Recording medium device provided with erroneous recording prevention mechanism

A recording medium device adapted so that a recording medium on which information signals are recorded is accommodated. This recording medium device comprises a cartridge body within which the recording medium on which information signals are recorded is accommodated, and an erroneous recording prevention member including a portion of detection detected by a detection mechanism of the recording/reproduction unit side, and attached to the cartridge body so that it can be moved within the range between a first position where the portion of detection is detected by the detection mechanism and a second position where it is not detected by the detection mechanism. This erroneous recording prevention member is attached to the cartridge body so that the portion of detection can be moved within the range between the first position and the second position by holding or clamping a portion of the cartridge body by a holding portion provided at the base end portion side where the portion of detection is provided and inserting an insertion portion provided at the front end side of the holding portion from the external side toward the internal side of the cartridge body.

FIELD OF THE INVENTION 
This invention relates to a recording medium device adapted so that a 
recording medium on which information signals are recorded such as a 
magnetic tape or an optical disc, etc. is accommodated within the 
cartridge body, and more particularly to a recording medium device 
provided with an erroneous recording prevention mechanism for preventing 
erasure of previously recorded information signals due to erroneous 
overwrite recording of information signals onto a recording medium 
accommodated within the cartridge body. 
BACKGROUND OF THE INVENTION 
Hitherto, in an information processing equipment for processing information 
signals such as computer, etc., an external storage (memory) unit is used 
for recording and retaining information signals which have been processed 
by this equipment, or recording information signals which are to be 
processed by the information processing equipment. For such an external 
storage unit, a recording/reproduction apparatus (unit) using a recording 
medium device adapted so that a recording medium on which information 
signals are recorded such as a magnetic tape or an optical disc, etc. is 
accommodated within the cartridge body. 
A recording medium device in the form of a tape cartridge used in such a 
recording/reproduction unit is shown in FIG. 1. This tape cartridge 500 
includes a cartridge body 501, a substantially rectangular cover member 
502 formed by molding transparent synthetic resin material, e.g., 
polycarbonate resin, etc. and a base plate 503 joined to the cover member 
502 by screws, etc. with the base plate 503 formed by a metal plate such 
as an aluminum plate, etc. Within the cartridge body 501, a pair of tape 
reels (not shown) are rotatably accommodated. Thus, a magnetic tape 504 
withdrawn from one tape reel passes through the cartridge body 501 along 
the front portion 501a thereof, and is wound onto the other tape reel. 
At one side of the front portion 501a of the tape cartridge 500, a cover 
body 505 is rotatably attached for opening/closing an opening portion for 
receiving a magnetic head which relatively comes into slidable contact 
with the magnetic tape 504 to perform recording and/or reproduction of 
information signals. Moreover, substantially at the central portion of the 
front portion 501a, an opening portion 507 is provided which allows the 
outer circumferential portion of a belt drive roller 506 for traveling the 
magnetic tape 504 at a constant velocity to extend outwardly therefrom. In 
addition, within the tape cartridge 500, an endless belt (not shown) for 
driving the tape reels is disposed. This endless belt is moved when the 
belt drive roller 506 is rotated. 
In operation, when this tape cartridge 500 is loaded into the 
recording/reproducing unit as an auxiliary memory unit, the cover body 505 
is opened. As a result, the magnetic head of the recording/reproduction 
unit side is received through the opening portion for 
recording/reproduction to lightly touch the signal recording surface of 
the magnetic tape 504. Moreover, a drive roller of the 
recording/reproduction unit side is inserted into the cartridge body 501 
through the drive opening portion 507 provided at the front side of the 
cartridge body 501 to come into contact with the belt drive roller 506. 
Then, when the drive roller of the recording/reproduction unit is 
rotationally driven, the tape reels are rotated through the belt drive 
roller 506 so that the magnetic tape 504 moves at the contact velocity, 
whereby recording and/or reproduction of information signals are carried 
out by the magnetic head which is slidably in contact with the magnetic 
tape 504. 
Meanwhile, this tape cartridge 500 includes an erroneous recording 
prevention mechanism 508 for preventing erasure of previously recorded 
information signals due to erroneous overwrite recording of information 
signals performed on the magnetic tape 504. 
This erroneous recording prevention mechanism 508 includes, as shown in 
FIG. 2, an erroneous recording detection hole 509 provided at the cover 
member 502 and positioned at one side of the front portion 501a of the 
cartridge body 501, and an erroneous recording prevention member 510 
attached to the cover member 502 so that it can be moved within the range 
between a first position where it opens the erroneous recording detection 
hole 509 and a second position where it closes the erroneous recording 
detection hole 509. 
As shown in FIG. 2, the erroneous recording detection hole 509 is provided 
at the front portion 501a of the cartridge body 501 in a manner to 
correspond to a recessed portion 511 for guiding movement thereof 
extending over a main surface portion 501b of the cartridge body 501 where 
the erroneous recording prevention member 510 is disposed so that it can 
be moved. 
Further, the erroneous recording prevention member 510 disposed within the 
recessed portion 511 includes, as shown in FIG. 2, a portion of detection 
(detected portion when viewed from the recording medium device) 513 
opposite to the erroneous recording prevention hole 509, a holding portion 
521 including a movement guide piece 512 and a supporting piece 514 
extended in parallel in a manner opposite to each other from the portion 
of detection 513, and an engagement projection 515 projecting (hereinafter 
simply referred to as "projected" as occasion may demand) from the surface 
side opposite to the supporting piece 514 of the front end side of the 
movement guide piece 512. In this case, the portion of the detection 
member 513 is formed so as to have a size (dimensions) sufficient to close 
the erroneous recording detection hole 509. 
The erroneous recording prevention member 510 as described above is 
attached to the cartridge body 501 as shown in FIG. 3 in a manner to 
extend the movement guide piece 512 formed of the holding portion 521 
toward a main surface portion 501b side of the recessed portion 511, to 
insert the supporting piece 514 into the erroneous recording detection 
hole 509, and to clamp or hold a bottom surface portion 516 of the 
recessed portion 511 by the movement guide piece 512 and the supporting 
piece 514. Moreover, the erroneous recording prevention member 510 is 
formed so that when it is attached to the cartridge body 501, an 
engagement projection 515 projecting from the front end side of the 
movement guide piece 512 is engaged with an engagement groove 517 formed 
in the bottom surface portion 516 of the recessed portion 511. Further, 
the erroneous recording prevention member 510 is caused to undergo 
movement operation in the direction indicated by arrow A and in the 
direction indicated by arrow B in FIGS. 1 and 4 within the range between 
the first position where the erroneous recording detection hole 509 is 
opened as shown in FIGS. 4 and 5 and the second position where the 
erroneous recording detection hole 509 is closed, which is indicated by 
single dotted lines in FIG. 4 while allowing the engagement projection 515 
to be guided by the engagement groove 517. The erroneous recording 
prevention member 510 is adapted so that when it is moved to the first or 
second positions, a side edge of the detection member 513 is held by a 
holding projection 518 projected from the central portion of a side edge 
509c of the lower side in the figure of the erroneous recording detection 
hole 509 of the cover member 502, whereby the erroneous recording 
prevention member 510 is held at the position where it is moved to the 
first or the second position. 
Further, the erroneous recording prevention member 510 is caused to undergo 
movement operation in the direction indicated by arrow A in FIG. 4 within 
the recessed portion 511 as a movement guide. Thus, when the erroneous 
recording prevention member 510 is placed wherein a portion of the 
detection member 513 is moved to the second position where it closes the 
erroneous recording detection hole 509 as indicated by single dotted lines 
in FIG. 4, the portion of the detection member 513 is detected by the 
erroneous recording detection mechanism provided at the 
recording/reproducing unit side into which the tape cartridge 500 is 
loaded. Namely, when the tape cartridge 500 is loaded into the 
recording/reproduction unit, the detection element of the erroneous 
recording detection mechanism is pressed by the detection member portion. 
When the portion of the detection member 513 is detected by the erroneous 
recording detection mechanism of the recording/reproduction unit, the 
recording/reproduction unit is placed in its recording operation mode 
where recording of information signals can be performed with respect to 
the magnetic tape 504. 
Moreover, the erroneous recording prevention member 510 is caused to 
undergo movement operation in the direction indicated by arrow B in FIG. 4 
within the recessed portion 511 as a movement guide. When the portion of 
the detection member 513 indicated by solid line in FIG. 4 is moved to the 
first position, the erroneous recording detection hole 509 is opened. 
Thus, the portion of the detection member 513 is not detected by the 
detection element of the erroneous recording detection mechanism provided 
at the recording/reproduction unit side. At this time, the erroneous 
recording detection mechanism is placed in an inoperative state where the 
detection element is projected into the erroneous recording prevention 
hole 509 to stop the recording operation mode, such that recording of 
information signals onto the magnetic tape 504 is impossible. Namely, when 
the erroneous recording prevention member 510 is moved to the first 
position, the tape cartridge 500 is placed such that re-recording of 
information signals onto the magnetic tape 504 is impossible. Thus, 
erasing of information signals recorded on the magnetic tape 504 is 
prevented. 
In the above-described tape cartridge 500, the erroneous recording 
prevention member 510 is attached so that it can be moved within the 
recessed portion 511 so that the bottom surface portion 516 of the 
recessed portion 511 of the cartridge body 501 is held by the holding 
portion 521 formed by the movement guide piece 512 and the supporting 
piece 514 in such a manner to put it therebetween to allow the engagement 
projection 515 to be relatively engaged with the engagement groove 517. 
Namely, the erroneous recording prevention member 510 is attached in such 
a manner that it moves along the surface of the external side of the 
cartridge body 501 such that it holds a portion of the cartridge body 501 
by the holding portion 521 provided at the base end portion side. 
Moreover, since the erroneous recording prevention member 510 is formed so 
as to have a size (dimensions) to open or close the erroneous recording 
detection hole 509 provided at the cartridge body 501 at the position 
where the erroneous recording prevention member 510 does not impede 
movement of the magnetic tape 504 within the cartridge body 501, 
limitations in the shape and/or size thereof exist, and it is difficult to 
stiffly or rigidly attach the erroneous recording prevention member 510 to 
the cover member 502. For this reason, when a large force is applied to 
the tape cartridge 500, the erroneous recording prevention member easily 
slips off from the cover member 502. 
Further, in such cases that, e.g., writing appliance or nail, etc. is 
caught by the movement guide piece 512 or the portion of the detection 
member 513, the erroneous recording prevention member 510 may be easily 
deformed so that it slips off from the cover member 502. In addition, when 
a nail or pin, etc. is inserted into the portion between the erroneous 
recording prevention member 510 and the recessed portion 511 for movement 
guide to break it, the erroneous recording prevention member 510 can be 
detached from the cover member 502 with ease. 
When the erroneous recording prevention member 510 is inadvertently moved 
as described above, a possibility exists that the tape cartridge 500 may 
be set to the recording unable state from the recordable state of 
information signals, or to the recordable state from the recording unable 
state, so recording of a desired information signal becomes impossible, or 
overwrite recording of information signals may be performed so that 
information signals previously recorded on the magnetic tape 504 are 
erroneously erased. In addition, when the erroneous recording prevention 
member 510 slips off from the cartridge body 501, the erroneous recording 
prevention hole 509 remains opened. Thus, it becomes impossible to record 
a desired information signal with respect to the magnetic tape 504. 
Moreover, in the tape cartridge 500 used as a recording medium of the 
recording/reproduction unit used in the auxiliary unit for computer, the 
recording capacity of information signals is larger and the tape cartridge 
500 is compact and light in weight. The large recording capacity is 
attained, e.g., by improving the composition or material, etc. of the 
magnetic medium used for the magnetic tape 504 and by increasing the 
number of windings of the magnetic tape 104 wound on the tape reel. 
