U.S. patent application number 10/891067 was filed with the patent office on 2005-02-17 for magnetic tape drive.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Asai, Masahiko, Nakao, Toru.
Application Number | 20050035241 10/891067 |
Document ID | / |
Family ID | 33562791 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050035241 |
Kind Code |
A1 |
Nakao, Toru ; et
al. |
February 17, 2005 |
Magnetic tape drive
Abstract
A magnetic tape drive is equipped with a travel device for
running a magnetic tape and a plurality of guides for guiding the
magnetic tape, which is running, along a predetermined route. Each
of the guides has a roller portion and a flange portion. A surface
hardening treatment is dispensed to a guide out of the guides where
a ratio of a peripheral speed of the guide for a running speed of
the magnetic tape is not more than 0.9.
Inventors: |
Nakao, Toru; (Kanagawa,
JP) ; Asai, Masahiko; (Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
33562791 |
Appl. No.: |
10/891067 |
Filed: |
July 15, 2004 |
Current U.S.
Class: |
242/615.4 ;
G9B/15.078; G9B/15.092 |
Current CPC
Class: |
G11B 15/605 20130101;
G11B 15/67 20130101 |
Class at
Publication: |
242/615.4 |
International
Class: |
B65H 023/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 13, 2003 |
JP |
2003-292925 |
Claims
What is claimed is:
1. A magnetic tape drive comprising: a travel device for running a
magnetic tape; and a plurality of guides for guiding said magnetic
tape, which is running, along a predetermined route, wherein each
of said guides comprises a roller portion and a flange portion,
wherein a surface hardening treatment is dispensed to a guide out
of said guides, and wherein a ratio of a peripheral speed of the
guide for a running speed of said magnetic tape is not more than
0.9.
2. A magnetic tape drive according to claim 1, wherein a wrap angle
of said magnetic tape is not more than 90 degrees in a guide, and
wherein said ratio of a peripheral speed of the guide is not more
than 0.9.
3. A magnetic tape drive according to claim 1, wherein a surface
hardening treatment is dispensed to all surface of each of said
guides.
4. A magnetic tape drive according to claim 2, wherein a surface
hardening treatment is dispensed to all surface of each of said
guides.
5. A magnetic tape drive according to claim 1, wherein a surface
hardening treatment is dispensed to nothing but an inner surface of
a flange portion arising from a periphery of a roller portion of
each of said guides.
6. A magnetic tape drive according to claim 2, wherein a surface
hardening treatment is dispensed to nothing but an inner surface of
a flange portion arising from a periphery of a roller portion of
each of said guides.
7. A magnetic tape drive according to claim 1, wherein a roller
portion and flange portion of each of said guides is configured of
different members and said flange portion is joined to said roller
portion, and wherein a surface hardening treatment is dispensed to
the flange portion.
8. A magnetic tape drive according to claim 2, wherein a roller
portion and flange portion of each of said guides is configured of
different members and said flange portion is joined to said roller
portion, and wherein a surface hardening treatment is dispensed to
the flange portion.
9. A magnetic tape drive according to claim 1, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
10. A magnetic tape drive according to claim 2, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
11. A magnetic tape drive according to claim 3, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
12. A magnetic tape drive according to claim 4, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
13. A magnetic tape drive according to claim 5, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
14. A magnetic tape drive according to claim 6, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
15. A magnetic tape drive according to claim 7, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
16. A magnetic tape drive according to claim 8, wherein a material
of a hardened layer formed on said guides by said surface hardening
treatment is any of titan nitride, chromium nitride, titan aluminum
nitride, tungsten carbide-cobalt, and diamond-like carbon.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a magnetic tape drive for
recording/reproducing magnetic information for a magnetic tape.
[0003] 2. Description of the Related Art
[0004] A magnetic tape drive is equipped with a travel device for
running a magnetic tape and a plurality of guides for guiding the
magnetic tape, which runs, along a predetermined route (for
example, see paraphrase 0058 and FIG. 1 in Japanese Patent
Laid-Open Publication 2002-530791). In this magnetic tape drive a
running magnetic tape is designed to be hung across a plurality of
guides arranged at predetermined positions. And each of these
guides is configured, as well known, of a roller portion of a
cylindrical shape freely rotationally supported by a shaft around a
center axis and a flange portion arranged on up/down ends of each
roller.
[0005] In such the magnetic tape drive, it is designed so that
magnetic information is sent to a magnetic head while a magnetic
tape, which is received on a periphery of the roller portion, is
regulated in a lateral directional movement thereof by the flange
portion; thereby the magnetic information is recorded on the
magnetic tape; and the recorded magnetic information is
reproduced.
