U.S. patent application number 10/327101 was filed with the patent office on 2003-05-08 for magnetic tape cassette.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Asano, Katsuki, Ashikawa, Teruo, Morita, Kiyoo, Moriwaki, Masayoshi, Naito, Hiroyuki, Onmori, Shozo.
Application Number | 20030086205 10/327101 |
Document ID | / |
Family ID | 18625741 |
Filed Date | 2003-05-08 |
United States Patent
Application |
20030086205 |
Kind Code |
A1 |
Ashikawa, Teruo ; et
al. |
May 8, 2003 |
Magnetic tape cassette
Abstract
In a magnetic tape cassette, a top end portion of a reel urging
plate spring for urging a tape reel is subjected to a surface
treatment to prevent from a friction. A distance between a couple
of flanges of the tape reel is selected to keep a form of the wound
magnetic tape, and to prevent the tape running from being disturbed
by the increase of a contact resistance of the tape edges to the
flanges. Additionally, positioning portions for positioning the
magnetic tape cassette relative to a magnetic tape drive device are
formed of a differential resin from the resin of the remaining part
of the cassette case. Additionally, at least one of both end faces
of each guide roller is surface treated so that the end face is not
worn through its contact with the cassette half. Further, an
information presenting section for displaying variable information
is provided at a location other than label areas of the tape
cassette.
Inventors: |
Ashikawa, Teruo; (Kanagawa,
JP) ; Naito, Hiroyuki; (Kanagawa, JP) ;
Morita, Kiyoo; (Kanagawa, JP) ; Onmori, Shozo;
(Kanagawa, JP) ; Asano, Katsuki; (Kanagawa,
JP) ; Moriwaki, Masayoshi; (Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 Pennsylvania Avenue, NW
Washington
DC
20037-3213
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
18625741 |
Appl. No.: |
10/327101 |
Filed: |
December 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10327101 |
Dec 24, 2002 |
|
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|
09833671 |
Apr 13, 2001 |
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Current U.S.
Class: |
360/132 ;
G9B/23.066; G9B/23.069; G9B/23.07; G9B/23.074 |
Current CPC
Class: |
G11B 23/0875 20130101;
G11B 23/08785 20130101; G11B 23/08728 20130101; G11B 23/08757
20130101 |
Class at
Publication: |
360/132 |
International
Class: |
G11B 023/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2000 |
JP |
P. 2000-113829 |
Claims
What is claimed is:
1. A magnetic tape cassette comprising: a case; a couple of tape
reels; a magnetic tape wound on said couple of tape reels; and at
least one reel urging plate spring for urging said tape reel to a
predetermined side within said cassette case, wherein said reel
urging plate spring comprises a contact part which contacts with
each of said tape reels, and said contact part is subjected to a
surface treatment to prevent from a friction against said tape
reels.
2. The magnetic tape cassette according to claim 1, wherein said
tape reels comprises: a reel hub to be wound with a magnetic tape
in which servo tracks for storing servo patterns and data tracks
for storing data are arranged in the tape width direction; and a
pair of upper and lower tape flanges which are provided in the form
of collars at the upper and lower ends of said reel hub and
position both side edges of the magnetic tape wound on the reel
hub, wherein a dimension between said flanges is selected to
satisfy the following requirements: 1) the writing and reading
operations of the servo patterns to and from said servo tracks of
said magnetic tape are not hindered by the disturbance of the
running of said magnetic tape when the tape edges of said magnetic
tape come in contact with said flanges and; and 2) positional
variations of the tape edges of said magnetic tape wound on said
reel hub fall within a tolerable range, thereby maintaining a good
form of the winding of said magnetic tape.
3. The magnetic tape cassette according to claim 1, wherein said
case comprises: an upper cassette half and a lower cassette half;
and positioning portions provided on said lower cassette half for
positioning said magnetic tape cassette relative to a magnetic tape
drive device, wherein said positioning portions are formed of resin
that is different from the resin of the remaining part of said
cassette case.
4. The magnetic tape cassette according to claim 1, comprising a
guide roller which have a cylindrical outer surface and are
rotatably supported in said case, wherein said case comprises an
upper cassette half and a lower cassette half, and wherein at least
one of an upper end face and a lower end face of said guide roller
is surface treated so that said end face is not worn through its
contact with said case.
5. The magnetic tape cassette according to claim 1, comprising an
information presenting section for displaying information, which is
different from a recording information on said magnetic tape
cassette, provided at a location other than label areas for labels
representing the recording information of said magnetic tape
cassette.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] 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.
[0003] 2. Description of the Related Art
[0004] 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.
[0005] 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.
[0006] 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.
[0007] To secure the dust-proof performance high enough to
withstand the outdoor condition, an outer lid 53a, an upper lid 53b
and an inner lid 53c, 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.
[0008] An opening is formed in the flat plate of the upper cassette
half 51 such that it is covered with a transparent member 58.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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 70a, the top end of the pivot 64
is urged to the lower cassette half 52.
[0013] 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).
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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 113a protruded from the inner
peripheral edge thereof is welded, by ultrasonic wave welding, to a
step 110a formed along the peripheral edge of the lower end of the
reel hub 110.
[0019] 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
[0020] 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.
[0021] 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.
[0022] 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.
[0023] In the illustrated example, as shown in FIG. 12, five servo
tracks T11 to T15 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
T21 to T24 for storing data. Those data tracks T21 to T24 are each
further divided into a plurality of narrow tracks (not shown).
[0024] The write head 121, as shown in FIG. 12, includes five gaps
G1 to G5 used for recording servo patterns, which correspond in
position to the servo tracks T11 to T15 on the magnetic tape
108.
[0025] Block patterns P1 and P2 each consisting of a plurality of
slanted linear magnetized regions are formed in each of the servo
tracks T11 to T15 as shown in FIG. 13. Servo patterns written into
the linear magnetized regions of the block patterns P1 and P2
enable one to know positions on the magnetic tape. The
writing/reading operation of data to and from the data regions is
performed on the basis of the position information.
[0026] The writing of servo patterns into servo tracks T11 to T15
is carried out when the magnetic tape is initialized in the
manufacturing process of the magnetic tape. In this case, servo
patterns are written onto the magnetic tape over its entire length
by use of a servo pattern writer, which is designed for servo
pattern writing.
[0027] In the magnetic tape writing system, the data track regions
may be managed more discretely and accurately. Accordingly, the
recording density of the magnetic tape can be remarkably increased,
when considering from a theoretical point of view.
[0028] In the servo pattern writer for initially writing servo
patterns onto the magnetic tape and the magnetic tape writer for
writing/reading data on and from the magnetic tape in the magnetic
tape writing system, if the running of the magnetic tape is
disturbed above the write head, the writing/reading operation of
the servo patterns is erroneous. As a result, the merit of high
density recording is not effectively utilized.
[0029] Therefore, some contrivance to run the magnetic tape more
accurately and stably is required in the servo pattern writer for
initially writing servo patterns onto the magnetic tape and the
magnetic tape writer for writing/reading data on and from the
magnetic tape in the magnetic tape writing system.
[0030] Improvement of an operating accuracy of the tape running
system in the magnetic tape writer and the like is not easy.
