,000 times

[0114] Next, using the obtained TEM image, the thickness of the magnetic layer is measured at at least 10 positions or more in the longitudinal direction of the magnetic recording medium, and then their measured values are simply averaged (arithmetic mean) to obtain the thickness of the magnetic layer. The measurement positions shall be randomly selected from the test piece.

[0115] (Magnetic powder) The magnetic powder includes a powder of nanoparticles containing ε-iron oxide (hereinafter referred to as "ε-iron oxide particles"). Even if the ε-iron oxide particles are fine particles, a high coercive force can be obtained. It is preferable that the ε-iron oxide contained in the ε-iron oxide particles is preferentially crystal-oriented in the thickness direction (perpendicular direction) of the magnetic recording medium.

[0116] The ε-iron oxide particles have a spherical or substantially spherical shape, or a cubic or substantially cubic shape. Since the ε-iron oxide particles have the above-described shape, when using ε-iron oxide particles as magnetic particles, compared with the case of using hexagonal plate-shaped barium ferrite particles as magnetic particles, the contact area between particles in the thickness direction of the magnetic recording medium can be reduced, and aggregation between particles can be suppressed. Therefore, the dispersibility of the magnetic powder can be enhanced, and a better SNR (Signal-to-Noise Ratio) can be obtained.

[0117] The ε-iron oxide particles have a core-shell structure. Specifically, the ε-iron oxide particles include a core portion and a shell portion having a two-layer structure provided around the core portion. The shell portion having a two-layer structure includes a first shell portion provided on the core portion and a second shell portion provided on the first shell portion. The core portion contains ε-iron oxide. The ε-iron oxide contained in the core portion preferably has ε-Fe2O3 crystals as the main phase, and more preferably consists of single-phase ε-Fe2O3.

[0118] The first shell portion covers at least a part of the periphery of the core portion. Specifically, the first shell portion may partially cover the periphery of the core portion, or may cover the entire periphery of the core portion. From the viewpoint of making the exchange coupling between the core portion and the first shell portion sufficient and improving the magnetic properties, it is preferable to cover the entire surface of the core portion 21. The first shell portion is a so-called soft magnetic layer and contains, for example, a soft magnetic material such as α-Fe, Ni-Fe alloy or Fe-Si-Al alloy. α-Fe may be obtained by reducing the ε-iron oxide contained in the core portion 21.

[0119] The second shell part is an oxide film as an antioxidant layer. The second shell part contains α-iron oxide, aluminum oxide, or silicon oxide. The α-iron oxide contains at least one iron oxide of, for example, Fe3O4, Fe2O3, and FeO. When the first shell part contains α-Fe (soft magnetic material), the α-iron oxide may be obtained by oxidizing the α-Fe contained in the first shell part 22a.

[0120] By having the first shell part as described above, the ε-iron oxide particles can keep the coercive force Hc of the core part alone at a large value to ensure thermal stability, while adjusting the coercive force Hc of the ε-iron oxide particles (core-shell particles) as a whole to a coercive force Hc suitable for recording. Also, by having the second shell part as described above, in the manufacturing process of the magnetic recording medium and before that process, when the ε-iron oxide particles are exposed to the air and rust or the like occurs on the particle surface, it is possible to suppress the deterioration of the characteristics of the ε-iron oxide particles. Therefore, deterioration of the characteristics of the magnetic recording medium can be suppressed.

[0121] The average particle size (average maximum particle size) of the magnetic powder is preferably 22 nm or less, more preferably 8 nm or more and 22 nm or less, and even more preferably 12 nm or more and 22 nm or less.

[0122] The average aspect ratio of the magnetic powder is preferably 1 or more and 2.5 or less, more preferably 1 or more and 2.1 or less, and even more preferably 1 or more and 1.8 or less. When the average aspect ratio of the magnetic powder is in the range of 1 or more and 2.5 or less, aggregation of the magnetic powder can be suppressed, and when the magnetic powder is vertically oriented in the formation process of the magnetic layer, the resistance applied to the magnetic powder can be suppressed. Therefore, the vertical orientation of the magnetic powder can be improved.