[0006] In the meantime, because if such the magnetic tape drive is
used for an inspection of magnetic characteristics of the magnetic
tape and a library equipping many magnetic cartridges where
magnetic information data is stored, the magnetic tape loaded on
the magnetic tape drive is in no use or nearly in no use, the
guides are remarkably abraded away by a large grinding force of the
magnetic tape. In short, for example, as shown in FIG. 9, a groove
G is dug into a flange portion 20a of a guide 20 where an edge of a
magnetic tape MT abrades as use times of a magnetic tape drive are
repeated. This tendency noticeably appears in a magnetic tape drive
where a running speed of a magnetic tape is heightened and magnetic
information is recorded/reproduced at a high speed. And such the
groove G being dug, the magnetic tape MT guided by the guide 20 is
oscillated in lateral directions (in up/down directions in FIG. 9)
by the groove G in order of a micro meter (.mu.m).
[0007] On the other hand, nowadays a track width tends to be
narrowed in order to achieve a high density recording of a magnetic
tape. As a result, when a magnetic tape drive is used, the above
oscillation of the magnetic tape becomes a cause of a tracking
error even if an oscillation width thereof is in order of the micro
meter.
[0008] Consequently, is strongly requested a magnetic tape drive,
which does not generate the tracking error, not depending on
recording density of a magnetic tape even if used over a long
period.
SUMMARY OF THE INVENTION
[0009] The inventor has found that when in each of a plurality of
guides arranged at a magnetic tape drive a ratio of a peripheral
speed of each guide for a running speed of a magnetic tape becomes
lower than a predetermined value, a flange portion of the guide is
peculiarly ground by the magnetic tape, and thereby has reached the
present invention.
[0010] A first aspect of the present invention to solve the problem
is a magnetic tape drive comprising a travel device for running a
magnetic tape and a plurality of guides guiding the magnetic tape,
which is running, along a predetermined route, and a surface
hardening treatment is dispensed to a relevant guide out of the
guides, whose ratio of a peripheral speed for a running speed of
the magnetic tape is not more than 0.9.
[0011] In the magnetic tape drive, when the travel device runs the
magnetic tape while the guides guide it along the predetermined
route, the magnetic tape is regulated by flange portions of the
guides in a movement of lateral directions thereof. In accordance
with such the magnetic tape drive, because when the running
magnetic tape is guided by the guides, the surface hardening
treatment is dispensed to the relevant guide out of the guides,
whose ratio of the peripheral speed for the running speed of the
magnetic tape is not more than 0.9, that is, the guide where a
difference between the running speed of the magnetic tape and a
rotation speed of the guide is not less than the predetermined
value, the flange portion of the relevant guide becomes difficult
to be ground by edges of the magnetic tape. Accordingly, even when
the magnetic tape drive is used over a long period, the magnetic
tape is not oscillated in the lateral directions thereof.
[0012] On the other hand, in accordance with knowledge of the
inventor a guide, where a wrap angle of the magnetic tape is not
more than 90 degrees, is remarkably bad in a rotation following
ability. Meanwhile, the wrap angle described here means a range of
a plane angle where the magnetic tape hung across a periphery of a
guide contacts the periphery, that is, a contact angle (see FIG.
2B).
[0013] Accordingly, in such the magnetic tape drive the surface
hardening treatment is preferable to be dispensed to the relevant
guide out of the guides, whose ratio of the peripheral speed for
the running speed of the magnetic tape is not more than 0.9 and
whose wrap angle of the magnetic tape is not more than 90
degrees.
[0014] Even when the magnetic tape drive is used over a long
period, it more surely suppresses an oscillation of a magnetic tape
in lateral directions thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic drawing of a magnetic tape drive
related to an embodiment of the present invention.
[0016] FIG. 2A is a perspective view showing a state around a guide
used in the magnetic tape drive of FIG. 1; FIG. 2B is a pattern
drawing showing a state where a magnetic tape contacts a guide used
in the magnetic tape drive of FIG. 1.
[0017] FIG. 3 is a partial section drawing of a guide used in the
magnetic tape drive of FIG. 1.
[0018] FIG. 4 is a schematic drawing showing arrangement positions
in a magnetic tape drive used for an abrasion resistance test of a
guide.
[0019] FIG. 5 is a pattern drawing of a guide sample provided for
an observation through a laser microscope.
[0020] FIG. 6 is a microscope photo of a guide sample (example of
the present invention).
[0021] FIG. 7 is a microscope photo of a guide sample (comparison
example).
[0022] Each of FIGS. 8A and 8B is a partial section drawing of a
guide used in a magnetic tape drive related to other
embodiments.