However, in the tape cartridge 500, when the number of windings of the 
magnetic tape 504 is increased, the outside diameter of the tape reel in 
turn increases. As a result, it becomes difficult to hold or maintain the 
clearances between the tape reels and respective members or respective 
portions disposed within the cartridge body 501. 
Further, within the tape cartridge 500 adapted so that the magnetic tape is 
accommodated therewithin, plural guide pins or guide rollers, etc. forming 
the traveling path of the magnetic tape 504 are provided on a base plate 
503. However, where the tape reel has a large diameter as described above, 
such a countermeasure to change the positions where these guide pins or 
guide rollers are disposed is required. In the tape cartridge 500, the 
magnetic tape 504 is traveled along the front portion 501a as described 
above, and the erroneous recording prevention mechanism 508 is disposed at 
the front portion 501a side. 
In the case where such a countermeasure to positionally shift (change) 
guide pins or guide rollers toward the lateral side of the cartridge body 
501, or the like is necessary in the tape cartridge 500 of this kind, 
these guide pins, etc. might be positioned in the movement area of the 
erroneous recording prevention member 510. As a result, it becomes 
impossible to positionally shift (change) the erroneous recording 
prevention member 510 to a desired position. 
Moreover, the erroneous recording prevention mechanism is provided not only 
at the above-described tape cartridge 500 within which the magnetic tape 
504 is accommodated, but also at the disc cartridge adapted so that a 
disc-shaped recording medium such as optical disc or magnetic disc, etc. 
is accommodated within the cartridge body formed by butt-joining 
rectangular pair of upper and lower halves. The erroneous recording 
prevention mechanism provided at this disc cartridge is also formed of an 
erroneous recording detection hole provided at the cartridge body and an 
erroneous recording prevention member caused to undergo movement operation 
within the range between a first position and a second position when 
opening/closing this detection hole. The erroneous recording prevention 
member attached at this disc cartridge is assembled (attached) to the 
cartridge body in the state where the entirety is positioned between the 
upper half and the lower half in a manner such that the operation portion 
for allowing the erroneous recording prevention member to undergo movement 
operation is faced externally from the movement operation hole provided at 
the cartridge body. In the disc cartridge of this kind, since assembling 
between the upper half and the lower half is performed at the final 
assembly step, there is the problem that the erroneous recording 
prevention member assembled or attached in advance at the lower half side 
may slip off during the assembling step. 
OBJECTS AND SUMMARY OF THE INVENTION 
An object of this invention is to provide a recording medium device capable 
of easily attaching the erroneous recording prevention member with respect 
to the cartridge body, and capable of preventing the erroneous recording 
prevention member attached to the cartridge body from easily slipping off 
from the cartridge body. 
Another object of this invention is to provide a recording medium device 
adapted for securely holding the erroneous recording prevention member at 
a position where the erroneous recording detection hole is opened and a 
position where it is closed, thus making it possible to securely set the 
condition where information signals are permitted to be recorded onto the 
recording medium and the condition where information signals are unable to 
be recorded onto the recording medium. 
A recording medium device according to this invention proposed in order to 
attain objects as described above comprises a cartridge body accommodating 
a recording medium on which information signals are recorded, and an 
erroneous recording prevention member including a portion of a detection 
member (detected portion when viewed from the recording medium device) 
detected by a detection mechanism of the recording/reproduction unit side, 
and attached to the cartridge body so that it can be moved between a first 
position where the portion of detection is detected by the detection 
mechanism and a second position where it is not detected by the detection 
mechanism. This erroneous recording prevention member is attached to the 
cartridge body so that a portion of the detection member can be moved 
between the first position and the second position by holding or clamping 
a portion of the cartridge body by a holding portion provided at the base 
end portion side where the portion of the detection member is provided and 
inserting an insertion portion provided at the front end side of the 
holding portion from the external side toward the internal side of the 
cartridge body. 
Since the erroneous recording prevention member is attached so that a 
portion of the cartridge body is held by the holding portion from the 
external side and the insertion portion provided at the holding portion 
front end side is inserted toward the interior of the cartridge body, the 
erroneous recording prevention member is prevented from easily slipping 
off from the cartridge body. Thus, the erroneous recording prevention 
member is stably moved between the first position and the second position. 
Moreover, since the erroneous recording prevention member is attached to 
the cartridge body so that the insertion portion provided at the front end 
side of the holding portion is inserted into the cartridge body comes into 
pressure contact with the inner surface side of the cartridge body and 
provides a repulsive force (elasticity) thereto, the erroneous recording 
prevention member is attached to the cartridge body in the state where it 
is elastically held with respect to the cartridge body by the holding 
portion and the insertion portion. Thus, a firm or strong attachment state 
is achieved. 
Further, the erroneous recording prevention member is attached to the 
cartridge body so that it is moved parallel to the front portion of the 
cartridge body, or within the range between a first position where the 
portion of detection is moved to the front portion side of the cartridge 
body and a second position where the portion of the detection member is 
moved toward the interior of the cartridge body. 
Furthermore, the erroneous recording prevention member is attached so that 
it is rotated between a first position where the portion of the detection 
member is detected by the detection mechanism of the 
recording/reproduction unit side and a second position where it is not 
detected by the detection mechanism. 
In addition, at the cartridge body, an erroneous recording prevention hole 
for permitting the detection element of the detection mechanism of the 
recording/reproduction unit side to be projected thereinto is provided. 
This erroneous recording prevention hole is opened or closed by the 
portion of the detection member of the erroneous recording prevention 
member moved within the range between the first position and the second 
position.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS OF THE INVENTION 
Further practical embodiments of a recording medium device according to 
this invention will now be described below with reference to the attached 
drawings. 
In the respective embodiments disclosed below, the present invention 
relates to a tape cartridge using a magnetic tape as a recording medium on 
which information signals are recorded. Specifically, the tape cartridges 
of the respective embodiments disclosed herein are used in a 
recording/reproduction apparatus (unit) of an information processing 
equipment such as computer, etc, and are used for recording information 
signals such as data, etc. recorded at the information recording section 
of the information processing equipment, or information signals such as 
data, etc. delivered to the information processing equipment. 
The first preferred embodiment of the tape cartridge to which this 
invention is applied will be first described. 
This tape cartridge 1 includes, as shown in FIGS. 6 and 7, a cartridge body 
2 substantially rectangular in shape including a cover member 3 and a base 
plate 4 which are butt-joined to each other. The cover member 3 is formed 
by a transparent synthetic resin material such as polycarbonate resin, 
etc. as a substantially rectangular box-shaped member in which the lower 
portion thereof is opened. The base plate 4 joined (connected) to the 
opened lower surface side of the cover member 2 is formed by punching a 
metal plate in the form of a thin plate of aluminum or aluminum alloy, 
etc. The cover member 3 and the base plate 4 are integrally assembled by 
set screws 5 (see FIG. 7) fastened into studs (not shown) projecting from 
the cover member 3 and studs 6 projecting from the inner surface of the 
cover member 3 relatively engaged with or into engagement holes 6a 
provided at the base plate 4 as shown in FIG. 8. 
At both side portions of the front portion 2a side of the cartridge body 2, 
as shown in FIG. 6, engagement grooves 2b, 2c are provided which are 
engaged with projected portions for positioning the cartridge loading 
portion of the recording/reproduction unit side into which the tape 
cartridge 1 is loaded. These engagement grooves 2b, 2c respectively 
project from both sides of the cover member 3 and the side edge portions 
of the base plate 4. 
Moreover, at one side of the front portion 2a of the cartridge body 2, as 
shown in FIG. 6, an opening portion 7 is provided for 
recording/reproduction in a recess form into which the magnetic head of 
the recording/reproduction unit is inserted into which the tape cartridge 
1 is loaded. As shown in FIG. 7, this opening portion 7 is formed by a 
recess shaped portion 7a formed at the front side of the cover member 3 
and a cut recessed portion 7b formed in a portion of the front end side of 
the base plate 4. As shown in FIG. 8, a magnetic tape 12 wound between a 
pair of tape reels 13a, 13b faces to the opening portion 7 for 
recording/reproduction. This magnetic tape 12 is drawn out into the 
opening portion 7 through tape drawing holes formed at the both sides of 
the opening portion 7, and passes along the bottom surface of the opening 
portion 7. Moreover, the opening portion 7 for recording/reproduction is 
formed so as to have a size (dimensions) such that the magnetic head of 
the recording/reproducing unit into which the tape cartridge 1 is loaded 
is permitted to be sufficiently inserted thereinto, and is opened or 
closed by a cover body 8 attached at the cartridge body 2. This cover body 
8 is formed so as to have a shape formed substantially along the same 
plane surface as the front surface portion 2a of the cartridge body 2 as 
shown in FIG. 6 when the opening portion 7 is closed. In this position, 
the base end portion side thereof is rotatably supported on a support 
shaft 9 vertically provided at one comer portion of the front side of the 
base plate 4. Further, the cover body 8 is biased in a direction to close 
the opening portion 7 for recording/reproduction by a torsion spring 10 
wound on the support shaft 9. In addition, the cover body 8 is adapted so 
that one end portion 8a of the base end portion side thereof is projected 
into an engagement recessed portion 2b of the cartridge body 2. 
Further, at the central portion of the base plate 4, as shown in FIGS. 7 
and 8, a pair of reel support shafts 1a, 1b are vertically provided in 
parallel in the length direction of the base plate 4. A pair of tape reels 
13a, 13b on which the magnetic tape 12 is wound are respectively rotatably 
supported on these tape reels 13a, 13b. Each of these tape reels 13a, 13b 
includes a hub around which the magnetic tape 12 is wound on the outer 
circumferential portion thereof, a lower flange formed integrally with the 
hub, and an upper flange assembled or attached with respect to the hub 
opposite to the lower flange. The transparent leader tapes of a 
predetermined length of the magnetic tape 12 are respectively connected to 
the both end portions thereof, wherein these leader tapes are respectively 
fixed on the hubs by clamp members. 
Furthermore, at the base plate 4, a pair of guide rollers 14a, 14b are 
positioned at both corner portions of the front portion thereof. These 
guide rollers 14a, 14b are supported by support shafts vertically provided 
on the base plate 4. Flanges for supporting the both side ends of the 
magnetic tape 12 project from upper and lower end portions of the guide 
rollers 14a, 14b. In addition, at the base portion 4, tape guides 15a, 15b 
are vertically positioned at the extended portions of the cut recessed 
portion 7b forming the opening portion 7 for recording/reproduction and at 
both sides of belt drive roller 17 which will be described later. 
Accordingly, in the above-mentioned tape cartridge 1, as shown in FIG. 8, 
the magnetic tape 12 withdrawn from one tape reel 13a is guided toward the 
outer circumferential portion of one guide roller 14a and is guided along 
the front portion 2a of the cartridge body 2 by the guide roller 14a. 
Further, the magnetic tape 12 passes along the front portion 2a of the 
cartridge body 2, and is guided toward the outer circumferential portion 
of the other guide roller 14b traversing the opening portion 7 for 
recording/reproduction which is supported between a pair of tape guides 
15a, 15b. The magnetic tape 12 is guided toward the interior by the guide 
roller 14b, and is wound onto the other tape reel 13b. 
Moreover, a tape drive mechanism for allowing the magnetic tape 12 to be 
moved along the above-described traveling path is provided within the tape 
cartridge 1. This tape drive mechanism includes, as shown in FIG. 7, an 
endless drive belt 16, a belt drive roller 17, and a pair of belt guide 
rollers 18a, 18b. The belt drive roller 17 is rotatably attached on a 
support shaft 19 vertically positioned substantially at the central 
portion in the length direction of the front side of the base plate 4. 