[0123] The average volume Vave (particle volume) of the magnetic powder is preferably 2300 nm 3 or less, more preferably 2200 nm 3 or less, more preferably 2100 nm 3 or less, more preferably 1950 nm 3More preferably, it is 1600 nm or less 3 Even more preferably, it is 1300 nm or less 3 The average volume Vave of the magnetic powder is 2300 nm or less. When the average volume Vave of the magnetic powder is 2300 nm or less, the half-value width of the isolated waveform in the reproduced waveform of the servo signal can be narrowed (195 nm or less), and the peak of the reproduced waveform of the servo signal can be sharpened. As a result, since the reading accuracy of the servo signal is improved, the number of recording tracks can be increased and the recording density of data can be improved. Note that the lower limit of the volume is not particularly limited as long as the average volume Vave of the magnetic powder is smaller, the better. For example, the lower limit is 1000 nm 3 or more. 3

[0124] The average particle size, average aspect ratio, and average volume Vave of the magnetic powder are obtained as follows (for example, when the magnetic powder has a shape such as a sphere like ε-iron oxide particles). First, the magnetic recording medium to be measured is processed by the FIB (Focused Ion Beam) method or the like to produce a thin slice, and the cross-section of the thin slice is observed by TEM. Next, 50 magnetic powders are randomly selected from the taken TEM photograph, and the major axis length DL and minor axis length DS of each magnetic powder are measured. Here, the major axis length DL means the maximum of the distances between two parallel lines drawn from all angles so as to be in contact with the contour of the magnetic powder (the so-called maximum Feret diameter). On the other hand, the minor axis length DS means the maximum of the lengths of the magnetic powder in the direction perpendicular to the major axis of the magnetic powder.

[0125] Subsequently, the major axis lengths DL of the 50 measured magnetic powders are simply averaged (arithmetic mean) to obtain the average major axis length DLave. And the average major axis length DLave thus obtained is taken as the average particle size of the magnetic powder. Also, the minor axis lengths DS of the 50 measured magnetic powders are simply averaged (arithmetic mean) to obtain the average minor axis length DSave. Next, the average aspect ratio (DLave / DSave) of the magnetic powder is obtained from the average major axis length DLave and the average minor axis length DSave.

[0126] ​Next, the average volume Vave (particle volume) of the magnetic powder is obtained from the following formula using the average major axis length DLave. Vave = π / 6 × DLave 3

[0127] In the description here, the case where the ε-iron oxide particles have a shell portion with a two-layer structure has been described, but the ε-iron oxide particles may have a shell portion with a single-layer structure. In this case, the shell portion has the same configuration as the first shell portion. However, from the viewpoint of suppressing the deterioration of the characteristics of the ε-iron oxide particles, as described above, it is preferable that the ε-iron oxide particles have a shell portion with a two-layer structure.

[0128] In the above description, the case where the ε-iron oxide particles have a core-shell structure has been described, but the ε-iron oxide particles may contain an additive instead of having a core-shell structure, or may have a core-shell structure and contain an additive. In this case, a part of Fe of the ε-iron oxide particles is replaced by the additive. Since the coercivity Hc of the entire ε-iron oxide particles can be adjusted to a coercivity Hc suitable for recording by the ε-iron oxide particles containing the additive, the ease of recording can be improved. The additive is a metal element other than iron, preferably a trivalent metal element, more preferably at least one of Al, Ga, and In, and even more preferably at least one of Al and Ga.

[0129] Specifically, the ε-iron oxide containing the additive is ε-Fe 2-x M x O3 crystal (where M is a metal element other than iron, preferably a trivalent metal element, more preferably at least one of Al, Ga, and In, and even more preferably at least one of Al and Ga. x is, for example, 0 < x < 1.).