Further, such an approach frequently brings about increase of the
cost to manufacture.
[0031] The tape running stability, if realized through the
improvement of the tape running system, does not lead to the
improvement of the accuracy in the writing and reading of the servo
patterns. The reason for this is that the tape running stability
depends greatly on the dimensional accuracy or the like of the tape
reels on which the magnetic tape is wound.
[0032] In the tape reel 106, the tape edges of the both sides of
the magnetic tape 108 wound on the reel hub 110 are positioned by
the pair of the upper flanges 112 and 113. In order that a form of
the winding of the magnetic tape is kept good with less variation
of the tape edge position, a dimension WF between the flanges 112
and 113, as shown in FIG. 10, is selected to be closest to a width
dimension WT of the magnetic tape.
[0033] If the flange-to-flange dimension WF is too close to the
tape width dimension WT, the contact resistance of the tape edges
to the flanges 112 and 113 during the tape running is large,
however. As a result, the tape running is disturbed, and the
writing and reading operations of the servo patterns are frequently
erroneous. Particularly when the dimension WE between the paired
flanges 112 and 113 is uniform in value over the flange as viewed
in the radial direction, the following problem arises. In this
case, the diameter of the magnetic tape wound on the tape reel
varies, and hence the peripheral speed of the flange varies.
Consequently, the contact resistance of the tape edges to the
flanges 112 and 113 varies.
[0034] If to prevent such a disadvantage, the dimension WF between
the flanges 112 and 113 is carelessly increased, the form of the
magnetic tape 108 wound on the tape reel 106 is deformed or
disfigured.
[0035] The magnetic tape cassette is widely used for a recording
medium. There are various types of magnetic tape cassettes, such as
audio, video and computer tape cassettes. Those types of magnetic
tape cassettes may also be categorized into an analog magnetic tape
cassette and a digital magnetic tape cassette.
[0036] The basic constructions of those magnetic tape cassettes are
substantially the same; a magnetic tape, while being movable, is
held within a cassette case.
[0037] FIG. 15 is a exploded view showing a VHS video cassette as
an example of the magnetic tape cassette. A magnetic tape cassette
290 includes an upper cassette half 291 and a lower cassette half
292, each including a flat plate having walls standing erect along
its peripheral edge. A couple of tape reels 293 around which a
magnetic tape T are rotatably supported within the lower cassette
half 292. A transparent reader tape R is jointed to the end of the
magnetic tape T. The tape reels 293 are disposed on the lower
cassette half 292 such that the magnetic tape T is put between a
pair of tape guides 294, which are provided on the front end of the
lower cassette half 292.
[0038] The lower cassette half 292 and the upper cassette half 291
are combined into the cassette case. The magnetic tape T is exposed
through the front end of the cassette case. A guard panel 295 as a
cover member is rotatably mounted on the cassette case while
covering the front side of the magnetic tape T. An insertion hole
296 is formed at the center of the front end of the flat plate of
the lower cassette half 292.
[0039] When the magnetic tape cassette 290 or the like is loaded
into a magnetic tape drive unit (referred to as a "hard drive"),
such as a VTR (video tape recorder), a plurality of positioning
pins 300 provided on the hard drive are brought into engagement
with predetermined positions (reference positioning means) of the
lower cassette half 292. As a result, the magnetic tape cassette
290 is positioned in place within the hard drive.
[0040] Recently, with a change of design sense, a transparent or
semitransparent product of the skeleton type comes out in the
market. In the product, a case of an electric device or the like is
translucent so as to allow the inside of the case to be seen from
outside. To match such a design trend, there is a demand to make
translucent the cassette case made of black or blue resin, which is
used in the conventional magnetic tape cassette.
[0041] To make translucent the cassette case of the magnetic tape
cassette, the strengthening of the resin used and the maintaining
of the sliding resistance of the resin come up as the subjects to
be solved. Particularly, cut powder that is produced at the contact
portion at which the positioning member, e.g., positioning pins 300
comes in contact with the reference positioning means, attaches to
the tape, to present various problems, such as drop out. This leads
to deterioration of the product quality.
[0042] When the transparency of the resin is increased, the
mechanical strength and the wear resistance of the resin are likely
to be deteriorated because its physical property.
[0043] One possible way to solve the problem is to mix a compound,
e.g., additive, with an intention of increasing the resin strength,
in the stage of manufacturing the cassette case. This approach,
however, brings about the increase of the cost to manufacture, and
the product cost.
[0044] A magnetic tape cassette is widely used for a recording
medium. The magnetic tape cassette is classified into a public-use
magnetic tape cassette and a business-use magnetic tape cassette
when it is classified on the basis of its use. FIG. 18 is an
exploded view showing a mechanical arrangement of component parts
in a Beta cam L cassette which is a business-use magnetic tape
cassette.
[0045] As shown in FIG. 18, the Beta cam L cassette (referred to
merely as "magnetic tape cassette") 370 is made up of an upper
cassette half 371 and a lower cassette half 372, a pair of tape
reels 373 which are to be wound with a magnetic tape T and located
within the upper and lower cassette halves 371 and 372, and a lid
374 which may open and close an opening of the front ends of the
upper and lower cassette halves 371 and 372.
[0046] Guide rollers 375 and guide pins 377 made of metal, which
are wound with the magnetic tape T, are mounted on both sides of
the opening of the front end of the lower cassette half 372. The
lower cassette half 372, which is in sliding contact with the
reverse side of the magnetic tape T, is attached to the lower
cassette half 372. Reel springs 379 for urging the tape reels 373
are attached to the upper cassette half 371. The upper and lower
cassette halves 371 and 372 are coupled together by means of a
plurality of screws 380.
[0047] Of those component parts, the guide rollers 375 are made of
resin, e.g., POM, which is good in sliding property and mechanical
strength. The guide rollers 375 are cylindrical. A rotary shaft pin
376 mounted on the lower cassette half 372 is inserted into the
center hole of each of the guide rollers 375. With use of the pins,
the guide rollers 375 are rotatably supported on the lower cassette
half 372.
[0048] FIG. 19 is an enlarged view showing a structure including
the guide rollers 375 and the guide pins 377 of the lower cassette
half 372 when viewed in the direction of an arrow B in FIG. 18. In
FIG. 19, there is illustrated a state of the structure when the
magnetic tape T is put on the guide roller 375 and the guide pin
377. Between the tape reel 373 and the guide roller 375, a pad 378
is in sliding contact with the reverse side of the magnetic tape T
and urges the magnetic tape T. With this, the magnetic tape T is in
sliding contact with the circumferential outer surface of the guide
rollers 375. When the reel urging plate spring 370 is loaded to a
record/playback apparatus (not shown), and the apparatus is placed
to a playback mode or a rewind mode, the magnetic tape T passes the
outer surface of the guide rollers 375, is taken out of the
cassette case, and is wound on the magnetic head.
[0049] FIG. 20 is a cross sectional view taken line in V-V in FIG.
19. The guide rollers 375 are cylindrical and guide the magnetic
tape T with their outer surfaces. The upper end face 375a and the
lower end face 375b of the guide rollers 375 are brought into
contact with the flat plate of the upper cassette half 371 and the
flat plate of the lower cassette half 372, respectively.