This belt drive roller 17 is formed by elastic material having an abrasion 
resistance. At the upper side portion of the outer circumferential portion 
on which the endless drive belt 16 is laid or positioned, a drive flange 
portion of relatively large diameter adapted to be in rolling contact with 
the drive roller of the recording/reproduction unit to receive transmitted 
rotational force is integrally provided. 
As shown in FIG. 7, the belt guide rollers 18a, 18b are respectively 
positioned at both corner portions of the rear side of the base plate 4. 
These belt guide rollers 18a, 18b are respectively rotatably attached on 
support shafts 18c, 18d vertically provided on the base plate 4. In this 
embodiment, the belt guide rollers 18a, 18b are formed by elastic material 
such as synthetic rubber, etc. so as to attain a substantially tubular 
shape. 
As shown in FIG. 8, the endless drive belt 16 is laid or positioned on the 
outer circumference of the small diameter portion of the belt drive roller 
17 in contact with the outermost circumferential portion of the magnetic 
tape 12 wound on one tape reel 13a from one belt guide roller 18a by a 
predetermined tension. Moreover, the endless drive belt 16 is guided 
toward the other belt guide roller 18b in the state in contact with the 
outermost circumferential portion of the magnetic tape 12 wound on the 
other tape reel 13b from the belt drive roller 17 by a predetermined 
tension. Accordingly, the endless drive belt 16 undergoes endless 
traveling along the substantially T-shaped traveling path within the 
cartridge body 2 as shown in FIG. 7. 
Further, an end portion detection mechanism for detecting the initial end 
or the terminating end of the magnetic tape 12 is provided within the tape 
cartridge 1. As shown in FIG. 8, this end portion detection mechanism 
includes a reflection member 20 assembled within an attachment hole 
provided parallel to the front edge of the base plate 4 and positioned in 
the vicinity of one guide roller 14b of the base plate 4. In this 
embodiment , the attachment hole is formed by the attachment portion of 
the reflection member 20, and creates an incident hole for detection light 
emitted from the light emitting element of the recording/reproduction unit 
side. The reflection member 20 is formed by, for example, a transparent 
polycarbonate resin having light transmissivity so that the 
cross-sectional shape is generally triangular, wherein a reflection 
material, such as silver foil, etc., is adhered to the inclined surface 
thereof. The reflection member 20 allows a detection light incident from 
the light emitting element of the recording/reproduction unit through the 
incident hole to undergo refraction and reflection on the inclined surface 
to guide it toward the front portion 2a of the cover member 3 to irradiate 
it onto the magnetic tape 12 traveling along the front portion 2a. 
Moreover, substantially at the central portion of the front portion 2a of 
the cover member 3, an opening portion 21 for driving the magnetic tape is 
opened. Further, at the front portion 2a of the cover member 3, a 
terminating end detection portion 22 is provided adjacent to the magnetic 
tape driving opening portion 21. This terminating end detection portion 22 
is formed by a thin thickness portion positioned in a manner opposite to 
the above-described reflection member 20. 
Moreover, in this tape cartridge 1 including a cover member 3 and the base 
plate 4 combined to form the cartridge body 2, the belt drive roller 17 
attached on the base plate 4 is positioned within the driving opening 
portion 21 of the side of the cover member 3. This belt drive roller 17 is 
positioned so that a portion of the outer circumferential portion of the 
drive flange portion is faced exteriorily from the driving opening portion 
21 by the belt drive roller 17. In this embodiment, the 
recording/reproduction opening portion 7 is ordinarily closed by the cover 
body 8. 
Further, in the tape cartridge 1 according to this invention, as shown in 
FIGS. 6 and 7, an erroneous recording prevention mechanism 31 is provided 
for setting a recording permissible state where recording of information 
signals is permitted with respect to the magnetic tape 12 accommodated 
within the tape cartridge 1 and an erroneous recording prevention state 
where recording of information signals onto the magnetic tape 12 is not 
permitted. This erroneous recording prevention mechanism 31 is formed at 
the cover member 3 opposite to the erroneous recording detection mechanism 
31 disposed at the recording/reproduction unit side when the tape 
cartridge 1 is loaded into the recording/reproduction unit. The erroneous 
recording prevention mechanism 31 comprises an erroneous recording 
prevention member 37 attached at the position on the side opposite to the 
cover body 8 disposed at the front portion 2a of the cover member 3. This 
erroneous recording prevention member 37 is formed by molding synthetic 
resin material including polyacetal resin or ABS resin, etc. The erroneous 
recording prevention member 37 can be elastic in nature due to its 
formation by a molding synthetic resin. Further, since smoothness is 
rendered thereto, secure attachment can be achieved with respect to the 
cartridge body 2, and smooth operability can be realized. 
Further, at the portion where the erroneous recording prevention member 37 
is disposed on the cover member 3, as shown in FIGS. 9 and 10, a guide 
recessed portion 33 is provided within which the erroneous recording 
prevention member 37 is moved, and an erroneous recording detection hole 
32 opened and closed by the erroneous recording prevention member 37. 
The guide recessed portion 33 within which the erroneous recording 
prevention member 37 is disposed extends over the front 25 of the cover 
member 3 and a top plate 30 of the cover member 3 which is a surface 
portion opposite to the base plate 4 of the cartridge body 2. The bottom 
surface portion 34 of the guide recessed portion 33 serves as the portion 
clamped or held by the erroneous recording prevention member 37. This 
bottom surface portion 34 is formed in a plate form in parallel to the top 
plate 30 of the cover member 3 due to the erroneous recording detection 
hole 32 being formed at the front 25 of the cover member 3. 
Further, at the internal end side of the portion extending on the top plate 
30 of the guide recessed portion 33, an insertion groove 29 is formed into 
which an insertion piece 41 provided at the erroneous recording prevention 
member 37 is inserted as described later. This insertion groove 29 is 
formed in a portion of the bottom surface portion 34. An inclined surface 
39a of the bottom surface 34 faces the insertion groove 29 so as to be 
able to guide insertion of the insertion piece 41 and to guarantee smooth 
movement of the insertion piece 41. 
Further, at the inner surface side of the top plate 30 of the cover member 
3 opposite to the internal end of the guide recessed portion 33, an 
engagement recessed portion 36 is formed with which the insertion piece 41 
of the erroneous recording prevention member 37 is engaged and adapted to 
guide movement of the insertion piece 41. The engagement recessed portion 
36 includes a supporting portion 35 along the top plate for pressing the 
insertion portion 41. 
Further, within the engagement recessed portion 36, first and second 
holding recessed portions 43, 44 are provided as positioning mechanisms 
such that when the erroneous recording prevention member 37 disposed 
within the guide recessed portion 33 is moved to its first position where 
it closes the erroneous recording detection hole 32, as shown in FIG. 11, 
and to its second position where it opens the erroneous recording 
detection hole 32, a holding projection 42 projecting from the insertion 
piece 41 is engaged with the respective first and second holding recessed 
portions 43, 44 to secure proper positioning of the erroneous recording 
prevention member 37 when it is moved to its first and second positions. 
Alternatively, this position mechanism includes a holding recessed portion 
provided at the side of the insertion piece 41 of the erroneous recording 
prevention member 37 with holding projections provided at the side of the 
engagement recessed portion 36 side. 
Meanwhile, the erroneous recording detection hole 32 opened or closed by 
the erroneous recording prevention member 37 is provided at the front 25 
of the cover member 3 positioned within the guide recessed portion 33. 
This erroneous recording detection hole 32 is provided at the position 
opposite to the detection element of the erroneous recording detection 
mechanism disposed at the recording/reproduction unit side when the tape 
cartridge 1 is loaded into the recording/reproduction unit. In addition, 
the erroneous recording detection hole 32 allows the detection element of 
the erroneous recording detection mechanism to be projected toward the 
interior of the cartridge body 2. 
Further, the erroneous recording prevention member 37 attached at the cover 
member 3 positioned within the guide recessed portion 33 includes, at the 
base end portion side thereof, a portion of a detection member (detected 
portion when viewed from the recording medium device) 38 for actuating the 
erroneous recording detection mechanism disposed at the 
recording/reproduction unit side as shown in FIGS. 12 and 13, and a 
holding portion 45 for clamping or holding the bottom surface portion 34 
of the guide recessed portion 33. This holding portion 45 includes a 
movement guide piece 39 serving as a movement guide portion projected in a 
substantially vertical direction from the portion of the detection member 
38 and extended toward the top plate 30 side portion of the guide recessed 
portion 33, and a supporting piece 40 serving as a supporting portion 
projected from the portion of the detection member 38 substantially 
parallel to the movement guide piece 39. Namely, as shown in FIG. 12, the 
holding portion 45 is formed by the movement guide piece 39 and the 
supporting piece 40 so as to attain a channel shape in cross section, and 
is formed so as to hold or position the bottom surface portion 34 of the 
guide recessed portion 33 therebetween. 
In this case, the movement guide piece 39 is formed so as to have thickness 
substantially equal to the depth of the guide recessed portion 33, and is 
formed in substantially the same plane surface as the upper surface of the 
top plate 30 of the cover member 3 when the erroneous recording prevention 
member 37 is attached within the guide recessed portion 33. Moreover, at 
the inner surface of the front end side of the movement guide piece 39, an 
inclined guide surface 39a is formed along the inclined surface 34a formed 
on the bottom surface portion 34 of the guide recessed portion 33. In 
addition, at the inner surface of the front end side of the movement guide 
piece 35, chamfering portion 40a is provided for guiding insertion at the 
time of insertion into the cover member 3 at the front end portion side of 
the supporting piece 40. 
Further, at the front end side of the movement guide piece 39 which forms 
the holding portion 45 of the erroneous recording prevention member 37, an 
insertion piece 41 is provided which is inserted into the insertion groove 
29 provided at the bottom surface portion 34 of the guide recessed portion 
33 toward the inner surface side of the top plate 30 of the cover member 3 
when the erroneous recording prevention member 37 is attached to the cover 
member 3. This insertion piece 41 projects from the lower end side of the 
front end side of the movement guide piece 39, and an offset portion 41a 
is formed on the upper surface of the continuously connecting portion side 
of the movement guide piece 39. This offset portion 41a has a height 
substantially equal to the thickness of the pressing supporting portion 35 
of the cover member 3 side. In addition, at the front end side of the 
insertion piece 41, a chamfering portion 41b is provided for guiding 
insertion of the insertion piece 41 into the insertion groove 29. 
Moreover, at the upper surface side of the insertion piece 41, a holding 
projection 42 engaged with the first and second holding recessed portions 
43, 44 is formed within the engagement recessed portion 36 provided at the 
side of the cover member 3. This holding projection 42 is formed of a 
generally semi-circular shape in cross section having a circumferential 
circular arc surface for achieving smooth engagement/withdrawal with 
respect to the first and second holding recessed portions 43, 44. 
In order to attach the erroneous recording prevention member 37 to the 
cover member 3, the movement guide piece 39 faces the portion extended to 
the top plate 30 side of the guide recessed portion 33 provided at the 
cover member 3, and to face the supporting piece 40 to the erroneous 
recording prevention hole 32 to insert the erroneous recording prevention 
member 37 into the guide recessed portion 33 from the front 25 side of the 
cover member 3. At this time, the front end portion side of the insertion 
piece 41 is inserted into the insertion groove 29. When the erroneous 
recording prevention member 37 is inserted into the guide recessed portion 
33, the supporting piece 40 is inserted toward the lower surface side of 
the bottom surface portion 34 of the guide recessed portion 33 to hold or 
clamp the bottom surface portion 34 by the supporting piece 40 and the 
movement guide piece 39 thus to hold the bottom surface portion 34 by the 
holding portion 45. 