[0130] The magnetic powder may contain a powder of nanoparticles containing hexagonal ferrite (hereinafter referred to as "hexagonal ferrite particles"). The hexagonal ferrite particles have, for example, a hexagonal plate shape or a substantially hexagonal plate shape. The hexagonal ferrite preferably contains at least one of Ba, Sr, Pb, and Ca, more preferably at least one of Ba and Sr. Specifically, the hexagonal ferrite may be, for example, barium ferrite or strontium ferrite. Barium ferrite may further contain at least one of Sr, Pb, and Ca in addition to Ba. Strontium ferrite may further contain at least one of Ba, Pb, and Ca in addition to Sr.

[0131] More specifically, the hexagonal ferrite has an average composition represented by the general formula MFe 12 O 19 wherein M is at least one metal of, for example, Ba, Sr, Pb, and Ca, preferably at least one metal of Ba and Sr. M may be a combination of Ba and one or more metals selected from the group consisting of Sr, Pb, and Ca. Also, M may be a combination of Sr and one or more metals selected from the group consisting of Ba, Pb, and Ca. In the above general formula, a part of Fe may be substituted with another metal element.

[0132] When the magnetic powder contains a powder of hexagonal ferrite particles, the average particle size of the magnetic powder is preferably 50 nm or less, more preferably 10 nm or more and 40 nm or less, and even more preferably 15 nm or more and 30 nm or less. When the magnetic powder contains a powder of hexagonal ferrite particles, the average aspect ratio of the magnetic powder and the average volume Vave of the magnetic powder are as described above.

[0133] The average particle size, average aspect ratio, and average volume Vave of the magnetic powder are determined as follows (for example, when the magnetic powder has a plate-like shape such as hexagonal ferrite). First, the magnetic recording medium to be measured is processed by the FIB method or the like to produce a thin slice, and the cross-section of the thin slice is observed by TEM. Next, 50 magnetic powders oriented at an angle of 75 degrees or more with respect to the horizontal direction are randomly selected from the taken TEM photograph, and the maximum plate thickness DA of each magnetic powder is measured. Subsequently, the maximum plate thicknesses DA of the 50 measured magnetic powders are simply averaged (arithmetic mean) to obtain the average maximum plate thickness DAave.

[0134] Next, the surface of the magnetic layer of the magnetic recording medium is observed by TEM. Next, 50 magnetic powders are randomly selected from the taken TEM photograph, and the maximum plate diameter DB of each magnetic powder is measured. Here, the maximum plate diameter DB means the maximum distance (so-called maximum Feret diameter) between two parallel lines drawn from all angles so as to be in contact with the contour of the magnetic powder. Subsequently, the maximum plate diameters DB of the 50 measured magnetic powders are simply averaged (arithmetic mean) to obtain the average maximum plate diameter DBave. Then, the average maximum plate diameter DBave thus obtained is taken as the average particle size of the magnetic powder. Next, the average aspect ratio (DBave / DAave) of the magnetic powder is obtained from the average maximum plate thickness DAave and the average maximum plate diameter DBave.

[0135] Next, the average volume Vave (particle volume) of the magnetic powder is obtained from the following formula using the average maximum plate thickness DAave and the average maximum plate diameter DBave. Vave = 3√3 / 8 × DAave × DBave 2

[0136] The magnetic powder may contain a powder of nanoparticles containing Co-containing spinel ferrite (hereinafter referred to as "cobalt ferrite particles"). The cobalt ferrite particles preferably have uniaxial anisotropy. The cobalt ferrite particles have, for example, a cubic shape or a substantially cubic shape. The Co-containing spinel ferrite may further contain at least one of Ni, Mn, Al, Cu, and Zn in addition to Co.

[0137] Cobalt-containing spinel ferrite has an average composition represented by, for example, the following formula (1). Co x M y Fe2O Z ···(1) (However, in formula (1), M is at least one metal among, for example, Ni, Mn, Al, Cu, and Zn. x is a value in the range of 0.4 ≦ x ≦ 1.0. y is a value in the range of 0 ≦ y ≦ 0.3. However, x and y satisfy the relationship (x + y) ≦ 1.0. z is a value in the range of 3 ≦ z ≦ 4. A part of Fe may be substituted with other metal elements.)

