Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
2003-05-23
2004-10-12
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
Reexamination Certificate
active
06804084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic tape cassette, particularly, the invention relates to a magnetic tape cassette including an urging plate spring for urging a tape reel, to one including a tape reel in use for a magnetic tape cartridge having reel a hub to be wound with a magnetic tape, to one including a reference positioning means, to one including a guide roller for guiding a magnetic tape, and to one including a cassette case having an information presenting section.
2. Description of the Related Art
A magnetic tape cassette which effects the recording/playing-back operation with such an arrangement that a magnetic tape wound on a couple of tape reels, while allowing its run, is held within a cassette case, is generally employed in many audio and video devices.
FIG. 3
is an exploded view showing a DVC (digital video cassette), which is one example of the magnetic tape cassette. A magnetic tape cassette
50
includes an upper cassette half
51
and a lower cassette half
52
, each having a flat plate and a periphery wall. Those halves
51
and
52
are coupled together a plurality of screws
54
. A couple of tape reels
60
, each consisting of an upper flange and a lower flange, which are welded together, are rotatably supported within the lower cassette half
52
in a state that a magnetic tape
57
is wound on those tape reels.
Tape guides
55
are respectively provided on both sides of an opening
56
of the front side (this side in the figure) of the lower cassette half
52
. The tape guides
55
guide the magnetic tape
57
, which is fed from one of the tape reels
60
and taken up by the other, and moves the magnetic tape
57
through a predetermined position in the opening
56
.
To secure the dust-proof performance high enough to withstand the outdoor condition, an outer lid
53
a
, an upper lid
53
b
and an inner lid
53
c
, which are lid members for covering the magnetic tape
57
tensioned between the couple of the tape guides
55
of the lower cassette half
52
, are mounted on the front end of the upper cassette half
51
in a state that those may be opened and closed.
An opening is formed in the flat plate of the upper cassette half
51
such that it is covered with a transparent member
58
.
Reel urging plate springs
70
are provided on a flat plate of the upper cassette half
51
, while being respectively associated with the tape reels
60
. The reel urging plate springs
70
are fastened to the upper cassette half
51
, and urge the associated tape reels
60
toward the lower cassette half
52
. As a result, the tape reels
60
are not shaky within the upper and lower cassette halves
51
and
52
.
FIG. 4
is a diagram showing how the reel urging plate springs
70
urge the tape reels
60
. Each the tape reel
60
includes a cylindrical hub
61
on which a magnetic tape is to be wound, a disc-like upper flange
62
provided on one end (the upper end in the figure) of the hub
61
, and a disc-like lower flange
63
provided on the other end of the hub
61
. A pivot
64
is provided at the center of the upper surface of the hub
61
. The hub
61
serves as a contact part which comes in contact with the reel urging plate spring
70
. In this instance, the hub
61
, the lower flange
63
and the pivot
64
are formed in a one-piece construction.
A welding boss
65
is provided around the pivot
64
. The upper flange
62
is welded on the upper surface of the hub
61
in such a manner that a welding horn (not shown) is brought into contact with the upper surface of the hub
61
in a state that the pivot
64
and the boss
65
are fit into the pivot and boss holes of the associated upper flange
62
.
The top end of the pivot
64
is protruded above the upper surface of the upper flange
62
. The reel urging plate spring
70
is fastened at its base to the flat plate of the upper cassette half
51
(see FIG.
3
), and with its tip
70
a
, the top end of the pivot
64
is urged to the lower cassette half
52
.
The lower flange
63
, the hub
61
and the pivot
64
are made of resin of high rub resistance, e.g., polyoxymethylene (POM) in order to be durable when it is brought into contact with the drive shaft of a recording/playing-back device (not shown), the lower cassette half
52
(see
FIG. 3
) when the magnetic tape cassette drops, and the reel urging plate spring
70
The upper flange
62
is made of resin, which is cheaper in cost and inferior in rub resistance than POM. Example of such resin are acrylonitrile-butadinene-styrene (ABS) and polystyrene (PS).
If the lower flange
63
, the hub
61
and the pivot
64
of each tape reel
60
are made of cheap resin with an intention of cost reduction of the magnetic tape cassette, the following problems arise.
Firstly, the tip of the pivot
64
made of cheap resin will be worn away through its contact with the reel urging plate spring
70
to produce cut powder since the rub resistance of the cheap resin is inferior to POM or the like. The cut powder thus produced will cause drop-out trouble and hinder smooth rotation of the tape reels
60
.
One possible solution to this problem is that the lower flange
63
and the hub
61
are one-piece molded using cheap resin, and a hub
61
made of POM or the like is assembled into the hub
61
. This approach, however, does not lead to the cost reduction of the magnetic tape cassette. Further, in a magnetic tape cassette, such as DVD or 8 mm cassette, in which the diameter of the hub
61
is small, it is difficult to use a separate pivot in manufacturing the tape cassette.
Next, a tape reel
106
of the magnetic tape cartridge, as shown in
FIG. 9
, includes a cylindrical reel hub
110
on which a magnetic tape
108
is wound, and a couple of upper and lower flanges
112
and
113
which are provided in the form of collars at the upper and lower ends of the reel hub
110
and position both side edges of the magnetic tape
108
wound on the reel hub
110
.
In the tape reel
106
discussed here, as shown in
FIG. 10
, the upper flange
112
is integrally coupled to the upper end of the reel hub
110
. The lower flange
113
and the reel hub
110
are joined together in a manner that a lib
113
a
protruded from the inner peripheral edge thereof is welded, by ultrasonic wave welding, to a step
110
a
formed along the peripheral edge of the lower end of the reel hub
110
.
A new technique for increasing a recording density of a magnetic tape, which is contained in the magnetic tape cartridge, is disclosed in Japanese Patent Unexamined Publication No. Hei. 8-30932(JP-A-8-30932), for example. The technique is a magnetic tape writing system in which the operations of reading data from and writing data onto a magnetic tape are controlled in accordance with servo patterns written in the magnetic tape in advance
In the magnetic tape writing system, servo tracks for storing servo patterns indicative of tape position information and data tracks for storing data are arranged in the tape width direction. The reading/writing operations by the magnetic head is controlled in accordance with servo patterns written in the magnetic tape.
FIGS. 11 and 12
show constructions including a write head and its vicinities in a servo pattern writer, which writes or records servo patterns onto the magnetic tape used in the magnetic tape writing system.
Guide posts
123
and
124
for guiding the magnetic tape
108
to a write head
121
, as shown in
FIG. 11
, are provided on both sides of the write head
121
for recording servo patterns. An arrow X in
FIGS. 11 and 13
indicates a traveling direction of the magnetic tape
108
.
In the illustrated example, as shown in
FIG. 12
, five servo tracks T
11
to T
15
for storing servo patterns are arranged at fixed spatial intervals in the tape width direction. Four regions each located between the adjacent servo tracks are used as data tracks T
21
to T
24
for storing data. Those data tracks T
21
to T
24
are each further divided into a plurality of narrow tracks (not shown).
The write head
Asano Katsuki
Ashikawa Teruo
Morita Kiyoo
Moriwaki Masayoshi
Naito Hiroyuki
Fuji Photo Film Co. , Ltd.
Klimowicz William
Sughrue & Mion, PLLC
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