[0050] When the magnetic tape T runs, the guide rollers 75 rotate
following up the running of the magnetic tape.
[0051] In the magnetic tape cassette as mentioned above, when the
guide rollers 375 rotate following the magnetic tape T, the upper
end face 375a and the lower end face 375b of the guide rollers 375
are frequently worn. When the guide rollers 375 rotate, and the
upper end face 375a and the lower end face 375b of the guide
rollers 375 come in sliding contact with the upper cassette half
371 and the lower cassette half 372, cut powder is frequently
produced at the contact portions at which the upper end face 375a
and the lower end face 375b are brought into contact with the upper
cassette half 371 and the lower cassette half 372. The cut powder
will cause serious errors, e.g., drop out.
[0052] A magnetic tape cassette is widely used for a recording
medium. The magnetic tape cassette is classified into audio, video,
and computer cassettes and others. Those magnetic tape cassettes
may be classified into a public-use magnetic tape cassette and a
business-use magnetic tape cassette when it is classified on the
basis of its use. Examples of the magnetic tape cassette of the
digital type are DAT (digital audio tape) cassette, DVC (digital
video cassette), and DDS (digital data storage) cassette. The video
magnetic tape cassette may be classified into VHS and Beta video
cassettes.
[0053] The basic constructions of those magnetic tape cassettes are
substantially the same; a tape reel with a magnetic tape wound
thereon is housed in a cassette case.
[0054] FIG. 22 is a perspective view showing a VHS magnetic tape
cassette 440, which is one form of the video magnetic tape
cassette. An external appearance of the magnetic tape cassette 440
is substantially defined by an upper cassette half 441 and a lower
cassette half 442, each being constructed such that the periphery
walls stand erect on a flat plate, and a guard panel 445 as a cover
member.
[0055] The upper cassette half 441 and the lower cassette half 442
are combined into a cassette case 440a. A couple of tape reels 450
with a magnetic tape T wound thereon are rotatably housed in the
cassette case 440a. A label area 447 is provided in the central
portion of a flat plate 41a of the upper cassette half 441. A
window 446 is located adjacent to the label area 447. The window
446 includes a transparent window member through which a user
visually checks a volume of the winding of the magnetic tape T
within the cassette case 440a. The magnetic tape is exposed through
the front end of the cassette case 440a.
[0056] The guard panel 445 is mounted on the cassette case 440a in
a hinged manner, while covering the front end of the magnetic tape
T.
[0057] As described above, various forms and types of the magnetic
tape cassettes are known. Further, the magnetic tape cassettes are
classified on the basis of the type of magnetic tape contained and
the length of the recording time of the magnetic tape. In the VHS
magnetic tape cassette, for example, four types of tape cassettes
are used which have the recording time lengths of 30, 60, 120 and
160 minutes.
[0058] In the case of the magnetic tape cassette 440, a label 460,
which describes a recording time left, the type of cassette
(recorded information) and the like, is stuck to the label 460. A
label 461 describing a title and the like (recording information)
of the contents recorded in the magnetic tape T is stuck to a label
area 448, which is located on the rear side wall 440b of the
cassette case 440a as the rear end of the magnetic tape cassette
440.
[0059] Recently, it is regarded as important to provide
advertisement or the like based on user's needs to users, as
typically found in the internet advertisement.
[0060] The inventor found the fact that useful information will
possibly be presented to the user by putting advertisement and the
like on the magnetic tape cassette.
[0061] A specific implementation of the idea is such that
information on movies are visually attached to a magnetic tape
storing a video software, which is lent out in a rental video shop,
and in this case, the former movies belong to the same genre as of
a movie stored in the magnetic tape lent out.
SUMMARY OF THE INVENTION
[0062] A main object of the present invention is to provide a
magnetic tape cassette which overcomes the above problems and has a
high commercial value.
[0063] According to a first aspect, for providing a magnetic tape
cassette which allows the cost to manufacture to be reduced, the
present invention will be described as bellows.
[0064] There is provided a magnetic tape cassette having tape
reels, which are located within a cassette case and on which a
magnetic tape is wound, and at least one reel urging plate spring
for urging the tape reel to a predetermined side within the
cassette case. In this structure, a contact part of the reel urging
plate spring at which the reel urging plate spring comes in contact
with the tape reel, is subjected to a surface treatment so as not
to create its friction against the tape reel.
[0065] The reel urging plate spring was formed by pressing an SUS
plate-like member, and a 10-points average roughness (Rz) of its
surface was within 0.6 .mu.m to 1.0 .mu.m. Those surface roughness
values naturally resulted from the pressing of the SUS plate for
spring use, and a factor of contact resistance was not taken into
account. The inventors of the present patent application discovered
the fact that its contact resistance against the pivot is reduced
if the roughness Rz at the contact part of the reel urging plate
spring is set at 0.5 .mu.m or less, and hence that even if the
pivot is made of cheap resin, the cut powder produced is remarkably
reduced in amount. A relationship between the surface roughness Rz
at the contact portion of the reel urging plate spring and the
pivot abrasion quantity are shown in Table 1.
1 Surface 0.8 0.6 0.5 0.4 0.2 roughness (Rz) Pivot abrasion 0.8 0.7
0.3 0.2 0.1 quantity (mm)
[0066] In gathering the data in the table, a pressing force of the
reel urging plate spring was 0.9N, the number of revolutions of the
tape reel was 2000 to 2200 rpm, and the diameter of the cylindrical
pivot was 1.5 mm. The tape reel was continuously and repeatedly
rotated 300 times.
[0067] Table 1 also shows that the abrasion quantity is remarkably
increased when Rz>0.5.
[0068] The surface roughness Rz of the contact part can be 0.5
.mu.m or less by subjecting the contact part to smoothing process,
hard chromium plating process or the like. The smaller the surface
roughness Rz is, the better it is, from a view point of lessening
the cut powder generation. Practically, 0.5 .mu.m is the lower
limit value when the working accuracy, cost and the like are taken
into consideration, however.
[0069] Since the magnetic tape cassette is thus constructed, the
lower flange, hub and pivot may be one-piece molded by using cheap
resin, such as ABS and PS. Accordingly, the cost of manufacture the
magnetic tape cassette is reduced.
[0070] In a second aspect, a secondary object of the invention is
to provide a tape reel in use for a magnetic tape cartridge which
1) maintains a good form of the magnetic tape wound on the tape
reel, thereby increasing the product value of the magnetic tape
cartridge in which a magnetic tape is wound on the tape reel
contained therein, 2) is free from the tape running disturbance
caused by an increase of the contact resistance of the tape edges
of the running tape to the flanges of the tape reel, 3) is free
from troubles caused by the tape running disturbance when servo
patterns are written onto and read from the magnetic tape, and 4)
realizes the improvement of the performances of writing and reading
servo patterns onto and from the magnetic tape in the magnetic tape
writer or the like.