[0138] When the magnetic powder contains cobalt ferrite particle powder, the average particle size of the magnetic powder is preferably 25 nm or less, more preferably 23 nm or less. When the magnetic powder contains cobalt ferrite particle powder, the average aspect ratio of the magnetic powder is determined by the above method, and the average volume Vave of the magnetic powder is determined by the method shown below.

[0139] In addition, when the magnetic powder has a cubic shape such as cobalt ferrite particles, the average volume Vave (particle volume) of the magnetic powder can be obtained as follows. First, the surface of the magnetic layer of the magnetic recording medium is observed by TEM. Next, 50 magnetic powders are randomly selected from the taken TEM photograph, and the side length DC of each magnetic powder is measured. Subsequently, the side lengths DC of the 50 measured magnetic powders are simply averaged (arithmetic mean) to obtain the average side length DCave. Next, the average volume Vave (particle volume) of the magnetic powder is obtained from the following formula using the average side length DCave. Vave = DCave 3

[0140] (Binder) As the binder, resins having a structure with a cross-linking reaction imparted thereto, such as polyurethane-based resins and vinyl chloride-based resins, are preferred. However, the binder is not limited to these, and other resins may be appropriately blended according to the physical properties required for the magnetic recording medium. The resin to be blended is not particularly limited as long as it is a resin generally used in a coating-type magnetic recording medium.

[0141] For example, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, acrylate-vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, acrylate-vinylidene chloride copolymer, methacrylate-vinylidene chloride copolymer, methacrylate-vinyl chloride copolymer, methacrylate-ethylene copolymer, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-butadiene copolymer, polyamide resin, polyvinyl butyral, cellulose derivatives (cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, nitrocellulose), styrene-butadiene copolymer, polyester resin, amino resin, synthetic rubber, etc. can be mentioned.

[0142] Examples of thermosetting resins or reactive resins include phenol resins, epoxy resins, urea resins, melamine resins, alkyd resins, silicone resins, polyamine resins, urea formaldehyde resins, etc.

[0143] In addition, polar functional groups such as -SO3M, -OSO3M, -COOM, and P=O(OM)2 may be introduced into each of the above-mentioned binders for the purpose of improving the dispersibility of magnetic powder. Here, in the formula, M is a hydrogen atom or an alkali metal such as lithium, potassium, or sodium.

[0144] Furthermore, as the polar functional group, -NR1R2, -NR1R2R3 + X - Side chain type having a terminal group of >NR1R2 + X - Main chain type of can be mentioned. Here, in the formula, R1, R2, and R3 are a hydrogen atom or a hydrocarbon group, and X - Is a halogen element ion such as fluorine, chlorine, bromine, iodine, or an inorganic or organic ion. In addition, examples of the polar functional group include -OH, -SH, -CN, epoxy group, etc.

[0145] (Lubricant) The lubricant preferably contains a compound represented by the following general formula (1) and a compound represented by the following general formula (2). By the lubricant containing these compounds, the kinetic friction coefficient of the surface of the magnetic layer can be particularly reduced. Therefore, the running performance of the magnetic recording medium can be further improved. CH3(CH2) n COOH ···(1) (However, in general formula (1), n is an integer selected from the range of 14 or more and 22 or less.) CH3(CH2) p COO(CH2) q CH3···(2) (However, in general formula (2), p is an integer selected from the range of 14 or more and 22 or less, and q is an integer selected from the range of 2 or more and 5 or less.)

[0146] (Additive) The magnetic layer may further contain, as non-magnetic reinforcing particles, aluminum oxide (α, β or γ alumina), chromium oxide, silicon oxide, diamond, garnet, emery, boron nitride, titanium carbide, silicon carbide, titanium carbide, titanium oxide (rutile type or anatase type titanium oxide), etc.

[0147] [Non-magnetic layer] The non-magnetic layer contains non-magnetic powder and a binder. The non-magnetic layer may contain additives such as electrodynamic particles, lubricants, curing agents, rust preventives, etc. as necessary.