When the erroneous recording prevention member 37 is further inserted into 
the slide recessed portion 33, the insertion piece 41 is inserted toward 
the interior thereof along the inner surface of the pushing supporting 
piece 35 by the action of the chamfering portion 41a of the front end 
portion while the insertion piece 41 is caused to undergo elastic 
displacement in the thickness direction as shown in FIG. 10. In the 
condition where the erroneous recording prevention member 37 is securely 
pushed into the guide recessed portion 33, the insertion piece 41 comes 
into pressure contact with the inner surface side of the cover member 3 in 
the state caused to undergo elastic displacement toward the pushing 
supporting piece 35 side in the direction indicated by arrow C in FIG. 10 
so that elastic repulsive force is rendered thereto. Thus, the insertion 
piece 41 is relatively engaged with the engagement recessed portion 36. At 
this time, the insertion piece 41 is engaged into the engagement recessed 
portion 36 and is inserted toward the interior of the cartridge body 2 so 
that it does not project. Accordingly, there is no possibility that the 
space where the magnetic tape 12 travels and the space within which the 
tape reels 13a, 13b are accommodated within the cartridge body 2 may not 
be narrowed, thus making it possible to maintain the space within the 
cartridge body 2 to be relatively large. 
Moreover, the above-described elastic force of the insertion piece 41 
serves to push the inner surface thereof toward the bottom surface portion 
34 of the guide recessed portion 33 with respect to the movement guide 
piece 39 as reactive force. Thus, with respect to the erroneous recording 
prevention member 37, the holding or clamping state of the bottom surface 
portion 34 of the guide recessed portion 33 by the movement guide piece 39 
and the supporting piece 40 is retained, and they are securely combined or 
assembled within the guide recessed portion 33 by elastic repulsive force 
of the insertion piece 41 applied to the pressing supporting piece 35 so 
that slipping off is prevented. At this time, since elastic repulsive 
force of the insertion piece 41 is applied in a direction perpendicular to 
the movement direction of the erroneous recording prevention member 37, 
there is no possibility that it exerts significant influence on its 
operability. 
Further, with respect to the erroneous recording prevention member 37, in 
the state where it is attached into the guide recessed portion 33 by the 
above-described operation, the holding projection 42 provided on the 
insertion piece 41 is relatively engaged with any one of the first and 
second holding recessed portions 43, 44 provided within the engagement 
recessed portion 36 as shown in FIG. 10. The engagement state between the 
holding projection 42 and the first and second holding recessed portions 
43, 44 is securely held by the elastic repulsive force of the insertion 
portion 41. At this time, the portion of the detection member 38 of the 
erroneous recording prevention member 37 is opposed to the front 25 of the 
cover member 3 where the erroneous recording detection hole 32 is formed 
as shown in FIGS. 9 and 11. 
The erroneous recording prevention member 37 attached in a manner 
positioned within the guide recessed portion 33 provided at the cover 
member 3 in this way is moved in the direction indicated by arrow E and in 
the direction indicated by arrow F in FIGS. 6, 9 and 11 along the front 
portion 2a of the cartridge body 2 in such a manner that the holding 
portion 45 is guided by the bottom surface portion 34 of the guide 
recessed portion 33 and the insertion piece 41 is guided by the engagement 
recessed portion 36. When this erroneous recording prevention member 37 is 
moved from the first position shown in FIG. 11 to the second position 
shown in FIG. 9, or from the second position shown in FIG. 9 to the first 
position shown in FIG. 11, the insertion portion 41 is caused to undergo 
elastic deformation in the thickness direction. Thus, the holding 
projection 41 engaged with the first or second holding recessed portion 43 
or 44 moves in a manner riding on the bottom surface of the engagement 
recessed portion 36. When the erroneous recording prevention member 37 is 
moved to the first or second position, the holding projection 41 is 
relatively engaged with the first or second holding recessed portion 43 or 
44, and is thus held at the first or second position. As a result, the 
holding projection 41 is securely held at the first or second position. 
Meanwhile, in the tape cartridge 1 of this embodiment, when the erroneous 
recording prevention member 37 is moved to one side of the cartridge body 
2 as shown in FIG. 11 so that the portion of the detection member 38 is 
moved to (located at) the first position where it closes the erroneous 
recording detection hole 32 provided at the front 25 of the cover member 
3, recording of information signals can be made with respect to the 
magnetic tape 12 accommodated within the cartridge body 2. Moreover, when 
the erroneous recording prevention member 37 is moved from the first 
position shown in FIG. 9 toward the internal side of the cartridge body 2 
in the direction indicated by arrow F in FIG. 11 so that the portion of 
the detection member 38 is moved to (located at) the second position where 
it opens the erroneous recording detection hole 32, the erroneous 
recording prevention state results where recording of information signals 
with respect to the magnetic tape 12 accommodated within the cartridge 
body 2 is not possible. 
Namely, in the recording/reproduction unit into which the tape cartridge 1 
of this embodiment is loaded, a detection mechanism for detecting the 
portion of the detection member 38 of the erroneous recording prevention 
member 37 is provided. This recording/reproduction unit is adapted so that 
when the portion of the detection member 38 is detected by the detection 
mechanism, selection of the recording operation mode where recording of 
information signals can be made with respect to the magnetic tape 12 is 
permitted. When detection of the portion of detection 38 is not carried 
out by the detection mechanism, selection of the recording operation mode 
is not possible. 
An example of recording/reproduction unit 50 into which the tape cartridge 
1 of this embodiment is loaded will now be described with reference to the 
attached drawings. 
In this recording/reproduction unit 50, as shown in FIG. 14, a cartridge 
loading portion 54 is provided into which the tape cartridge 1 of this 
embodiment is inserted through a cartridge insertion/withdrawal hole 53 
provided at a front panel 52 of a unit body 51 to load the tape cartridge 
1 within the unit body 51. At both sides of the cartridge loading portion 
54, projected portions 56, 55 are provided respectively engaged with 
engagement grooves 2b, 2c provided at the both sides of the front side of 
the tape cartridge 1. The tape cartridge 1 is inserted into the unit body 
51 through the cartridge insertion/withdrawal hole 53 in the direction 
indicated by arrow G in FIG. 14 with the front portion 2a side where the 
erroneous recording prevention member 37 is attached being along the 
insertion end. At this time, the tape cartridge 1 is inserted in the state 
where engagement grooves 2b, 2c are respectively engaged with the 
projected portions 56, 55. When the projected portion 56 is engaged with 
the engagement groove 2b, the cover body 8 is rotated by the front end of 
the projected portion 56 against biasing force of the torsion spring 10 to 
open the opening portion 7 for recording/reproduction. 
At the cartridge loading portion 54, positioning projections are provided 
for proper positioning in the insertion direction of the tape cartridge 1 
and pressing supporting means. The tape cartridge 1 is loaded into the 
cartridge loading portion 54 so that the engagement grooves 2b, 2c are 
respectively engaged with the projected portions 56, 55, whereby the 
insertion position is caused to undergo positioning by the positioning 
projection, and the loading position is caused to undergo positioning by 
the pressing supporting means. 
Moreover, a magnetic head unit 57 and a drive roller 58 are disposed within 
the unit body 51. When the tape cartridge 1 is loaded into the cartridge 
loading portion 54, the magnetic head unit 57 is inserted into the opening 
portion 7 for recording/reproduction to come into slide contact with the 
magnetic tape 12, and the drive roller 58 is caused to come into pressure 
contact with the belt drive roller 17 through the driving opening portion 
21. In this case, when the drive roller 58 is driven, the belt drive 
roller 17 of the tape cartridge 1 side is rotationally operated. As a 
result, the magnetic tape 12 travels at a constant velocity. Thus, 
recording/reproduction of information signals with respect to the magnetic 
tape 12 is performed by the magnetic head 57 slidably in contact with the 
magnetic tape 12. 
Meanwhile, in the recording/reproduction unit 50 into which the tape 
cartridge 1 of this embodiment is loaded, a detection mechanism 61 is 
provided for detecting loading of the tape cartridge 1 with respect to the 
cartridge loading portion 54 and for detecting the portion of detection 38 
of the erroneous recording prevention member 37 attached to the tape 
cartridge 1. As shown in FIG. 15, this detection mechanism 61 is provided 
at the position opposite to the front portion 2a of the tape cartridge 1 
loaded with respect to the cartridge loading portion 54 and at the 
position opposite to the erroneous recording prevention member 37 when the 
erroneous recording prevention member 37 is located at the first position 
where it closes the erroneous recording detection hole 32 as shown in FIG. 
11. 
The detection mechanism 61 includes, as shown in FIG. 16, a first detection 
element 62 for detecting the portion of the detection member 38 of the 
erroneous recording prevention member 37, and a second detection element 
63 for detecting that the tape cartridge 1 is loaded with respect to the 
cartridge loading portion 54 in parallel in the height direction. Namely, 
the first detection element 62 is disposed in a manner opposite to the 
portion of the detection member 38 of the erroneous recording prevention 
member 37 positioned at the upper surface side of the cartridge body 2, 
and the second detection element 63 is disposed opposite to the front 
portion 2a of the cartridge body 2 of the lower side of the erroneous 
recording prevention member 37. 
The detection state of the detection mechanism 61 when the tape cartridge 1 
loaded in the cartridge loading portion is moved between its first 
position, where the erroneous recording prevention member 37 closes the 
erroneous recording detection hole 32, and its second position where the 
erroneous recording prevention member 37 opens the erroneous recording 
detection hole 32 will now be described. 
When the tape cartridge 1 loaded in the cartridge loading portion 54 is 
moved to the first position where the erroneous recording prevention 
member 37 closes the erroneous recording detection hole 32, the first 
detection element 62 is pressed by the portion of the detection member 38 
of the erroneous recording prevention member 37, and the second detection 
element 63 is pressed by the front portion 2a of the cartridge body 2. 
Since the second detection element 63 is pressed, it is detected that the 
tape cartridge 1 is loaded with respect to the cartridge loading portion 
54. As the result of the fact that the first detection element 62 is 
pressed, it is detected that the erroneous recording prevention member 37 
is located at its first position. When the erroneous recording prevention 
member 37 is detected by the detection mechanism 61, it determines that 
the tape cartridge 1 is loaded with respect thereto in a condition such 
that information signals can be recorded onto the magnetic tape 12. When 
it is detected by the detection mechanism 61 that the tape cartridge 1 is 
in a recordable state, the recording/reproducing unit 50 is placed in the 
state where recording operation mode can be selected. By selecting the 
recording operation mode, recording of information signals is carried out 
with respect to the magnetic tape 12. 
Moreover, when the tape cartridge 1 loaded into the cartridge loading 
portion 5c is moved to its second position where the erroneous recording 
prevention member 37 opens the erroneous recording detection hole 32, the 
second detection element 63 is pressed by the front portion 2a of the 
cartridge body 2, but the first detection element 62 projects into the 
erroneous recording detection hole 32 without being pressed by the portion 
of the detection member 38 of the erroneous recording prevention member 
37. In this case, it is detected that the tape cartridge 1 is loaded with 
respect to the cartridge loading portion 54. However, since there is no 
possibility that detection of the erroneous recording detection member 37 
is carried out, it is determined that the tape cartridge 1 is loaded in a 
condition where information signals onto the magnetic tape 12 cannot be 
recorded. When it is detected by the detection mechanism 61 that the tape 
cartridge 1 is in the recording unable state, selection of the recording 
operation mode in the recording/reproducing unit 50 is limited. As a 
result, recording of information signals with respect to the magnetic tape 
12 is inhibited. Thus, information signals previously recorded on the 
magnetic tape 12 are protected. 