[0071] To achieve the secondary object, the present invention
provided a tape reel in use for a magnetic tape cartridge having a
reel hub to be wound with a magnetic tape in which servo tracks for
storing servo patterns and data tracks for storing data are
arranged in the tape width direction, and a pair of upper and lower
tape flanges which are provided in the form of collars at the upper
and lower ends of the reel hub and position both side edges of the
magnetic tape wound on the reel hub. In the tape reel, a dimension
between the flanges is selected so as to satisfy the following
requirements:
[0072] 1) the writing and reading operations of the servo patterns
to and from the servo tracks of the magnetic tape are not hindered
by the disturbance of the running of the magnetic tape when the
tape edges of the magnetic tape come in contact with the flanges
and; and 2) positional variations of the tape edges of the magnetic
tape wound on the reel hub fall within a tolerable range, thereby
maintaining a good form of the winding of the magnetic tape.
[0073] A distance between a couple of flanges 135 and 136 is
selected to be a value at which a form of the winding of a magnetic
tape on a tape reel is kept good, and the tape running is not
disturbed by the increase of a contact resistance of the tape edges
to the flanges of the tape reel.
[0074] Accordingly, the form of the winding of the magnetic tape on
the tape reel is kept good, and the external appearance of the
magnetic tape cartridge in which the magnetic tape is wound on the
tape reel is improved. In this sense, the product value is
increased. Further, the tape running is not disturbed by the
increase of the contact resistance of the tape edges to the flanges
of the tape reel during the tape running. The writing and reading
of the servo patterns to and from the magnetic tape wound on the
tape reel is not hindered by the tape running disturbance. The
improvement of the performance of writing and reading the servo
patterns to and from the magnetic tape is realized at low cost in
the magnetic tape writer or the like.
[0075] In the case of the tape reel for a magnetic tape cartridge,
1) for the dimension WF between the flanges, the inside diameter of
the flange is larger than the width dimension WT of the magnetic
tape by about 0.1 mm to 0.35 mm, and the outside diameter of the
flange is larger than the width dimension WT of the magnetic tape
by 0.2 mm to 0.55 mm. 2) The inner surface of one of the flanges is
tapered so that the dimension WF between the flanges gradually
increases from the inside diameter side of the flange to the
outside diameter side.
[0076] With such a construction, even if the peripheral speed of
the flanges varies with a variation of the diameter of the winding
of the magnetic tape on the tape reel, the contact resistance of
the tape edges to the flanges less varies. Accordingly, the tape
running disturbance caused by the increase of the contact
resistance of the tape edges to the tape reel during the tape
running is more reliably prevented.
[0077] In the tape reel for the magnetic tape cartridge, the couple
of flanges 135 and 136 are preferably made of polycarbonate resin
containing glass fibers, which is excellent in mechanical strength
and heat resistance.
[0078] The servo patterns are written to the magnetic tape within
the magnetic tape cartridge before its delivery. In order to
maintain good running stability of the tape, it is preferable that
the dimension between the paired flanges of the tape reel remains
not varied for a long time, from the product delivery.
[0079] If a material making one of the flanges is different from
that making the other, the following problem arises. The flanges
will be expanded and deformed by a temperature variation during the
transportation for the product delivery and a temperature cycle in
its long time use. In this case, the expansion and deformation of
one of the flanges are different from those of the other. As a
result, the dimension between the flanges of the tape reel loses
its proper dimensional value.
[0080] If each flange is made of polycarbonate resin containing
glass fibers, which is excellent in mechanical strength and heat
resistance, it does not happen that the flanges of the tape reel
are deformed by a temperature variation during the transportation
for the product delivery and a temperature cycle in its long time
use. Further, the proper dimensional value of the dimension between
the flanges as originally set may be maintained for a long time,
from the product delivery. Accordingly, the running stability of
the magnetic tape and the form of the winding of the magnetic tape
can be kept satisfactory and good for a long time.
[0081] According to a third aspect, for providing a magnetic tape
cassette which prevents the cut powder from being produced, and is
low in the cost to manufacture, the present invention will be
described as belows.
[0082] In the present invention, there is provided a magnetic tape
cassette in which a magnetic tape is held within a cassette case
while being movable. In the magnetic tape cassette, positioning
portions, which are provided on a lower cassette half for
positioning the magnetic tape cassette relative to a magnetic tape
drive device, are formed of resin that is different from the resin
of the remaining part of the cassette case.
[0083] A strength of the positioning portions of the cassette case
is increased by forming the positioning portions of a material,
which is different from that of the remaining portion of the
cassette case. To this end, two-color molding may be used, or the
positioning portions of the cassette case may be formed separate
from the remaining portion of the cassette case.
[0084] In the thus magnetic tape cassette using the lower cassette
half, the cassette case is not damaged when the reference
positioning means are brought into contact with the positioning
members, although the cassette case is formed translucent. Further,
the magnetic tape cassette can be manufactured at low cost.
[0085] Since such a strength as not to damage the cassette case is
secured, no problems arise if the reference positioning means is
formed translucent.
[0086] In the specification, the term "translucent" of an article
means a visual state of a thing allowing one to see the inside of
the magnetic tape cassette through the article, and it may be
chromatic or achromatic.
[0087] Further, the term "strength" involves properties which does
not cause the cassette case to be cracked and not produce cut
powder, such as wearing resistance, impact resistance, viscosity
and others.
[0088] According to a fourth aspect, a secondary object of the
present invention is to provide a magnetic tape cassette which can
prevent the cut powder from being produced.
[0089] To achieve the secondary object, the present invention
provides a magnetic tape cassette in which guide rollers each
having a cylindrical outer surface are rotatably supported in a
cassette case consisting of the combination of an upper cassette
half and a lower cassette half. In this structure, at least one of
the upper end face and the lower end face of each said guide roller
is surface treated so that said end face is not worn through its
contact with said upper cassette half or lower cassette half.
[0090] The guide roller may take any form if it has a cylindrical
outer surface. When the guide roller 315 used is shaped like a
barrel, the amount of the cut powder is remarkably reduced. The
barrel shaped guide roller is configured such that the largest
diameter of the guide roller is at the center as viewed in the
axial direction and the smallest outside diameter is at both ends,
and the outside diameter of the guide roller gradually decreases
from the center to both ends as viewed in the axial direction.
[0091] Examples of the surface treatment are a smoothing treatment
and a heat treatment, e.g., ironing treatment. If the heat
treatment is used, heat treatment temperature is preferably lower
than a melting point of resin.
[0092] In the magnetic tape cassette thus constructed, no wearing
occurs at the contact portions of the upper and lower end faces of
the guide rollers with the upper and lower cassette halves. That
is, the upper and lower end faces of the guide roller are subjected
to a predetermined surface treatment. As a result, not only the
upper and lower end faces but also the upper and lower cassette
halves which are in contact with them become resistive to
abrasion.
[0093] Accordingly, the amount of the cut powder produced is
remarkably reduced.
[0094] According to a fifth aspect, a secondary object of the
present invention is to provide a magnetic tape cassette having a
display space for displaying information different from the
information recorded in the magnetic tape cassette.
[0095] To achieve the secondary object, the present invention
provides a magnetic tape cassette in which a magnetic tape, while
being movable, is held within a structure consisting of appearance
defining members and label areas are provided on the appearance
defining members. In this structure, an information presenting
section for displaying information, which is different from the
recording information on the magnetic tape cassette, is provided at
a location other than label areas of appearance defining members to
which labels representing the recording information on the magnetic
tape cassette are stuck.