[0023] FIG. 9 is a conceptual drawing showing a guide used in a
conventional magnetic tape drive.
DESCRIPTION OF THE MOST PREFERRED EMBODIMENTS
[0024] Here will be described one embodiment of the present
invention related to a magnetic tape drive (hereinafter simply
referred to as a "drive") in detail, referring to the drawings as
needed. In referred drawings FIG. 1 is a schematic drawing of a
magnetic tape drive related to an embodiment of the present
invention; FIG. 2A is a perspective view showing a state around a
guide used in the magnetic tape drive of FIG. 1; FIG. 2B is a
pattern drawing showing a state where a magnetic tape contacts a
guide used in the magnetic tape drive of FIG. 1; and FIG. 3 is a
partial section drawing of a guide used in the magnetic tape drive
of FIG. 1 when the guide is cut at a plane along a rotation axis
thereof.
[0025] The drive exemplified in the embodiment is one according to
the LTO standard (Linear Tape-Open) and is designed to
record/reproduce magnetic information at a high speed even when a
magnetic tape of a magnetic tape cartridge runs in any
forward/reverse of bi-directions.
[0026] As shown in FIG. 1, a drive A related to the embodiment
comprises a first gear 11a and a second gear 11b; a reel 12; a
magnetic head 14; a first guide 15a and a second guide 15b (simply
referred to as "guide 15" when not specifying a guide); drive
motors not shown for driving the first gear 11a and the second gear
11b, respectively; and a casing 16 for housing the members 11a,
11b, 12, 14, 15a, and 15b.
[0027] The first gear 11a rotates a reel 17 of a magnetic tape
cartridge MC loaded in the drive A and is designed to rotate in any
forward/reverse of bi-directions by a drive motor not shown.
[0028] The reel 12 (hereinafter referred to as a "drive-side reel
12") winds a magnetic tape MT, which is sent out from the reel 17
(hereinafter referred to as a "cartridge-side reel 17") of the
magnetic tape cartridge MC, and sends out the magnetic tape MT,
which is wound, to the cartridge-side reel 17.
[0029] The second gear 11b rotates the drive-side reel 12 in a
direction opposite to a rotation direction of the cartridge-side
reel 17 and is designed to rotate in any forward/reverse of
bi-directions of a by a drive motor not shown.
[0030] The magnetic head 14 records magnetic information on the
magnetic tape MT, which reciprocates between the cartridge-side
reel 17 and the drive-side reel 12, and also reproduces the
recorded magnetic information. In the magnetic head 14 is used a
compound head, which comprises a read element such as a
magnetoresistive effect element and a write element such as an
electromagnetic induction element. The magnetic head 14 is arranged
so as to be able to contact the magnetic tape MT, which runs with
being guided to a predetermined route by the guide 15 described
next.
[0031] The first guide 15a and the second guide 15b guide the
magnetic tape MT, which is sent out from the magnetic tape
cartridge MC (cartridge-side reel 17), so as to head for the
drive-side reel 12 via the magnetic head 14; and otherwise guide
the magnetic tape MT, which is wound on the drive-side reel 12, so
as to head for the cartridge-side reel 17 via the magnetic head 14.
By these first guide 15a and second guide 15b is determined a
running route of the magnetic tape MT in the drive A.
[0032] As obvious jointly in reference to FIG. 2A, such the guide
15 is designed to be supported by a rotation shaft 15c, which
extends to a vertical direction of the casing 16, and to be able to
rotate around the rotation shaft 15c. And the guide 15 is designed
so that a flange portion 15e thereof regulates a movement of
lateral directions of the running magnetic tape MT while the guide
15 itself rotates by the running magnetic tape MT being hung across
a periphery of a roller portion 15d thereof.
[0033] In addition, as shown in FIG. 2B, the running magnetic tape
MT, which is hung across such the guide 15, contacts a periphery
thereof in a range of opening at a predetermined angle .theta. from
a center C of the rotation shaft 15c. Hereinafter the contact angle
is referred to as a wrap angle.