[0148] The thickness of the non-magnetic layer is preferably 0.6 μm or more and 2.0 μm or less, more preferably 0.8 μm or more and 1.4 μm or less. The thickness of the non-magnetic layer can be determined by the same method as the method for determining the thickness of the magnetic layer (for example, TEM). Note that the magnification of the TEM image is appropriately adjusted according to the thickness of the non-magnetic layer.

[0149] (Non-magnetic powder) The non-magnetic powder contains at least one of, for example, inorganic particle powder or organic particle powder. The non-magnetic powder may contain a carbon material such as carbon black. Note that one type of non-magnetic powder may be used alone, or two or more types of non-magnetic powders may be used in combination. The inorganic particles include, for example, metals, metal oxides, metal carbonates, metal sulfates, metal nitrides, metal carbides, or metal sulfides. Examples of the shape of the non-magnetic powder include various shapes such as acicular, spherical, cubic, and plate-like, but are not limited thereto.

[0150] (Binder) The binder is the same as the above-described magnetic layer.

[0151] [Back layer] The back layer contains non-magnetic powder and a binder. The back layer may contain additives such as a lubricant, a curing agent, and an antistatic agent as necessary. As the non-magnetic powder and the binder, the same materials as those used for the above-described non-magnetic layer are used.

[0152] (Non-magnetic powder) The average particle size of the non-magnetic powder is preferably 10 nm or more and 150 nm or less, more preferably 15 nm or more and 110 nm or less. The average particle size of the non-magnetic powder is determined in the same manner as the average particle size D of the above-described magnetic powder. The non-magnetic powder may contain non-magnetic powder having two or more particle size distributions.

[0153] The upper limit value of the average thickness of the back layer is preferably 0.6 μm or less. When the upper limit value of the average thickness of the back layer is 0.6 μm or less, even when the average thickness of the magnetic recording medium is 5.6 μm, the thickness of the non-magnetic layer and the substrate can be kept thick, so that the running stability of the magnetic recording medium in the recording and reproducing apparatus can be maintained. The lower limit value of the average thickness of the back layer is not particularly limited, but is, for example, 0.2 μm or more.

[0154] The average thickness of the back layer is obtained as follows. First, a 1 / 2-inch-wide magnetic recording medium is prepared, cut into a length of 250 mm, and a sample is produced. Next, using a laser hologauge manufactured by Mitutoyo Corporation as a measuring device, the thickness of the sample is measured at five or more points, and these measured values are simply averaged (arithmetic mean) to calculate the average value t T [μm] of the magnetic recording medium. The measurement positions shall be randomly selected from the sample. Subsequently, the back layer of the sample is removed with a solvent such as MEK (methyl ethyl ketone) or dilute hydrochloric acid. Then, again using the above laser hologauge, the thickness of the sample is measured at five or more points, and these measured values are simply averaged (arithmetic mean) to calculate the average value t B [μm] of the magnetic recording medium after removing the back layer. The measurement positions shall be randomly selected from the sample. Then, the average thickness t b [μm] of the back layer is obtained from the following formula. t b [μm]=t T [μm]-t B [μm]

[0155] The back layer has a surface provided with a large number of protrusions. The large number of protrusions are for forming a large number of holes on the surface of the magnetic layer when the magnetic recording medium is wound in a roll shape. The large number of holes are composed of, for example, a large number of non-magnetic particles protruding from the surface of the back layer.

[0156] In the description herein, the case where a large number of protrusions provided on the surface of the back layer are transferred to the surface of the magnetic layer to form a large number of holes in the surface of the magnetic layer has been described. However, the method for forming the large number of holes is not limited thereto. For example, by adjusting the type of solvent contained in the paint for forming the magnetic layer and the drying conditions of the paint for forming the magnetic layer, etc., a large number of holes may be formed on the surface of the magnetic layer.

[0157] [Average thickness of the magnetic recording medium] The upper limit value of the average thickness (average total thickness) of the magnetic recording medium is preferably 5.6 μm or less, more preferably 5.0 μm or less, still more preferably 4.6 μm or less, and even more preferably 4.4 μm or less. When the average thickness of the magnetic recording medium is 5.6 μm or less, the recording capacity that can be recorded in the cartridge can be increased compared to a general magnetic recording medium. The lower limit value of the average thickness of the magnetic recording medium is not particularly limited, but is, for example, 3.5 μm or more.