Alternatively, the erroneous recording prevention hole 32 may be positioned 
along the front side portion of the cartridge body 2 of the guide recessed 
portion 33 within which the erroneous recording prevention member 37 is 
disposed. 
In addition, an optical detection mechanism may be used as the detection 
mechanism 61 provided at the recording/reproduction unit 50 side. Namely, 
a pair of light emitting and receiving elements may be used to detect 
light reflected onto the tape cartridge 1 which is emitted from the light 
receiving element to thereby detect the presence or absence of the 
erroneous recording prevention member 37 or presence or absence of loading 
of the tape cartridge 1. 
In the above-described tape cartridge 1, the erroneous recording prevention 
member 37 holds therebetween a portion of the cartridge body 2, i.e., the 
bottom surface portion 34 of the guide recessed portion 33 by the holding 
portion 45 of the base end portion side, and the insertion piece 41 
provided at the front end side of the holding portion 45 which is in 
pressure contact with the surface of the internal side of the cartridge 
body 2. Accordingly, the erroneous recording prevention member 37 is 
firmly attached to the cartridge body 1. Even if impact is applied to the 
tape cartridge 1, the erroneous recording prevention means 37 is prevented 
from being easily moved. Thus, the erroneous recording prevention member 
37 is securely held at the first or second position, or is prevented from 
easily slipping off from the cartridge body 2. 
While the above-described tape cartridge is adapted so that the erroneous 
recording prevention member is moved in parallel to the front portion of 
the cartridge body to thereby determine a setting where information 
signals can be recorded and cannot be recorded, a configuration may be 
employed such that the erroneous recording prevention member is moved in a 
direction perpendicular to the front portion of the cartridge body, i.e., 
to the first position where the portion of the detection member of the 
erroneous recording prevention member is located at the front portion side 
of the cartridge body and the second position is extended toward the 
interior of the cartridge body to thereby allow the tape cartridge to be 
in the information signal recordable state and in the information signal 
recording unable state. 
A tape cartridge including an erroneous recording prevention member which 
is advanced or withdrawn in a direction perpendicular to the front portion 
of the cartridge body to determine the information signal recordable state 
or the information signal recording unable state will now be described as 
a second embodiment. 
It is to be noted that common reference numerals are respectively used with 
respect to features common to the previously described first embodiment 
and detailed explanation of these features will be omitted herein, and 
explanation will be provided below as to certain illustrative features 
shown in the figures. 
In the tape cartridge 101 of the second embodiment, similarly to the 
previously described first embodiment, as shown in FIG. 17, a guide 
recessed portion 133 is positioned so that an erroneous recording 
prevention member 137 of an erroneous recording prevention mechanism 131 
is provided at cover member 3. This guide recessed portion 133 is formed 
extending over the front portion 25 of the cover member 3 and top plate 30 
of the cover member 3 so as to form a surface opposite to base plate 4 of 
cartridge body 2. In this case, as shown in FIG. 17, the guide recessed 
portion 133 is formed with a width W.sub.2 substantially equal to width 
W.sub.1 of the erroneous recording prevention member 137 disposed 
therewithin. Namely, the guide recessed portion 133 is formed in a manner 
to linearly guide movement of the erroneous recording prevention member 
137. 
Thus, a bottom surface portion 134 of the guide recessed portion 133 is 
held or clamped by the erroneous recording prevention member 137. Since 
the erroneous recording prevention hole 132 is formed at the front portion 
25 of the cover member 3, this bottom surface portion 134 is formed as a 
plate-shaped portion parallel to the top plate 30 of the cover member 3. 
Further, at the internal end side of the portion extending on the top plate 
30 of the guide recessed portion 133, an insertion groove 129 is formed 
into which an insertion piece 141 provided at the erroneous recording 
prevention member 137 is inserted as described later. This insertion 
groove 129 is formed in the bottom surface portion 134. An inclined 
surface 134a faces the insertion groove 129 of the bottom surface portion 
134 for guiding insertion of the insertion piece 141. 
Moreover, at the inner surface side of the top plate 30 of the cover member 
3 opposite to the internal end of the guide recessed portion 133, as shown 
in FIG. 18, an engagement recessed portion 136 is formed with which the 
insertion piece 141 of the erroneous recording prevention member 137 is 
engaged. The portion where the engagement recessed portion 136 is formed 
of the top plate 30 serves as a pressing supporting portion 135 of the 
insertion piece 141. 
Further, at the engagement recessed portion 136, first and second 
engagement recessed portions 143, 144 are provided forming a positioning 
mechanism such that when the erroneous recording prevention member 137 
disposed at the guide recessed portion 133 is moved to the front portion 
2a of the cartridge body 2 as shown in FIG. 19, the erroneous recording 
prevention member 137 is positioned at its first position where it closes 
the erroneous recording detection hole 132 and is moved to the internal 
side of the cartridge body 2 as shown in FIG. 20 at its second position 
where it opens the erroneous recording detection hole 132, a holding 
projection 142 projecting from the insertion piece 141 is engaged with the 
respective first and second holding recessed portions 143, 144 to carry 
out positioning of the erroneous recording prevention member 137 when 
moved to the first and second positions of the erroneous recording 
prevention member 137. In this example, since the erroneous recording 
prevention member 137 is moved in before and after directions extending 
from the front portion 2a side of the cartridge body 2 toward the internal 
side in the direction indicated by arrow K and in the direction indicated 
by arrow J in FIG. 19, the first and second engagement holding recessed 
portions 143, 144 are provided in series in the before and after 
directions of the cartridge body 2. 
Also in the second embodiment, the positioning mechanism for carrying out 
positioning of the erroneous recording prevention member 137 may be such 
that holding recessed portion is provided at the insertion piece 141 side 
of the erroneous recording prevention member 137 and holding projections 
are provided at the side of the engagement recessed portion 136. 
Meanwhile, the erroneous recording detection hole 132 opened or closed by 
the erroneous recording prevention member 137 is provided at the front 
portion 25 of the cover member 3 when it is positioned within the guide 
recessed portion 133. Similarly to the previously described first 
embodiment, this erroneous recording detection hole 132 is provided in 
such a manner that it is located at the position opposite to the detection 
element of the erroneous recording detection mechanism disposed at the 
recording/reproduction apparatus side when the tape cartridge 1 is loaded 
into the recording/reproduction unit. 
The erroneous recording prevention member 137 includes, at the base end 
portion side thereof, as shown in FIGS. 17 and 18, a portion of a 
detection member (detected portion when viewed from the recording medium 
device) 138 for actuating the erroneous recording detection mechanism 
disposed at the recording/reproduction unit side, wherein a holding 
portion 145 for holding or clamping the bottom surface portion 134 of the 
guide recessed portion 133 of the cover member 3 is provided at the base 
end portion side where the portion of the detection member 138 is 
provided. This holding portion 145 includes a movement guide piece 139 
projecting from the portion of the detection member 138, and extending 
toward the top plate 30 side portion of the guide recessed portion 133, 
and a supporting piece 140 serving as a supporting portion projecting from 
the portion of detection 138 substantially in parallel to the movement 
guide piece 139. Namely, as shown in FIGS. 17 and 18, the holding portion 
145 is formed by the movement guide piece 139 and the supporting piece 140 
in a generally channel shape in cross section, and is formed to hold or 
clamp the bottom surface portion 134 of the guide recessed portion 133. 
In this example, the movement guide piece 139 is formed so as to have a 
thickness substantially equal to the depth of the guide recessed portion 
133, and is positioned substantially on the same plane surface as the 
upper surface of the top plate 30 of the cover member 3 when the erroneous 
recording prevention member 137 is attached within the guide recessed 
portion 133. 
At the front end side of the movement guide piece 139 constituting the 
holding portion 145 of the erroneous recording prevention member 137, the 
insertion piece 141 is provided which is adapted to be inserted into the 
insertion groove 129 provided at the bottom surface portion 134 of the 
guide recessed portion 133 and adapted to be inserted toward the inner 
surface side of the top plate 30 of the cover member 3 when the erroneous 
recording prevention member 137 is attached to the cover member 3. This 
insertion piece 141 projects from the lower end side of the front end side 
of the movement guide piece 139, wherein an offset portion 141 a is formed 
on the upper surface of continuously connecting portion side of the 
movement guide piece 139. This offset portion 141a has a height 
substantially equal to the thickness of the pressing supporting portion 
135 of the side of the cover member 3. 
Moreover, at the upper surface side of the insertion piece 141, as 
described above, a holding projection 142 projects therefrom which is 
engaged with the first and second holding recessed portions 143, 144 
formed within the engagement recessed portion 136 provided at the side of 
the cover member 3. This holding projection 142 is formed so as to have 
semi-circular shape in cross section having a circumferential circular arc 
surface to achieve smooth engagement/withdrawal (disengagement) with 
respect to the first and second holding recessed portions 143, 144. 
In order to attach the erroneous recording prevention member 137 formed as 
described above to the cover member 3, the movement guide piece 139 is 
faced to the portion extended toward the top plate 30 side of the guide 
recessed portion 133 provided at the cover member 3 and the supporting 
piece 140 is faced to the erroneous recording prevention hole 132 to 
insert the erroneous recording prevention member 137 into the guide 
recessed portion 133 from the front portion 25 side of the cover member 3. 
At this time, the front end portion side of the insertion piece 141 is 
faced to the insertion groove 129. When the erroneous recording prevention 
member 137 is inserted into the guide recessed portion 133, the supporting 
piece 140 is inserted toward the lower surface side of the bottom surface 
portion 134 of the guide recessed portion 133 to hold or clamp the bottom 
surface portion 134 by the supporting piece 140 and the movement guide 
piece 139 thus to hold the bottom surface portion 134 by the holding 
portion 145. 
When the erroneous recording prevention member 137 is further inserted into 
the slide recessed portion 133, the insertion piece 141 is inserted toward 
the interior along the inner surface of the pressing supporting piece 135 
while undergoing elastic displacement in the thickness direction thereof. 
In the state where the erroneous recording prevention member 137 is 
securely pushed into the guide recessed portion 133, the insertion piece 
141 comes into pressure contact with the inner surface side of the cover 
member 3 in the state where it is caused to undergo elastic displacement 
toward the pressing supporting piece 135 side in the direction indicated 
by arrow H in FIG. 18 so that elastic repulsive force is rendered thereto, 
thus to relatively become engaged with the engagement recessed portion 
136. At this time, the insertion piece 141 is engaged into the engagement 
recessed portion 136, and is thus inserted toward the interior of the 
cartridge body 2 so that it does not project. Accordingly, there is no 
possibility that the space within which the magnetic tape 12 travels and 
the space within which the tape reels 13a, 13b are accommodated within the 
cartridge body 2 may be narrowed. 
Moreover, the above-described elastic force of the insertion piece 141 
serves to press the internal surface thereof onto the bottom surface 
portion 134 of the guide recessed portion 133 with respect to the movement 
guide piece 139 as reactive force. Thus, in the erroneous recording 
prevention member 137, the holding or clamping state of the bottom surface 
portion 134 of the guide recessed portion 133 by the movement guide piece 
139 and the supporting piece 140 is held, and the erroneous recording 
prevention member 137 is securely combined with the guide recessed portion 
133 therewithin by elastic repulsive force of the insertion piece 141 
applied to the pressing supporting piece 135 so that slipping off is 
prevented. At this time, the elastic repulsive force of the insertion 
piece 141 is applied in a direction perpendicular to the movement 
direction of the erroneous recording prevention member 137. For this 
reason, any unfavorable phenomenon exerting a bad influence on the 
operability is also prevented. 