[0034] The wrap angle .theta. in the first guide 15a gradually
becomes small as the magnetic tape MT is sent out from the
cartridge-side reel 17 to the drive-side reel 12; the wrap angle
.theta. in the second guide 15b gradually becomes small as this
sent-out magnetic tape MT is wound on the drive-side reel 12. On
the contrary, the wrap angle .theta. in the second guide 15b
gradually becomes large as the magnetic tape MT is sent out from
the drive-side reel 12 to the cartridge-side reel 17; the wrap
angle .theta. in the first guide 15a gradually becomes large as
this sent-out magnetic tape MT is wound on the cartridge-side reel
17. In the drive A related to the embodiment the guide 15 is
arranged at positions where the wrap angle .theta., which thus
fluctuates when the magnetic tape MT reciprocates between the
cartridge-side reel 17 and the drive-side reel 12, always becomes
not more than 90 degrees. In the drive A related to the embodiment
the wrap angle .theta. is set in such the range, and thereby the
drive A is designed so that a frictional resistance of the magnetic
tape MT for the first guide 15a and the second guide 15b is
reduced, a high speed running of the magnetic tape MT can be made,
and magnetic information for the magnetic tape MT is quickly
recorded/reproduced. And in the guide 15 thus arranged a ratio of a
peripheral speed of the roller portion 15d for a running speed of
the magnetic tape M (hereinafter simply referred to as a "rotation
following ratio of the guide 15") is designed to be not more than
0.9 when the magnetic tape MT is run by a travel device.
[0035] As shown in FIG. 3, in such the guide 15 a hardening
treatment is dispensed to a surface of a base metal B and a
hardened layer H is formed on the surface. Meanwhile, although in
FIG. 3 the base metal B and the hardened layer H are clearly
discriminatingly depicted, an interface thereof is not always
clear, depending on a material of the hardened layer H.
[0036] In the hardened layer H a hardening treatment such as a
soft-nitrizing treatment, carburizing and quenching, and induction
hardening is dispensed to the base metal B or a hard film is formed
on the surface of the base metal B, for example, by a known
thin-film-forming method such as a sputtering method.
[0037] The material of the hardened layer H is not specifically
limited, and for example, are cited titan nitride (TiN), chromium
nitride (CrN), titan aluminum nitride (TiAlN), tungsten
carbide-cobalt (WC-Co), diamond-like carbon (DLC), and the like.
Meanwhile, in the hardened layer H, which is formed on the base
metal B, a polish treatment may also be dispensed so that a surface
thereof becomes a predetermined smoothness.
[0038] Next, will be described operation of the drive A related to
the embodiment, referring to FIGS. 1, 2A, 2B, and 3 as needed.
[0039] First, the magnetic tape cartridge MC is loaded in the drive
A and the first gear 11a and the second gear 11b are rotated by
drive motors not shown, and thereby the magnetic tape MT wound on
the cartridge-side reel 17 is sent out to the drive-side reel 12;
This sent-out magnetic tape MT is wound to the drive-side reel 12
and thereby runs between the cartridge-side reel 17 and the
drive-side reel 12.
[0040] Then the first guide 15a and the second guide 15b guide the
running magnetic tape MT so as to contact the magnetic head 14.
Because at this time each wrap angle .theta. of the first guide 15a
and the second guide 15b is set to become a range of not more than
90 degrees, a frictional resistance of the magnetic tape MT for the
guide 15 is reduced. As a result, because the magnetic tape MT can
be stably run at a high speed, magnetic information can be
recorded/reproduced at a high speed for the magnetic tape MT. On
the contrary, because in the first guide 15a and the second guide
15b the wrap angle .theta. is set in a range of not more than 90
degrees and a contact area of the guide 15 and the magnetic tape MT
is reduced, the rotation following ratio of the guide 15 becomes
not more than 0.9. That is, a difference occurs between a running
speed of the magnetic tape MT and a peripheral speed of the guide
15.
[0041] On the other hand, because the surface hardening treatment
is dispensed to the first guide 15a and the second guide 15b, the
flange portion 15e thereof becomes difficult to be ground. In other
words, even when the drive A is used over a long period, the
magnetic tape MT is not oscillated in the lateral directions
thereof. Accordingly, the drive A does not generate a tracking
error, not depending on recoding density of the magnetic tape MT
loaded therein being high or low, and can be used for an inspection
of the magnetic tape MT and a library over a long period.
[0042] Next, because an abrasion resistance test of a guide used in
a drive of the present invention was performed, a test result
thereof will be discussed.
[0043] The drive used in the abrasion resistance test is, as shown
in FIG. 4, designed so that the magnetic tape MT, which runs
between a pair of reels R1 and R2, is guided along a predetermined
route by guides arranged at positions #1, #2, #3, and #4. And out
of these guides, on peripheries of guides arranged at the positions
#2 and #3 a groove not shown is formed and adjusts a running speed
of the magnetic tape MT and peripheral speeds of rotating guides so
as to become nearly equal, that is, each the rotation following
ratio of the guides approximates 1. In addition, as a guide
arranged at the position #1, is used a stainless steel guide, where
a hardened layer of titan nitride (TiN) is formed on a surface
thereof.