[0158] The average thickness of the magnetic recording medium is obtained by the procedure described in the method for obtaining the average thickness of the back layer described above.

[0159] Note that the present technology can also have the following configuration. (1) A first flange, a second flange, and a reel hub disposed between the first flange and the second flange around which a tape is wound and comprising wherein the reel hub is a cylindrical metal ring, and a molded body made of synthetic resin having a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring, wherein the first resin portion has a plurality of first recesses formed at intervals in the circumferential direction of the metal ring Tape cartridge. (2) The tape cartridge according to (1) above, The plurality of first concave portions are groove portions extending in the axial direction of the metal ring. Tape cartridge. (3) The tape cartridge according to (2) above, The plurality of first concave portions are formed from one axial end of the first resin portion to the vicinity of the other axial end of the first resin portion. Tape cartridge. (4) The tape cartridge according to (2) or (3) above, The molded body further has a third resin portion formed on a surface on one axial end side of the metal ring. The third resin portion has a plurality of hole portions formed at intervals in the circumferential direction of the metal ring. Tape cartridge. (5) The tape cartridge according to any one of (2) to (4) above, The first flange has a plurality of protrusions protruding toward one axial end of the first resin portion. The first resin portion further has a plurality of second concave portions that engage with the plurality of protrusions. Tape cartridge. (6) The tape cartridge according to (5) above, The plurality of second concave portions are groove portions common to the plurality of first concave portions. Tape cartridge. (7) The tape cartridge according to any one of (1) to (6) above, The first flange has a plurality of first engaging portions provided on the inner diameter side of the reel hub. The second flange has a plurality of second engaging portions provided on the inner diameter side of the reel hub and engaging with the plurality of first engaging portions. The reel hub is disposed between the first flange and the second flange that are mutually coupled via the plurality of first engaging portions and the plurality of second engaging portions. Tape cartridge. (8) A first flange, A second flange, A reel hub disposed between the first flange and the second flange; comprising: The reel hub includes: a cylindrical metal ring; a molded body made of synthetic resin having a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring; The first resin portion has a plurality of first recesses formed at intervals in the circumferential direction of the metal ring; a tape reel. (9) Dispose the metal ring in a first mold having a cylindrical portion facing the inner peripheral surface of the metal ring, a first base portion formed integrally with the cylindrical portion and facing one axial end of the metal ring, and a plurality of protrusions extending along the axial direction and protruding from the outer peripheral surface of the cylindrical portion toward the inner peripheral surface of the metal ring; Combine a second mold having a cylindrical portion facing the outer peripheral surface of the metal ring and a second base portion formed integrally with the cylindrical portion and facing the other axial end of the metal ring with the first mold; Inject a synthetic resin material between the outer peripheral portion of the cylindrical portion and the inner peripheral surface of the cylindrical portion through an injection port formed between the cylindrical portion and the second base portion; A method for manufacturing a reel hub. (10) The method for manufacturing a reel hub according to (9) above, wherein the injection port is formed over the entire circumference of the other end of the metal ring; A method for manufacturing a reel hub. (11) The method for manufacturing a reel hub according to (9) or (10) above, wherein the first base portion has a plurality of protrusions that support the surface on the one end side of the metal ring; A method for manufacturing a reel hub.

Explanation of reference numerals

[0160] 1... tape cartridge 6,600... reel hub 7... upper flange (second flange) 8…Lower flange (first flange) 22…Magnetic tape 91…First mold 92…Second mold 610…Metal ring 620…Formed body 621…First resin part 622…Second resin part 623…Third resin part 624…Fourth resin part 651…Positioning recess (first recess) 652…Engaging recess (second recess) 653…Hole part 911…First base part 912…Core part (columnar part) 913…Rib part 914…Protrusion 915…Projection

Claims

1. A first flange, a second flange, and a reel hub disposed between the first flange and the second flange and around which a tape is wound, a tape reel comprising, wherein the reel hub is a cylindrical metal ring, and a molded body made of synthetic resin having a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring, the first resin portion having a plurality of first recesses formed at intervals in the circumferential direction of the metal ring, the plurality of first recesses being groove portions extending in the axial direction of the metal ring and formed from one axial end of the first resin portion to near the other axial end of the first resin portion a tape cartridge.