In the state where the erroneous recording prevention member 137 is 
attached within the guide recessed portion 133 by the above-described 
operation, the engagement projection 142 provided on the insertion piece 
141 is relatively engaged with any one of the first and second holding 
recessed portions 143, 144 provided within the engagement recessed portion 
136 as shown in FIGS. 19 and 20. The engagement state between the holding 
projection 142 and the first and second holding recessed portions 143, 144 
is securely held by elastic repulsive force of the insertion piece 141. At 
this time, the portion of the detection member 138 of the erroneous 
recording prevention member 137 is opposed to the erroneous recording 
prevention hole 132 formed at the front portion 25 of the cover member 3. 
The erroneous recording prevention member 137 positioned within the guide 
recessed portion 133 is moved in the direction indicated by arrow J and in 
the direction indicated by arrow K in FIGS. 19 and 20 within the range 
between a first position where the erroneous recording prevention member 
137 is moved to the front portion 2a of the cartridge body 2, at which the 
portion of the detection member 138 is caused to be flush with the front 
of the cover member 3 to close the erroneous recording prevention hole 132 
as shown in FIG. 19 and a second position where the portion of the 
detection member 138 is moved toward the internal side of the cartridge 
body 2 to open the erroneous recording prevention hole 132 as shown in 
FIG. 20 while the holding portion 145 is guided by the bottom surface 
portion 134 of the guide recessed portion 133 and the insertion piece 141 
is guided by the engagement recessed portion 136. This erroneous recording 
prevention member 137 is adapted so that when it is moved from the first 
position shown in FIG. 19 to the second position shown in FIG. 20, or from 
the second position shown in FIG. 20 to the first position shown in FIG. 
19, the insertion portion 141 is caused to undergo elastic displacement in 
the thickness direction thereof, and the holding projection 141 engaged 
with the first or second holding recessed portions 143 or 144 is moved 
riding on the bottom surface of the engagement recessed portion 136. When 
the erroneous recording prevention member 137 is moved to its first or 
second positions, the holding projection 141 is relatively engaged with 
the first or second holding recessed portions 143 or 144 so that it is 
held at the first or second position. Thus, the erroneous recording 
prevention member 137 is securely held at the first or second positions. 
Meanwhile, in the case of the tape cartridge 101 of this embodiment, since 
the erroneous recording prevention member 137 is moved in a manner ranging 
from the front portion 2a side of the cartridge body 2 toward the internal 
side thereof, a cut portion 134b of a width W.sub.3 for permitting the 
movement of the erroneous recording prevention member 137 is provided, as 
shown in FIG. 18, at the front side of the bottom surface portion 134 of 
the guide recessed portion 133. 
Further, in the tape cartridge 101 of this embodiment, when the portion of 
the detection member 138 of the erroneous recording prevention member 137 
is moved, as shown in FIG. 19, to the first position where it becomes 
flush with the front portion 2a of the cartridge body 2 so that it is 
located at its first position where it closes the erroneous recording 
detection hole 132, recording of information signals can be made with 
respect to the magnetic tape 12 accommodated within the cartridge body 2. 
Moreover, when the erroneous recording prevention member 137 is moved from 
the first position shown in FIG. 19 toward the internal side of the 
cartridge body 2 in the direction indicated by arrow K in FIGS. 19 and 20 
so that it is located at its second position where the portion of 
detection member 138 opens the erroneous recording detection hole 132, an 
erroneous recording prevention state results where recording of 
information signals with respect to the magnetic tape 12 accommodated 
within the cartridge body 2 is not permitted to be performed. 
Namely, also in the case of the tape cartridge 101 of this embodiment, 
similarly to the previously described tape cartridge 1, when the portion 
of the detection member 138 is detected by the detection mechanism of the 
recording/reproduction unit side into which this tape cartridge 101 is 
loaded, selection of the recording operation mode for permitting recording 
of information signals with respect to the magnetic tape 12 can be made. 
When the portion of the detection member 138 is not determined by the 
detection mechanism, selection of the recording operation mode is not 
permitted to be carried out. 
While the above-described tape cartridges of the first and second 
embodiments are adapted so that the erroneous recording prevention member 
is linearly moved with respect to the cartridge body to thereby set the 
tape cartridge so that it is in the information signal recordable state 
and the information signal recording unable state, a configuration may be 
employed such that the erroneous recording prevention member is rotated 
with respect to the cartridge body, whereby the erroneous recording 
prevention member is moved to a first position where the portion of the 
detection member thereof is detected by the detection mechanism of the 
recording/reproduction unit side and a second position where it is not 
detected by the detection mechanism. 
An erroneous recording prevention member which is rotated with respect to 
the cartridge body to set the tape cartridge so that it is in the 
information signal recordable state or the information signal recording 
unable state will now be described as a third embodiment. 
It is to be noted that common reference numerals are respectively used with 
respect to features common to the previously described first embodiment 
and detailed explanation of these features will be omitted, and 
explanation will be provided below only as to certain illustrative 
features shown in the figures. 
In the tape cartridge 201 of the third embodiment, similarly to the 
previously described first embodiment, as shown in FIG. 21, a guide 
recessed portion 233 is provided at cover member 3 where an erroneous 
recording prevention member 237 including an erroneous recording 
prevention mechanism 231 is disposed. This guide recessed portion 233 is 
formed extending over a front portion 25 of the cover member 3 and a top 
plate 30 of the cover member 3 forming a surface opposite to base plate 4 
of cartridge body 2. In this case, the guide recessed portion 233 is sized 
for permitting rotation of the erroneous recording prevention member 237 
disposed therewithin as shown in FIGS. 21, 23 and 24. 
Further, a bottom surface portion 234 of the guide recessed portion 233 
serves as the portion held or clamped by the erroneous recording 
prevention member 237. An erroneous recording prevention hole 232 is 
formed at the front portion 25 of cover member 3, whereby this bottom 
surface portion 234 is formed as a plate-shaped portion in parallel to the 
top plate 30 of the cover member 3. At the front end portion side facing 
the front portion 2a of the cartridge body 2 of the bottom surface portion 
234, a rotational guide portion 251 is formed which has a slightly curved 
inclined surface so as to permit rotation of the erroneous recording 
prevention member 237. 
Further, at the internal end side of the portion extending on the top plate 
30 of the guide recessed portion 233, an insertion groove 229 is formed 
into which an insertion piece 241 provided at the erroneous recording 
prevention member 237 is inserted as described later. This insertion 
groove 229 is formed in the bottom surface portion 234. The plane surface 
facing in the insertion groove 229 of the bottom surface portion 234 is an 
inclined surface 234a for guiding insertion of the insertion piece 241. 
At the internal surface side of the top plate 30 of the cover member 3 
opposite to the internal end of the guide recessed portion 233, an 
engagement recessed portion 236 with which the insertion piece 241 of the 
erroneous recording prevention member 237 is engaged is formed as shown in 
FIG. 22. The portion where the engagement recessed portion 236 is formed 
of the top plate 30 serves as a pressing supporting portion 235 of the 
insertion piece 241. 
In addition, within the engagement recessed portion 236, an engagement hole 
253 is provided which provides a rotational fulcrum portion 252 for 
rotatably supporting the erroneous recording prevention member 237 so that 
the erroneous recording prevention member 237 disposed within the guide 
recessed portion 233 is rotated in such a manner that it is located at a 
first position where it is moved toward the side of the cartridge body 2 
shown in FIG. 24 so that it closes the portion to which the detection 
element of the detection mechanism of the recording/reproduction unit side 
is opposed to the erroneous recording hole 232, and a second position, 
where the erroneous recording prevention member 237 is rotated (moved) 
toward the central portion side of the front portion 2a of the cartridge 
body 2 as shown in FIG. 23 to open the portion to which the detection 
element of the detection mechanism of the recording/reproduction unit side 
is opposed to the erroneous recording detection hole 232. An engagement 
projection 254 projected on the insertion piece 241 of the erroneous 
recording prevention member 237 is engaged with the engagement hole 253 to 
thereby provide the rotational fulcrum portion 252. 
Alternatively, the engagement hole 253 and the engagement projection 254 
providing the rotational fulcrum portion 252 may be provided so as to have 
the relationship opposite to the above. Namely, a configuration can be 
employed in which the engagement hole 253 is provided at the insertion 
piece 241 side of the erroneous recording prevention member 237 and the 
engagement projection 254 is provided at the engagement recessed portion 
236 side. 
Further, within the engagement recessed portion 236, a rotation limiting 
projection 255 projects such that when the erroneous recording prevention 
member 237 is rotated about the rotational fulcrum portion 252, the 
rotation limiting projection 255 limits the rotational locus of the 
erroneous recording prevention member 237 to prevent the erroneous 
recording prevention member 237 from slipping off from the rotational 
fulcrum portion 252. 
Moreover, at the bottom surface portion 234 of the guide recessed portion 
233, a holding recessed portion 243 is provided such that when the 
erroneous recording prevention member 237 is rotated so that it is placed 
at its second position shown in FIG. 24, a holding projection 242 provided 
on a rotational guide piece 239 forming a holding portion 245 of the 
erroneous recording prevention member 237 is held within the holding 
recessed portion 243. The holding projection 242 and the holding recessed 
portion 243 constitute a positioning mechanism for positioning the 
rotational position of the erroneous recording prevention member 237. 
Furthermore, at one side of the guide recessed portion 236 therewithin, as 
shown in FIG. 21, a jig insertion groove 256 is formed into which a jig 
for allowing the erroneous recording prevention member 237 to undergo 
rotational operation is inserted. 
Further, the erroneous recording prevention member 237 attached to the 
cover member 3 constituting the cartridge body 2 in the state positioned 
within the guide recessed portion 233 includes, at the base end portion 
side thereof, as shown in FIGS. 21 and 22, a portion of a detection member 
(detected portion when viewed from the recording medium device) 238 for 
actuating the erroneous recording detection mechanism disposed at the 
recording/reproduction unit side, wherein the holding portion 245 for 
holding or clamping the bottom surface portion 234 of the guide recessed 
portion 233 is provided at the base end portion side where the portion of 
the detection member 238 is provided. This holding portion 245 is formed 
by a rotational guide piece 239 which is the rotational guide portion 
extended toward the top plate 30 side portion of the guide recessed 
portion 233, and a supporting piece 240 serving as a supporting portion 
projected from the portion of the detection member 238 substantially in 
parallel in a manner opposite to the rotational guide piece 239. Namely, 
as shown in FIGS. 21 and 22, the holding portion 245 is formed by the 
rotational guide piece 239 and the supporting piece 240 so as to be 
generally channel shaped in cross section, and is formed so as to hold or 
clamp the bottom surface portion 234 of the guide recessed portion 233. 
Additionally, the portion of the detection member 238 provided at the 
erroneous recording prevention member 237 of this embodiment is 
positioned, as shown in FIGS. 21, 23 and 24, in a manner inclined with 
respect to the holding portion 245 slightly curved corresponding to the 
rotational locus of the erroneous recording prevention member 237. 
In this case, the rotational guide piece 239 is formed so as to have a 
thickness substantially equal to the depth of the guide recessed portion 
233, and is adapted so that when the erroneous recording prevention member 
237 is attached within the guide recessed portion 233, the rotational 
guide piece 239 is formed substantially on the same plane as the upper 
surface of the top plate 30 of the cover member 3. 
Further, at the front end side of the rotational guide piece 239 forming 
the holding portion 245 of the erroneous recording prevention member 237, 
the insertion piece 241 is provided such that when the erroneous recording 
prevention member 237 is attached to the cover member 3, the insertion 
piece 241 is inserted into the insertion groove 229 provided at the bottom 
surface portion 234 of the guide recessed portion 233 and is inserted 
toward the internal surface side of the top plate 30 of the cover member 
3. This insertion piece 241 projects from the lower end side of the front 
end side of the movement guide piece 239, and an offset portion 241 a is 
formed on the upper surface of the continuously connecting portion side of 
the rotational guide piece 239. This offset portion 241a has a height 
substantially equal to the thickness of the pressing supporting portion 
235 of the cover member 3 side. 