[0044] In the abrasion resistance test, firstly setting a tension
1N and running the magnetic tape MT at 6 meters per second, measure
a rotation speed of each guide. And here make a direction of
sending the magnetic tape MT from the reel R1 to the reel R2 a
forward direction and a reverse thereof a reverse direction,
measure the rotation speed of each guide when running the magnetic
tape MT in the forward and reverse directions. The result is shown
in Table 1. Meanwhile, a rotation speed, which is described in a
column of "Start-Side Speed" in Table 1, is that of each guide when
starting to send the magnetic tape MT from the reel R1, that is,
when the magnetic tape MT is at a position X in FIG. 4. On the
other hand, a rotation speed, which is described in a column of
"Finish-Side Speed" in Table 1, is that of each guide when
finishing to send the magnetic tape MT from the reel R1, that is,
when the magnetic tape MT is at a position Y in FIG. 4.
1TABLE 1 Rotation Speed of Guide (rotation per second): The Present
Invention Forward Direction Reverse Direction Start-Side
Finish-Side Start-Side Finish-Side Guide No. Speed Speed Speed
Speed #1 78 16 21 17 #2 164 164 164 164 #3 165 164 165 164 #4 48 40
87 164
[0045] As obvious from Table 1, it turns out that the guide
arranged at the position #1 is far lower than 0.9 in the rotation
following ratio thereof.
[0046] Next, run a commercial new magnetic tape in such the drive
in the forward and reverse directions, respectively. And observe an
abrasion state of a guide arranged at the position #1 by a laser
microscope after running the magnetic tape MT by 12,000 meters.
Meanwhile, as shown in FIG. 5, a sample provided for this
observation (hereinafter referred to as a "guide sample") is
something that is cut out from the guide 15 with leaving the flange
portion 15e.
[0047] FIG. 6 is a microscope photo of a #1 guide sample when
running the magnetic tape MT.
[0048] As obvious from FIG. 6, it turns out that in the guide 15,
which is used for a magnetic tape drive of the present invention,
the flange portion 15e is not abraded away even when the guide 15
is arranged at a position where the rotation following ratio is far
lower than 0.9.
[0049] Next, as a comparison example, measure a rotation speed of
each guide for a conventional stainless steel guide same as
described above when running the magnetic tape MT. The result is
shown in Table 2.
2TABLE 2 Rotation Speed of Guide (rotation per second): Comparison
Example Forward Direction Reverse Direction Start-Side Finish-Side
Start-Side Finish-Side Guide No. Speed Speed Speed Speed #1 74 20
20 17 #2 165 165 165 165 #3 164 164 164 164 #4 66 57 93 163
[0050] As obvious from Table 2, it turns out that the guide
arranged at the position #1 is far lower than 0.9 in the rotation
following ratio thereof.
[0051] In addition, for the conventional stainless steel guide same
as described above, observe an abrasion state of a guide arranged
at the position #1 by a laser microscope. FIG. 7 is a microscope
photo of a #1 guide sample when running the magnetic tape MT.
[0052] As obvious from FIG. 7, in a flange portion used for a
conventional magnetic tape drive, it turns out that a portion
receiving the magnetic tape MT, which is running, is remarkably
abraded away.
[0053] As obvious from the abrasion resistance tests thus
described, because if a guide used for the drive of the present
invention is arranged at a position where the rotation following
ratio is lower than 0.9, the flange portion 15e (see FIG. 2A) is
not abraded away, the magnetic tape MT guided by the guide 15 is
not oscillated in the lateral directions thereof.
[0054] Thus, although the drive of the present invention is
concretely described, based on the embodiment, the invention is not
at all limited to such the embodiment and various variations are
available without departing from the spirit and scope of the
invention.
[0055] For example, although as the first guide 15a and the second
guide 15b are applied ones where a hardening treatment is dispensed
to all surfaces thereof, the present invention is not limited
thereto; for example, as shown in FIG. 8A, are available the first
guide 15a and the second guide 15b, where the hardened layer H is
formed on nothing but an inner surface I of the flange portion 15e
arising from a periphery thereof.
[0056] In addition, as shown in FIG. 8B, in the first guide 15a and
the second guide 15b the roller portion 15d and the flange portion
15e is configured of different members and the flange portion 15e,
where a surface hardening treatment is dispensed, may be joined to
the roller portion 15d.
[0057] Furthermore, although in the embodiment the drive according
to the LTO standard, that is, a single-reel cartridge drive is
exemplified, the present invention is not limited thereto and a
two-reel cartridge drive is also available.
[0058] Still furthermore, a guide used for the magnetic tape drive
of the present invention is applicable to one arranged within a
magnetic tape cartridge.
* * * * *