[0096] With such a construction, the magnetic tape cassette may
display information, which is different from the recording
information on a magnetic tape cassette, in an information display
section which is located at a location other than label areas in
which the recording information on the magnetic tape cassette is
displayed. Accordingly, the magnetic tape cassette, which is used
for selling and lending video software items, may be effectively
used as an advertising medium by putting an advertisement in the
information display section of the cassette.
[0097] Examples of the appearance defining members are upper and
lower cassette halves, and a cover member (guard panel).
[0098] Examples of the recording information on the magnetic tape
cassette are the type of a cassette case, the type of a magnetic
tape housed in the cassette case, a recording time left of the
magnetic tape, and a title of the video software stored.
[0099] The information different from the recording information on
the magnetic tape cassette may be advertisement, rental
information, logo marks, inventory management codes, bar codes and
the like.
[0100] The advertisement is not limited to specific ones; however,
it is preferably useful for users who are at a high frequency at
which they watch the contents stored in the magnetic tape
cassette.
[0101] An example of the advertisement is an advertisement of a
movie belong to the same genre as of a movie stored in the
cassette. When an age group of users who want to watch the contents
of the cassette is specified, the advertisement may be shopping and
shop advertisements which attract those users of the age group.
Thus, the preferable advertisement has given relations to the
contents stored.
[0102] Examples of rental information are genre, film director,
cast and the like of a movie or the like stored in a rental video,
which is lent out in the video shop. Titles of rental videos which
will be lent out in near future may also be enumerated for the
advertisement.
[0103] The information different from the recording information on
the magnetic tape cassette may be attached to the appearance
defining member or members by label pasting, printing,
transferring, engraving, molding or the like.
[0104] The information may be visually presented by attaching an
information terminal, e.g., an LCD unit, to the appearance defining
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0105] FIG. 1 is a plan view showing an upper cassette half in a
first embodiment base on a first aspect of the present
invention;
[0106] FIG. 2 is a plan view showing an upper cassette half in a
second embodiment based on the first aspect of the present
invention;
[0107] FIG. 3 is an exploded view showing a conventional magnetic
tape cassette;
[0108] FIG. 4 is a diagram showing a reel urging plate spring and a
tape reel in the conventional magnetic tape cassette;
[0109] FIG. 5 is a perspective view showing a tape reel for a
magnetic tape cartridge which is an embodiment based on a second
aspect of the present invention;
[0110] FIG. 6 is an exploded view showing the tape reel shown in
FIG. 5;
[0111] FIG. 7 is a longitudinal sectional view for explaining a
method of jointing a pair of flanges of the tape reel as shown in
FIG. 5;
[0112] FIG. 8 is a longitudinal sectional view showing the tape
reel shown in FIG. 5;
[0113] FIG. 9 is a perspective view showing a conventional tape
reel used for a magnetic tape cartridge;
[0114] FIG. 10 is a longitudinal sectional view showing the tape
reel of FIG. 9;
[0115] FIG. 11 is a perspective view showing a relationship between
a magnetic tape for storing servo patterns and a write head for
writing servo patterns;
[0116] FIG. 12 is an explanatory diagram a construction of a
magnetic tape to which servo patterns are written;
[0117] FIG. 13 is an explanatory diagram showing servo patterns to
be written into the servo tracks on the magnetic tape shown in FIG.
12;
[0118] FIG. 14 is a plan view showing a lower cassette half of an
embodiment based on a third aspect of the present invention;
[0119] FIG. 15 is an exploded view showing a conventional magnetic
tape cassette;
[0120] FIGS. 16A and 16B are perspective views showing a key
portion of an embodiment based on a fourth aspect of the
invention;
[0121] FIG. 17 is a cross sectional view taken on line II-II in
FIG. 16;
[0122] FIG. 18 is an exploded view showing a conventional magnetic
tape cassette;
[0123] FIG. 19 is an enlarged view of the magnetic tape cassette
when viewed in the direction of an arrow B as shown in FIG. 18;
[0124] FIG. 20 is a cross sectional view taken on line V-V in FIG.
19;
[0125] FIG. 21 is a perspective view showing a magnetic tape
cassette which is an embodiment based on a fifth aspect of the
present invention; and
[0126] FIG. 22 is a perspective view showing a conventional
magnetic tape cassette.
DETAILED DESCRIPTION OF THE PREFERED EMBODIMENT
[0127] According to a first aspect, the preferred embodiment of the
present invention will be described with reference to the
accompanying drawings.
[0128] Components and parts already described will be designated by
like reference numerals, and description thereof will be given in
brief or omitted, for simplicity.
[0129] FIG. 1 is a plan view showing a structure on the inner side
of an upper cassette half 11 in a magnetic tape cassette (as a
business use DVC) 10, which is a first embodiment of the present
invention. A window opening is formed in a rectangular flat plate
11a of the upper cassette half 11, while being covered with a
window member 58. A pair of reel urging plate springs 20 are
provided on a flat plate 11a, while extending from the upper
corners to the center of the flat plate. Each reel urging plate
spring 20 is formed by bending a strip-like member, and includes a
base 20c and an arm 20b. The base 20c is welded onto the flat plate
11a of the upper cassette half. The arm 20b is raised from the flat
plate 11a toward the tape reel side (this side in the paper surface
of the drawing).
[0130] A top end portion 20a of the arm 20b will serve as a contact
part at which the arm is brought into contact with the tape reel. A
10-points average roughness of the surface of the top end portion
20a is set at 0.5 .mu.m or less.
[0131] In the magnetic tape cassette 10 with the upper cassette
half 11, the top end portion 20a of the reel urging plate spring 20
is smooth, and its contact resistance against the pivot of the tape
reel is small. Accordingly, there is no chance that the pivot is
damaged with the reel urging plate spring 20 and cut dust is
produced. Therefore, the pivot of the tape reel may be made of
cheap resin, so that the cost to manufacture the magnetic tape
cassette is reduced. If the pivot, and the hub and lower flange are
one-piece molded using cheap resin, further cost reduction is
realized.
[0132] FIG. 2 is a plan view showing an inner structure of an upper
cassette half 31 in a magnetic tape cassette (as a VHS video
cassette) 30, which is a second embodiment of the present
invention.
[0133] A single reel urging plate spring 40 is provided on a
rectangular flat plate 31a of the upper cassette half 31 in a state
that the plate spring longitudinally extends in the central portion
as vertically viewed. The reel urging plate spring 40 is formed
such that a strip-like member is bent such that arms 40b are raised
from both ends of a base 40c. The base 40c is welded onto the flat
plate 31a of the upper cassette half. The arms 40b are raised from
the upper cassette half 31 to the tape reel (not shown) side (this
side in the paper surface of the drawing).
[0134] Top end portions 40a of the arms 40b will serve as contact
parts at which the arms are brought into contact with the tape
reel. A 10-points average roughness of the surface of each top end
portion 40a is set at 0.5 .mu.m or less.
[0135] It should be understood that the present invention is not
limited to the above-mentioned embodiments, but may variously be
modified, altered and changed within the true spirits of the
invention.