Moreover, at the upper surface side of the insertion piece 241, as 
described above, the engagement projection 254 of the rotational fulcrum 
portion 252 is provided. 
In order to attach the erroneous recording prevention member 237 as 
described above to the cover member 3, the rotational guide piece 239 is 
faced toward the portion extended toward the top plate 30 side of the 
guide recessed portion 233 provided at the cover member 3 and the 
supporting piece 240 is faced toward the erroneous recording prevention 
hole 232 to insert the erroneous recording prevention member 237 into the 
guide recessed portion 233 from the front portion 25 side of the cover 
member 3. At this time, the front end portion side of the insertion piece 
241 is faced to the insertion groove 229. When the erroneous recording 
prevention member 237 is inserted into the guide recessed portion 233, the 
supporting piece 240 is inserted toward the lower surface side of the 
bottom surface portion 234 of the guide recessed portion 233 to hold or 
clamp the bottom surface portion 234 by the supporting piece 240 and the 
rotational guide piece 239 thus to hold the bottom surface portion 234 by 
the holding portion 245. 
When the erroneous recording prevention member 237 is further inserted into 
the slide recessed portion 233, the insertion piece 241 is inserted toward 
the interior along the inner surface of the pressing supporting piece 235 
while the insertion piece 241 undergoes elastic displacement in the 
thickness direction thereof. In the state where the erroneous recording 
prevention member 237 is securely pushed into the guide recessed portion 
233, the insertion piece 241 comes into pressure contact with the inner 
surface side of the cover member 3 and undergoes elastic displacement 
toward the pressing supporting piece 235 side in the direction indicated 
by arrow M in FIG. 22 so that elastic repulsive force is rendered thereto, 
and is thus relatively engaged with the engagement recessed portion 236. 
In this case, the above-mentioned elastic repulsive force of the insertion 
piece 241 is applied so as to press the internal surface thereof onto the 
bottom surface portion 234 of the guide recessed portion 233 with respect 
to the movement guide piece 239 as reactive force. Thus, in the erroneous 
recording prevention member 237, the bottom surface portion 234 of the 
guide recessed portion 233 is held by the rotational guide piece 239 and 
the supporting piece 240, and the erroneous recording prevention member 
237 is securely combined with the guide recessed portion 233 therewithin 
by elastic repulsive force of the insertion piece 241 applied to the 
pressing supporting piece 235. Thus, slipping off is prevented. 
When the insertion piece 214 is caused to be engaged with the engagement 
recessed portion 236 as described above, the engagement projection 254 
provided on the insertion piece 214 is engaged with the engagement hole 
253 of the engagement recessed portion 236 side as shown in FIG. 22. Then, 
the erroneous recording prevention member 237 is attached to the cartridge 
body 2 so that it can be rotated in the direction indicated by arrow P and 
in the direction indicated by arrow Q in FIGS. 23 and 24, with the 
engagement projection 254 engaged with the engagement hole 253 acting as 
the rotational fulcrum, within the guide recessed portion 233. Thus, the 
erroneous recording prevention member 237 is rotated in the direction 
indicated by arrow P and in the direction indicated by arrow Q in FIGS. 23 
and 24 with the rotational fulcrum portion 252 being the pivot center 
within the range between the first position where the erroneous recording 
prevention hole 232 is closed by the portion of the detection member 238 
as shown in FIG. 24 and the second position where the portion of the 
detection member 238 opens the erroneous recording prevention hole 232 as 
shown in FIG. 23 while the holding portion 245 is guided by the bottom 
surface portion 234 of the guide recessed portion 233 and the insertion 
piece 241 is guided by the engagement recessed portion 236. When the 
erroneous recording prevention member 237 is rotated so that it is placed 
at the first position shown in FIG. 24, the holding projection 242 is 
engaged with the holding recessed portion 243 to limit rotation, whereby 
the portion of the detection member 238 closes the erroneous recording 
detection hole 232 thus to securely maintain movement of the erroneous 
recording prevention member 237 to the first position where recording of 
information signals can be made with respect to the magnetic tape 12. 
Namely, the tape cartridge 201 of this embodiment is such that when the 
portion of the detection member 238 of the erroneous recording prevention 
member 237 is rotated so that it is positioned at one side of the 
cartridge body 2 as shown in FIG. 24, whereby it is located at the first 
position where it closes the erroneous recording detection hole 232, 
recording of information signals can be made with respect to the magnetic 
tape 12 accommodated within the cartridge body 2. Moreover, when the 
erroneous recording prevention member 237 is rotated in the direction 
indicated by arrow P in FIG. 24 from the first position shown in FIG. 24 
so that the portion of the detection member 238 is moved to the second 
position as shown in FIG. 23 where the portion of the detection member 238 
opens the erroneous recording detection hole 232, recording of information 
signals with respect to the magnetic tape 12 accommodated within the 
cartridge body 2 is not permitted to be performed. 
Namely, also in the tape cartridge 201 of this embodiment, similarly to the 
previously described respective tape cartridges 1, 101, when the portion 
of the detection member 238 is detected by the detection mechanism of the 
recording/reproduction unit side into which the tape cartridge 201 is 
loaded, selection of the recording operation mode for permitting recording 
of information signals with respect to the magnetic tape 12 can be made. 
When the portion of the detection member 238 is not performed by the 
detection mechanism, selection of the recording operation mode is not 
permitted to be performed. 
Since the above-described tape cartridge 201 of the third embodiment is 
designed so that the erroneous recording prevention member 237 is only 
rotated within the range between the first and second positions with the 
rotational fulcrum portion 252 being the pivot center, there is the 
possibility that when the erroneous recording prevention member 237 is 
attached so that it does not protrude from the cartridge body 2 and is 
moved to the first position shown in FIG. 24 where it is obliquely rotated 
with respect to the cartridge body 2, the portion of the detection member 
238 may be positioned inwardly of the cartridge body 2, thus failing to 
precisely detect the portion of detection 238 by the detection mechanism 
of the recording/reproduction unit. 
In view of the above, it is desirable that where the erroneous recording 
prevention member 237 is rotatably attached to the cartridge body 2, it is 
advanced or withdrawn in before and after directions of the cartridge body 
2 along with its consequent rotation. 
A tape cartridge 303 of a fourth preferred embodiment adapted so that the 
erroneous recording prevention member 237 can be rotated and is advanced 
and withdrawn with respect to the cartridge body 2 as stated above will be 
described. Since features except for the rotational fulcrum portion are 
common to those of the third embodiment in this tape cartridge 303, 
reference numerals of common features for the third and fourth preferred 
embodiments are the same and detailed explanation will therefore be 
omitted. 
In the tape cartridge 303 of the fourth embodiment, an engagement hole 353 
with which an engagement projection 354 provided at the erroneous 
recording prevention member 237 side forming a rotational fulcrum portion 
352 for rotatably supporting the erroneous recording prevention member 237 
with respect to the cartridge body 2 is formed by an elongated hole in 
which the length direction is caused to be before and after directions of 
the cartridge body 2 as shown in FIGS. 25 and 26. By placing the 
engagement hole 353 by the elongated hole as aforedescribed, when the 
erroneous recording prevention member 237 is rotated from the second 
position where it opens the erroneous recording detection hole 232 as 
shown in FIG. 25 to not permit recording of information signals with 
respect to the tape cartridge 303 in the direction indicated by arrow Q in 
FIGS. 25 and 26 of the first position direction where the erroneous 
recording detection hole 232 shown in FIG. 26 is closed to permit 
recording of information signals with respect to the tape cartridge 303 
shown in FIG. 26, the erroneous recording prevention member 237 may be 
moved toward the front portion 2a side of the cartridge body 2 in the 
direction indicated by arrow S in FIG. 26. As a result, when the erroneous 
recording prevention member 237 is rotated so that it is placed at the 
first position as shown in FIG. 26, the erroneous recording detection 
portion 238 is permitted to be substantially flush with the front portion 
2a of the cartridge body 2. Thus, the portion of the detection member 238 
can be precisely detected by the detection mechanism of the 
recording/reproduction unit side. 
In the tape cartridge 303 of the fourth embodiment, a holding mechanism is 
provided such that when the erroneous recording prevention member 237 is 
moved to the first position and the second position, it holds the 
erroneous recording prevention member 237. Similarly to the previously 
described respective embodiments, this holding mechanism includes a 
holding projection 355 which is provided on the inner surface of 
rotational guide piece 239 of the erroneous recording prevention member 
237, and holding recessed portions 356, 357 where the holding projection 
355 is held are provided on bottom surface portion 234 of guide recessed 
portion 233 within which the rotational guide piece 239 is rotated. 
While, in the above-described tape cartridges of the respective 
embodiments, the erroneous recording prevention member is formed in such a 
manner that it is attached in the state inserted from the front portion 
side of the cartridge body, the erroneous recording prevention member may 
be attached from the principal surface side of the cartridge body. 
The fifth preferred embodiment in which the erroneous recording prevention 
member is attached from the principal surface side of the cartridge body 
will be described with reference to the attached drawings. 
It is to be noted that reference numerals are the same for the features 
common to those of the previously described first embodiment and detailed 
explanation thereof is omitted, and only certain illustrative features 
will be described. 
In the tape cartridge 401 of the fifth embodiment, similar to the 
previously described first embodiment, at the portion where an erroneous 
recording prevention member 437 is disposed of cover member 3, as shown in 
FIG. 27, a guide recessed portion 433 within which the erroneous recording 
prevention member 437 is moved and an erroneous recording detection hole 
432 opened or closed by the erroneous recording prevention member 437 are 
provided. 
The guide recessed portion 433 within which the erroneous recording 
prevention member 437 is disposed is formed extending over the front 
portion 25 of the cover member 3 which is formed on the front portion 2a 
of cartridge body 2 and top plate 30 of the cover member 3 opposite to the 
base plate 4 of the cartridge body 2. A bottom surface portion 434 of the 
guide recessed portion 433 serves as the portion held or clamped by the 
erroneous recording prevention member 437. This bottom surface portion 434 
is formed as a plate-shaped member parallel to the top plate 30 of the 
cover member 3 in such a manner that the erroneous recording prevention 
hole 432 is formed at the front 25 of the cover member 3. 
At the internal end side of the portion extending on the top plate 30 of 
the guide recessed portion 433, as described later, an insertion groove 
429 is formed into which an insertion piece 441 provided at the erroneous 
recording prevention member 437 is inserted. 
Moreover, at the inner surface side of the top plate 30 of the cover member 
3 opposite to the internal end of the guide recessed portion 433, an 
engagement recessed portion 436 is formed with which the insertion piece 
441 of the erroneous recording prevention member 437 is engaged. The part 
of the engagement recessed portion 436 formed of the top plate 30 serves 
as a pressing supporting portion 435 of the insertion portion 441. 
Further, within the engagement recessed portion 436, first and second 
holding recessed portions 443, 444 are provided which form the positioning 
mechanism such that when the erroneous recording prevention member 437 
disposed within the guide recessed portion 433 is moved to the first 
position where it closes the erroneous recording detection hole 432 shown 
in FIG. 30 and the second position where it opens the erroneous recording 
detection hole 432 as shown in FIG. 31, a holding projection 442 
projecting from the insertion piece 441 is engaged with the respective 
first and second holding recessed portions 443, 444, thus to provide 
positioning when moved to the first and second positions of the erroneous 
recording prevention member. 