2. A first flange, a second flange, and a reel hub disposed between the first flange and the second flange and around which a tape is wound, a tape reel comprising, wherein the reel hub is a cylindrical metal ring, and a molded body made of synthetic resin having a first resin portion formed on the inner peripheral surface of the metal ring and a second resin portion formed on the outer peripheral surface of the metal ring, the first resin portion having a plurality of first recesses formed at intervals in the circumferential direction of the metal ring, the plurality of first recesses being groove portions extending in the axial direction of the metal ring, the molded body further having a third resin portion formed on a surface on one axial end side of the metal ring, the third resin portion having a plurality of holes formed at intervals in the circumferential direction of the metal ring a tape cartridge.

3. The tape cartridge according to claim 1 or 2, wherein the first flange has a plurality of protrusions protruding toward one axial end of the first resin portion, and the first resin portion further has a plurality of second recesses that engage with the plurality of protrusions a tape cartridge.

4. The tape cartridge according to claim 3, wherein the plurality of second recesses are groove portions common to the plurality of first recesses a tape cartridge.

5. The tape cartridge according to any one of claims 1 to 4, wherein the first flange has a plurality of first engaging portions provided on the inner diameter side of the reel hub, and the second flange has a plurality of second engaging portions provided on the inner diameter side of the reel hub and engaging with the plurality of first engaging portions The reel hub is disposed between the first flange and the second flange that are coupled to each other via the plurality of first engaging portions and the plurality of second engaging portions. Tape cartridge. **Claim 6** A first flange, A second flange, A reel hub disposed between the first flange and the second flange, comprising: The reel hub is a cylindrical metal ring, and a molded body made of synthetic resin having a first resin portion formed on an inner peripheral surface of the metal ring and a second resin portion formed on an outer peripheral surface of the metal ring. The first resin portion has a plurality of first recesses formed at intervals in a circumferential direction of the metal ring. The plurality of first recesses are groove portions extending in an axial direction of the metal ring, and are formed from one axial end of the first resin portion to near the other axial end of the first resin portion. Tape reel. **Claim 7** A first flange, A second flange, A reel hub disposed between the first flange and the second flange, comprising: The reel hub is a cylindrical metal ring, and a molded body made of synthetic resin having a first resin portion formed on an inner peripheral surface of the metal ring and a second resin portion formed on an outer peripheral surface of the metal ring. The first resin portion has a plurality of first recesses formed at intervals in a circumferential direction of the metal ring. The plurality of first recesses are groove portions extending in an axial direction of the metal ring. The molded body further has a third resin portion formed on a surface on one axial end side of the metal ring, and the third resin portion has a plurality of holes formed at intervals in a circumferential direction of the metal ring. Tape reel. **Claim 8** A first mold having a cylindrical portion facing an inner peripheral surface of a metal ring, a first base portion integrally formed with the cylindrical portion and facing one axial end of the metal ring and having a plurality of protruding portions supporting the surface on the one end side of the metal ring, and a plurality of ridges extending along the axial direction and protruding from an outer peripheral surface of the cylindrical portion toward the inner peripheral surface of the metal ring, wherein the metal ring is disposed. A second mold having a cylindrical portion facing an outer peripheral surface of the metal ring and a second base portion integrally formed with the cylindrical portion and facing the other axial end of the metal ring is combined with the first mold. Inject a synthetic resin material between the outer peripheral portion of the cylindrical portion and the inner peripheral surface of the cylindrical portion through an injection port formed between the cylindrical portion and the second base portion. A method for manufacturing a reel hub.

9. The method for manufacturing a reel hub according to claim 8, The injection port is formed over the entire circumference of the other end of the metal ring. A method for manufacturing a reel hub.

Images