[0136] The entire surface of the reel urging plate spring may be
smoothed, while only the top end portion of it is smoothed in the
above-mentioned embodiments.
[0137] When a portion of the reel urging plate spring other than
the top end portion thereof is brought into contact with the tape
reel (pivot), smoothing of that portion other than the top end
portion will suffice.
[0138] It is evident that the present invention may be applied to
other magnetic tape cassettes than the DVC and the VHS video
cassette.
[0139] As seen from the foregoing description, in the thus
constructed magnetic tape cassette of the invention, the lower
flange, the hub, the pivot, and the like may he one-piece molded
using cheap resin. This fact leads to the reduction of cost to
manufacture.
[0140] According to a second aspect, the preferred embodiments of a
tape reel in use for a magnetic tape cartridge according to the
present invention will be described with reference to the
accompanying drawings.
[0141] FIGS. 5 through 8 show an embodiment of a tape reel in use
for a magnetic tape cartridge according to the second aspect of the
present invention. FIG. 5 is a perspective view showing the tape
reel according to the embodiment of the present invention FIG. 6 is
an exploded view showing the tape reel shown in FIG. 5. FIG. 7 is a
longitudinal sectional view for explaining a method of jointing a
pair of flanges of the tape reel as shown in FIG. 5. FIG. 8 is a
longitudinal sectional view showing the tape reel shown in FIG.
5.
[0142] A tape reel 131 of the embodiment is used for a magnetic
tape cartridge of the one-reel type. The tape reel includes a
cylindrical reel hub 133 on which a magnetic tape 108 is wound, and
a couple of upper and lower flanges 135 and 136 which are provided
in the form of collars at the upper and lower ends of the reel hub
133 and position both side edges of the magnetic tape 108 wound on
the reel hub 133, thereby preventing the magnetic tape 108 from
being moved in the tape width direction. As shown in FIG. 12, the
magnetic tape 108 to be wound on the reel hub 133 contains servo
tracks T11 to T15 for storing servo patterns and data tracks T21 to
T24 for storing data, which are alternately arranged in the width
direction of the magnetic tape.
[0143] The flange 135, as shown in FIGS. 6 and 7, is integrally
coupled to the upper end of the reel hub 133. The lower flange 156
and the reel hub 133 are joined together in a manner that a lib
136a protruded from the inner peripheral edge thereof is welded, by
ultrasonic wave welding, to a step 133a formed along the peripheral
edge of the lower end of the reel hub 133.
[0144] The inventor of the present patent application
experimentally examined the form of the magnetic tape 108 wound on
the tape reel 131 and the running stability of the magnetic tape
108, and analyzed the experimental examination. From the
experimental analysis, the inventor found the fact that the tape
speed is affected by a thickness of the tape and the like, but more
affected by the width dimension WT of the magnetic tape and the
dimension WF between the pair of flanges 135 and 136.
[0145] As the dimension WF between the pair of flanges 135 and 136
is increased relative to the width dimension WT of the magnetic
tape, a contact resistance of the tape edges of the magnetic tape
108 to the pair of flanges 135 and 136 during the tape running
decreases. There is less chance that the tape edges come in contact
with the flanges to cause the tape running to be disturbed. On the
other hand, the capability of positioning the tape edges by the
flanges 135 and 136 decreases and its decrease is actualized. With
increase of the positional variation of the tape edges, the form of
the winding of the magnetic tape 108 is deteriorated in beauty. As
a result, the product value is degraded in light of beauty.
[0146] The characteristic of the dimension WF between the paired
flanges 135 and 136 was examined in detail. To this end, various
combinations of the values of the dimension WF between the flanges
135 and 136 were examined on two points, 1) to reduce the contact
resistance of the tape edges to the flanges 135 and 136 and 2) to
maintain a good form of the winding of the magnetic tape 108. On
the basis of the examination results, the dimension WF between the
flanges 135 and 136 is selected so as to satisfy the following
requirements: 1) the operations of writing and reading of the servo
patterns to and from the servo tracks of the magnetic tape 108 are
not hindered by the disturbance of the running of the magnetic tape
108 when the tape edges of said magnetic tape come in contact with
said flanges 135 ad 136 and; and 2) positional variations of the
tape edges of the magnetic tape 108 wound on the reel hub 133 fall
within a tolerable range, thereby maintaining a good form of the
winding of the magnetic tape 108.
[0147] The examination results showed the following facts: In the
case of the tape reel 131 for a magnetic tape cartridge of the
one-reel type, 1) for the dimension WF between the flanges 135 and
136, the inside diameter of the flange 135, 136 is larger than the
width dimension WT of the magnetic tape 108 by about 0.1 mm to 0.35
mm, and the outside diameter of the flange 135, 126 is larger than
the width dimension WT of the magnetic tape 108 by 0.2 mm to 0.55
mm; and 2) As also shown in FIG. 8, the inner surface of one of the
flanges (in the embodiment, the inner surface 135a of the upper
flange 135) is tapered so that the dimension WF between the flanges
135 and 136 gradually increases from the inside diameter side of
the flange to the outside diameter side.
[0148] A preferable material of each flange 135, 136 is
polycarbonate resin containing glass fibers, which is excellent in
mechanical strength and heat resistance.
[0149] In the tape reel 131 thus designed, the distance between the
flanges 135 and 136 of the tape reel 131 is selected to be within a
range where the form of the magnetic tape 108 wound on the tape
reel 131 is good, and the contact resistance of the tape edges to
the flanges 135 and 136 of the tape reel 131 is selected to be
within a range where the tape running is not disturbed. Therefore,
the form of the magnetic tape 108 wound on the tape reel 131 is
kept good, and the external appearance of the magnetic tape
cartridge in which the magnetic tape 108 is wound on the tape reel
131 is good, and in this sense the product valid is increased.
[0150] There is no chance that the contact resistance of the tape
edges to the flanges 135, 136 of the tape reel 131 during the tape
running and the tape running is not disturbed. In writing and
reading the servo patterns to and from the magnetic tape 108 wound
on the tape reel 131, the trouble by the tape running disturbance
does not occur. The improvement of the performance of writing and
reading the servo patterns to and from the magnetic tape 108 is
realized at low cost in the magnetic tape writer for the magnetic
tape 108.
[0151] The dimension WF between the flanges 135 and 136 is selected
to have a proper value, which is larger than that of the width
dimension WT of the magnetic tape 108. The inner surface 135a of at
least one of the flanges, i.e., the flange 135, is tapered such
that the dimension WF between the flanges 135 and 136 increases
toward the outside diameter of the flange. Even if the peripheral
speed of the flanges 135 and 136 varies with a variation of the
diameter of the winding of the magnetic tape 108 on the tape reel
131, the contact resistance of the tape edges to the flanges 135
and 136 less varies. Accordingly, the tape running disturbance
caused by the increase of the contact resistance of the tape edges
to the tape reel 131 during the tape running is more reliably
prevented.