At the bottom surface portion 434 of the guide recessed portion 433, as 
shown in FIG. 27, there is formed, as shown in FIG. 27, an engagement 
groove 451 with which an engagement projection 440 projecting from the 
lower surface of the base end side of a movement guide piece 439 of the 
erroneous recording prevention member 437 is engaged. This engagement 
groove 451 is formed as a penetrated cut groove in the bottom surface 
portion 434. Further, the engagement groove 451 is formed in parallel to 
the front portion 2a of the cartridge body 2 which is the movement 
direction of the erroneous recording prevention member 437. In addition, 
an insertion groove 452 is formed at the engagement groove 451 for 
allowing a holding pawl 440a to be inserted therethrough as a holding 
portion provided at the front end side of the engagement projection 440. 
This insertion groove 452 is obliquely formed with respect to the length 
direction of the engagement groove 451. 
Meanwhile, the erroneous recording detection hole 432 opened and closed by 
the erroneous recording prevention member 437 is provided at the front 
portion 25 of the cover member 3 positioned within the guide recessed 
portion 433. This erroneous recording detection hole 432 is provided at 
the position opposite to the detection element of the erroneous recording 
detection mechanism disposed at the recording/reproduction unit side when 
the tape cartridge 401 is loaded into the recording/reproduction unit. In 
addition, the erroneous recording detection hole 432 allows the detection 
element of the erroneous recording detection mechanism to project into the 
cartridge body 2. 
Further, the erroneous recording prevention member 437 attached to the 
cover member 3 and positioned within the guide recessed portion 433 
includes, at the base end portion side thereof, as shown in FIGS. 27 and 
28, a portion of a detection member (detected portion when viewed from the 
recording medium device) 438 for actuating the erroneous recording 
detection mechanism disposed at the recording/reproduction unit side, and 
a holding portion 445 for holding or clamping a bottom surface portion 434 
of the guide recessed portion 433 which is a portion of the cover member 3 
and is provided at the base end portion side including the portion of the 
detection member 438. This holding portion 445 is formed by a movement 
guide piece 439 serving as a movement guide portion projecting 
substantially vertically from the portion of the detection member 438 and 
extending toward the top plate 30 side portion of the guide recessed 
portion 433 and an engagement projection 440 engaged with the engagement 
groove 451 within the guide recessed portion 433 projecting from the lower 
surface side of the movement guide piece 439. Namely, as shown in FIG. 28, 
the holding portion 445 forms a channel-shaped portion of the movement 
guide piece 439 in cooperation with the engagement projection 440 provided 
with a holding pawl 440a at the front end portion thereof. 
At the front end side of the movement guide piece 439 of the erroneous 
recording prevention member 437, the insertion piece 441 projects 
therefrom such that when the erroneous recording prevention member 437 is 
attached to the cover member 3, the inserted piece 441 is inserted into an 
insertion groove 429 provided at the bottom surface portion 434 of the 
guide recessed portion 433 and is inserted toward the inner surface side 
of the top plate 30 of the cover member 3. This insertion piece 441 
projects from the lower end side of the front end side of the movement 
guide piece 439 and an offset portion 441a is formed on the upper surface 
of the continuously connecting portion side of the movement guide piece 
439. This offset portion 441a has a height substantially equal to the 
thickness of the pressing supporting portion 435 of the cover member 3 
side. 
At the upper surface side of the insertion piece 441, the holding 
projection 442 projects therefrom and is engaged with the first and second 
holding recessed portions 443, 444 formed within the engagement recessed 
portion 436 provided at the cover member 3 side. 
In order to attach the erroneous recording prevention member 437 designed 
as described above, the insertion piece 441 is inserted into the 
engagement recessed portion 436, and the holding pawl 440a provided at the 
front end side of the engagement projection 440 is disposed on a surface 
of the cartridge body 2 in a manner opposite to the insertion groove 452 
of the engagement groove 451. At this time, since the insertion groove 452 
is obliquely formed with respect to the engagement groove 451 in parallel 
to the front portion 2a of the cartridge body 2, the erroneous recording 
prevention member 437 is obliquely disposed with respect to the guide 
recessed portion 433 as shown in FIG. 29. When the engagement projection 
440 is caused to be passed through the engagement groove 451 to rotate the 
erroneous recording prevention member 437 in a manner such that it is 
parallel to the guide recessed portion 433, the holding pawl 440a holds 
the lower surface side of the bottom surface portion 434 as shown in FIG. 
28. As a result, the bottom surface portion 434 is clamped or held by the 
holding portion 445 formed by the engagement projection 440 and the 
movement guide piece 439. Thus, attachment with respect to the cartridge 
body 2 of the erroneous recording prevention member 434 is performed. 
When the erroneous recording prevention member 437 is attached in this way, 
the insertion piece 441 comes into pressure contact with the internal 
surface side of the cartridge body 2 while undergoing elastic 
displacement. In this case, elastic repulsive force of the insertion piece 
441 is applied in a manner to press the internal surface thereof onto the 
bottom surface portion 434 of the guide recessed portion 433 with respect 
to the movement guide piece 439 as reactive force. Thus, the bottom 
surface portion 434 of the guide recessed portion 433 is held or clamped 
by the movement guide piece 439 and the engagement projection 440, and the 
erroneous recording prevention member 437 is securely combined with the 
guide recessed portion 433 therewithin by the elastic repulsive force of 
the insertion piece 441 applied to the engagement projection 440. As a 
result, slipping off is prevented. 
In the condition where the erroneous recording prevention member 437 is 
attached to the guide recessed portion 433 by the above-described 
operation, the engagement projection 422 provided on the insertion piece 
441 is relatively engaged with any one of the first and second holding 
recessed portions 443, 444 provided within the engagement recessed portion 
436 as shown in FIGS. 30 and 31. The engagement state between the holding 
projection 442 and the holding recessed portions 434, 444 is securely held 
by elastic repulsive force of the insertion portion 441. At this time, the 
portion of the detection member 438 of the erroneous recording prevention 
member 437 is opposed to the front portion 25 of the cover member 3 where 
the erroneous recording detection hole 332 is formed as shown in FIG. 28. 
The erroneous recording prevention member 437 secured within the guide 
recessed portion 433 provided at the cover member 3 is moved in the 
direction indicated by arrow S and in the direction indicated by arrow T 
in FIGS. 30 and 31 along the front portion 2a of the cartridge body 2 
while the engagement projection 440 is guided by the engagement groove 451 
and the insertion piece 441 is guided by the engagement recessed portion 
436. When the erroneous recording prevention member 437 is moved from the 
first position shown in FIG. 30 to the second position shown in FIG. 31, 
or from the second position shown in FIG. 31 to the first position shown 
in FIG. 30, the insertion portion 441 is caused to undergo elastic 
displacement in the thickness direction thereof. As a result, the holding 
projection 441 engaged with the first or second holding recessed portion 
443 or 444 is moved riding on the bottom surface of the engagement 
recessed portion 436. When the erroneous recording prevention member 437 
is moved to the first or second position, the holding projection 441 is 
relatively engaged with the first or second holding recessed portion 443 
or 444, and is held at the first or second position. Thus, the erroneous 
recording prevention member 437 is securely held at the first or second 
position. 
Moreover, at the lower edge portion positioned at the front portion 25 of 
the cover member 3 of the guide recessed portion 433, a position limiting 
projection 451 projects therefrom such that when the erroneous recording 
prevention member 437 is moved to the first or second position, the 
position limiting projection 451 is held on the side surface of the 
portion of the detection member 438 to limit the movement position of the 
erroneous recording prevention member 437. As the result, the erroneous 
recording prevention member 437 is more securely held at the first or 
second position by the position limiting mechanism formed of the holding 
projection 441 and the first or second holding recessed portion 443 or 444 
with which the holding projection 451 is engaged. 
Meanwhile, in the tape cartridge 401 of this embodiment, when the erroneous 
recording prevention member 437 is moved to (or located at) the first 
position as shown in FIG. 30 to one side of the cartridge body 2 where the 
portion of the detection member 438 closes the erroneous recording 
detection hole 432 provided at the front portion 25 of the cover member 3, 
recording of information signals can be made with respect to the magnetic 
tape 12 accommodated within the cartridge body 2. In addition, when the 
erroneous recording prevention member 437 is moved in the direction 
indicated by arrow T in FIG. 30 from the first position shown in FIG. 30 
to the second position where the portion of the detection member 438 opens 
the erroneous recording detection hole 432 as shown in FIG. 31, recording 
of information signals with respect to the magnetic tape 12 accommodated 
within the cartridge body 2 is not permitted to be performed. 
Namely, in the recording/reproduction unit into which the tape cartridge 
401 of this embodiment is loaded, a detection mechanism is provided for 
detecting the portion of the detection member 438 of the erroneous 
recording prevention member 437. When the portion of the detection member 
438 is detected by the detection mechanism of the recording/reproduction 
unit (apparatus), selection of the recording operation mode for permitting 
recording of information signals with respect to the magnetic tape 12 can 
be determined. When detection of the portion of the detection member 438 
is not carried out by the detection mechanism, selection of the recording 
operation mode is impossible. 
While, in this embodiment, the erroneous recording detection hole 432 is 
formed so as to have a width extending over the range of the guide 
recessed portion 433 where the erroneous recording prevention member 437 
is disposed, it is sufficient to provide an erroneous recording detection 
hole 432 formed only at a portion opposed to the detection mechanism of 
the recording/reproduction unit. Namely, the erroneous recording 
prevention member 437 may be formed so as to have a size (dimensions) 
covered by the portion of the detection member 438 when it is moved to the 
first position as shown in FIG. 30. 
While, in the above-described tape cartridges of the respective 
embodiments, the erroneous recording detection hole is positioned within 
the guide recessed portion provided at the cover member to be opened at 
the front portion thereof, it may, however be positioned at any surface 
position thereof and opened thereat. In this case, in the erroneous 
recording prevention member, e.g., a portion of the base end portion side 
of the movement guide piece is also designed as a portion of the detection 
member. 
In addition, this invention is not limited to the tape cartridges in which 
magnetic tape is accommodated within the cartridge body, but also may be 
applied to disc cartridges in which disc-shaped recording medium such as 
optical disc or magneto-optical disc, etc. is rotatably accommodated 
within the cartridge body. In this situation, advantages similar to the 
previously described advantages will be attained. 
In the recording medium device according this invention, the erroneous 
recording prevention member is attached to the cartridge body so that the 
portion of the detection member can be moved within the range between the 
first position and the second position. This erroneous recording 
prevention member is secured in the first and the second position by 
holding or clamping a portion of the cartridge body by the holding portion 
provided at the base end portion side where the portion of the detection 
member is provided and inserting the insertion portion provided at the 
front end side of the holding portion toward the interior of the cartridge 
body. Accordingly, easy withdrawal from the cartridge body is prevented. 
Thus, the erroneous recording prevention member is moved within the range 
between the first position and the second position in a stable state. 
Particularly, since the erroneous recording prevention member is attached 
to the cartridge body so that the insertion portion is inserted into the 
cartridge body such that repulsive forces come into pressure contact with 
the inner surface side of the cartridge body, the erroneous recording 
prevention member is attached so that it is elastically held with respect 
to the cartridge body by the holding portion and the insertion portion. 
Thus, a firm attachment state of the erroneous recording prevention member 
is attained. 
While the present invention has been particularly shown and described with 
reference to certain preferred embodiments, it will be readily apparent to 
those of ordinary skill in the art that various changes and modifications 
may be made therein without departing form the spirit and scope of this 
invention. It is intended that the appended claims be interpreted as 
including the foregoing as well as various other such changes and 
modifications.