[0152] The servo patterns are written to the magnetic tape 108
within the magnetic tape cartridge before its delivery. In order to
maintain good running stability of the tape, it is preferable that
the dimension between the paired flanges 135 and 136 of the tape
reel 131 remains not varied for a long time, from the product
delivery. If a material making one of the flanges 135 and 136 is
different from that making the other, the following problem arises.
The flanges 135 and 136 will be expanded and deformed by a
temperature variation during the transportation for the product
delivery and a temperature cycle in its long time use. In this
case, the expansion and deformation of one of the flanges are
different from those of the other. As a result, the dimension
between the flanges 135 and 136 of the tape reel 131 loses its
proper dimensional value.
[0153] If each flange 135, 136 is made of polycarbonate resin
containing glass fibers, which is excellent in mechanical strength
and heat resistance, it does not happen that the flanges 135 and
136 of the tape reel 131 are deformed by a temperature variation
during the transportation for the product delivery and a
temperature cycle in its long time use. Further, the proper
dimensional value of the dimension between the flanges 135 and 136
as originally set may be maintained for a long time, from the
product delivery. Accordingly, the running stability of the
magnetic tape 108 and the form of the winding of the magnetic tape
108 can be kept satisfactory and good for a long time.
[0154] In the above-mentioned embodiment, the inner surface of the
flange 135 is tapered such that the dimension WF between the
flanges 135 and 136 increases toward the outside diameter of the
flange. If required, the inner surface of the other flange may be
tapered in like manner.
[0155] Of course, the flange of the tape reel as above-mentioned
embodiment may be applied to the magnetic tape cassette as shown in
the first aspect of the invention. In such a combined structure,
the magnetic tape cassette having a high commercial value can be
produced and achieve the main object of the present invention.
[0156] In the tape reel in use for a magnetic tape cartridge, a
distance between a pair of flanges of a tape reel is selected to be
within a range that the form of the magnetic tape 108 wound on the
tape reel is kept good, and that the contact resistance of the tape
edges to the flanges of the tape reel during the tape running is
not in excess of such a value as to disturb the tape running.
[0157] Accordingly, the form of the winding of the magnetic tape on
the tape reel is kept good, and the external appearance of the
magnetic tape cartridge in which the magnetic tape is wound on the
tape reel is improved. In this sense, the product value is
increased. Further, the tape running is not disturbed by the
increase of the contact resistance of the tape edges to the flanges
of the tape reel during the tape running. The writing and reading
of the servo patterns to and from the magnetic tape wound on the
tape reel is not hindered by the tape running disturbance. The
improvement of the performance of writing and reading the servo
patterns to and from the magnetic tape is realized at low cost in
the magnetic tape writer or the like.
[0158] According to a third aspect, the preferred embodiment of the
present invention will be described with reference to the
accompanying drawings. In the description to follow, like or
equivalent portions are designated by like reference numerals used
in the description already given, for simplicity.
[0159] FIG. 14 is a plan view showing a lower cassette half 212 for
a magnetic tape cassette (for the VHS cassette), which is an
embodiment of the present invention. The lower cassette half 212 is
made of translucent resin.
[0160] A pair of insertion holes 219 into which reel drive shafts
of the hard drive are to be inserted are formed in a flat plate
212a of the lower cassette half 212. A light source insertion hole
296 is provided in the front end (which is confronted with the
write head when it is loaded into the hard drive) of the central
portion of the flat plate 212a as longitudinally viewed. Regions
218 consisting of vertically and horizontally extended grooves
(lines) are provided on the rear end of the flat plate 212a. The
external appearance and touch of those regions are different from
those of other regions.
[0161] Reference positioning means 220 and 221 each having a hole
are provided at two locations longitudinally spaced from each other
on the front end of the flat plate 212a of the lower cassette half
212. A hole 220a of the reference positioning means 220 is circular
as viewed from top, and a hole 221a of the other reference
positioning means 221 is elongated as viewed from top. A reference
positioning face 220b (221b) is formed on and along the opening
edge of the hole 220a (221a). The reference positioning face 220b
(221b) is formed of resin that is different from the resin of the
remaining part of the lower cassette half 212, and increased in
strength, and smoothed.
[0162] Flat reference positioning means 222 and 223 are provided at
two locations longitudinally spaced from each other on the rear end
of the flat plate 212a of the lower cassette half 212. The
reference positioning means 222 (223) is also formed of resin that
is different from the resin of the remaining part of the lower
cassette half 212, and is increased in strength and smoothed, and
serves as a reference positioning face. Both the reference
positioning means 222 and 223 are located within the regions 218
having grooves, but no grooves are formed in the reference
positioning faces.
[0163] In the lower cassette half 212, reference positioning
portions 220 to 223 are formed in and on the flat plate 212a by
two-color molding. The flat plate 212a is translucent, and the
reference positioning portions 220 to 223 are colored black.
[0164] When the magnetic tape cassette using the lower cassette
half 212 is set in the hard drive, the two positioning pins of the
hard drive are respectively inserted into holes 220a and 221a of
the reference positioning means 220 and 221, and the shoulder parts
of the positioning pins are respectively brought into contact with
the reference positioning faces 220b and 221b.
[0165] In the thus magnetic tape cassette using the lower cassette
half 212, the cassette case is not damaged when the reference
positioning means 220 to 223 are brought into contact with the
positioning members (positioning pins and the like), although the
cassette case is formed translucent. Further, the magnetic tape
cassette can be manufactured at low cost.
[0166] It should be understood that the present invention is not
limited to the embodiment mentioned above, but may variously be
modified, altered and changed within the true spirits of the
invention.
[0167] The reference positioning means may be formed translucent if
such a strength as not to damage the cassette case is secured.
[0168] If required, other predetermined locations than the lower
half cassette may be increased in strength.
[0169] The present invention may be applied to other magnetic tape
cassettes than the VHS video cassette. Examples of those other
cassettes are DVC and DAT.
[0170] Of course, the reference positioning means may be applied to
the magnetic tape cassette of the first aspect of the present
invention.
[0171] As seen from the foregoing description, in the thus magnetic
tape cassette using the lower cassette half, the cassette case is
not damaged when the reference positioning means are brought into
contact with the positioning members, and the magnetic tape
cassette can be manufactured at low cost. Further, if the cassette
case is formed translucent, no problems arise.
[0172] According to a fourth aspect, the preferred embodiment of
the present invention will be described with reference to the
accompanying drawings. In the description to follow, like or
equivalent portions are designated by like reference numerals used
in the description already given, for simplicity.
[0173] FIG. 16A is a perspective view showing a lower cassette half
312 in a magnetic tape cassette (Beta cam L cassette) which is an
embodiment of the present invention. FIG. 16B is an enlarged view
showing a structure in which a guide roller 315 and a guide pin 377
are mounted on the lower cassette half 312, the illustration being
viewed in the direction of an arrow B in FIG. 16A. The tape reel
and the upper half cassette, both not shown, may be those shown in
FIG. 18. As shown in FIGS. 16A and 16B, the guide rollers 315 and
the guide pins 377 are mounted on both sides of the opening of the
front end (is confronted with the recording head of the
record/playback device) of the lower cassette half 312.
[0174] A state of a structure in which a magnetic tape T is drawn
from a tape reel (not shown) in the direction of an arrow P, and is
taken out of the cassette case via the guide roller 315, is shown
in FIG. 16B. The magnetic tape T urged by the pad 378 runs on the
outer surface of the guide roller 315, passes between the guide
roller 315 and the guide pin 377, is taken out of the cassette
case, and put on-the magnetic head of the record/playback device
(not shown).
[0175] FIG. 17 is a cross sectional view taken on line II-II in
FIG. 16B. As shown in FIG. 17, the guide roller 315 is shaped like
a barrel, viz., its outer surface is curved such that the outside
diameter of the guide roller 315 gradually decreases from the
center to both ends as viewed in the axial direction. The guide
roller 315 is symmetrical with respect to the center thereof as
viewed in the axial direction such that the largest diameter Dmax
of it is at the center as viewed in the axial direction and the
smallest outside diameter Dmin of it is at both ends.
[0176] The guide roller 315 gives the magnetic tape T a tension, so
that its rotation well follows up the tape running. Accordingly,
when the magnetic tape T runs, it is hard to slide on the outer
surface of the guide roller 315. Accordingly, the guide roller 315
well rotates with the running of the magnetic tape T.
[0177] The upper end face 315a and the lower end face 315b of the
guide roller 315 are subjected to surface treatment, whereby those
surfaces are hard to be cut. Specifically, the upper end face 315a
and the lower end face 315b are smoothed. To this end, an ironing
process is used. The guide roller 315 is made of polyoxymethylene
(POM). The flat plates of the upper cassette half 371 and the lower
cassette half 312 include protruded support parts 371a and 312a for
supporting the guide roller 315 at the flat faces of their tops.
The upper end face 315a of the guide roller 315 is supported by the
protruded support part 371a of the upper cassette half 371. The
lower end face 315b is supported by the protruded support part 312a
of the lower cassette half 312.
[0178] A procedure of the ironing process for ironing the guide
roller 315 will be described. Two heating plates which have been
heated to a temperature within a temperature range, which is lower
than a melting point of the resin (POM), are prepared. The guide
roller 315 is sandwiched between those heating plates.
Specifically, one of the heating plates is brought into contact
with the upper end face (one of the faces) 315a, and the other
heating plate is brought into contact with the other end face (the
other face) of the guide roller 315. The thus processed upper and
lower end faces 315a and 315b are glossier than the remaining part
of the guide roller 315.
[0179] The upper and lower end faces 315a and 315b of the guide
roller 315, which have ironed, are smoothed, viz., the surface
irregularity, cut, blur and the like are removed. Accordingly,
those faces are resistive to abrasion.
[0180] In the magnetic tape cassette thus constructed, less
abrasion occurs at contact portions at which the upper and lower
end faces 315a and 315b of the guide roller 315 are in contact with
the upper and lower cassette halves 371 and 312. Specifically, the
upper and lower end faces 315a and 315b of the guide roller 315 are
ironed to be smoothed. As a result, the upper and lower end faces
315a and 315b and the upper and lower cassette halves which are in
contact with the former are resistive to abrasion.
[0181] Therefore, an amount of cut powder, which is produced at
contact portions at which the upper and lower end faces 315a and
315b of the guide roller 315 are in contact with the upper and
lower cassette halves 371 and 312, is markedly reduced.
[0182] It should be understood that the present invention is not
limited to the above-mentioned embodiment, but may variously be
modified, altered and changed within the true spirits of the
invention.
[0183] While the barrel shaped guide roller is used in the
embodiment, the guide roller may be cylindrical in shape, viz.,
uniform in diameter. Only one of the upper and lower end faces of
the guide roller may be subjected to the surface treatment.
[0184] It is evident that the present invention may be applied to
other various types of magnetic tape cassettes than the Beta cam L
cassette.
[0185] For example, the guide roller as the above-mentioned
embodiment may be applied to the magnetic tape cassette as shown in
the other aspects.
[0186] As seen from the foregoing description, the magnetic tape
cassette of the invention markedly reduces an amount of cut powder,
which is produced at contact portions at which the upper and lower
end faces of the guide roller are in contact with the upper and
lower cassette halves.
[0187] According to a fifth aspect, the preferred embodiment of the
present invention will be described with reference to the
accompanying drawings. In the description to follow, like or
equivalent portions are designated by like reference numerals used
in the description already given, for simplicity.
[0188] FIG. 21 is a perspective view showing a magnetic tape
cassette 410 which is an embodiment of the present invention.
[0189] An external appearance of the magnetic tape cassette 410 is
substantially defined by an upper cassette half 411 and a lower
cassette half 412, and a guard panel 415 as a cover member.
[0190] A pair of tape reels 450 on which a magnetic tape T is wound
are rotatably disposed within a cassette case 410a formed by
combining the upper cassette half 411 and the lower cassette half
412. The guard panel 415 is attached to the front end of the
cassette case in a hinged manner.
[0191] Label areas 447 and 448 are located on a flat plate 411a of
the upper cassette half 411 and the rear side wall 410b of the
cassette case 410a. Labels 460 and 461 describing the recording
information on the magnetic tape cassette are pasted on the label
areas 447 and 448. An information presenting section 413 is
provided in the flat plate 411a (upper part in the drawing) at a
location between the label area 447 and the guard panel 415. A
label 414 which contains information different from the recording
information on the magnetic tape cassette is pasted on the
information presenting section 413. The label 414 contains a
description of a title of a rental video which will be lent out in
near future, as the information different from the recording
information on the magnetic tape cassette.
[0192] The magnetic tape cassette 410 is able to display, for
example, the title of a rental video which will be lent out in near
future, which the title is not presented in the conventional label
areas 447 and 448.
[0193] The contents stored or the like are customarily described in
the label areas 447 and 448. The user is also accustomed to such a
visual presentation. Accordingly, if movie information not related
to the recorded contents is presented in the label areas 447 and
448, the user will be confused.
[0194] The embodiment eliminates such a user's confusion.
[0195] Further, if the label 414 is replaced with a new label
containing update rental information, update rental information is
presented to users all the time.
[0196] It should be understood that the invention is not limited to
the above-mentioned embodiment, but may variously be modified,
altered and changed with the true spirits of the invention.
[0197] In the embodiment mentioned above, the rental information is
used for the information different from the recording information
on the magnetic tape cassette.
[0198] If required, an advertisement not related to the recorded
contents may be presented in the information presenting section. If
advertisement on a supermarket located in the video shop is
presented in the information presenting section of the magnetic
tape cassette, which is frequency lent out to housewives in the
video shop, the magnetic tape cassette lent out may be used as an
effective advertising medium.
[0199] In the above-mentioned embodiment, the label containing the
information different from the recording information on the
magnetic tape cassette is pasted on the appearance defining member.
If required, the same information may be formed on the appearance
defining member by printing, transferring, engraving, molding or
the like.
[0200] According to the main object of the present invention, it is
effective that the information presenting section of this
embodiment is applied to the magnetic tape cassette as shown in the
other aspects.
[0201] As seen from the foregoing description, if the magnetic tape
cassette of the invention is used, various information may be
carried on the magnetic tape cassette in a manner that information
different from the recording information on the magnetic tape
cassette is visually presented on the appearance defining member or
members.
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