JPH0536153A - Tape cassette and magnetic tape end detector - Google Patents

Abstract

PURPOSE:To detect an end part of a magnetic tape wound around a cylindrical hub by a light signal giving and receiving means using one pair of a light emitting element and a light receiving element. CONSTITUTION:An outer circumferential surface 8c1 of a hub 8c of a supply reel 8 and an outer circumferential surface 9c1 of a hub 9c of a take-up reel 9 are formed with a specular and high reflecting surface having higher reflectance than the magnetic tape 7. Then, the light emitting element 11 and the light receiving element 12 to be the light signal giving and receiving means are disposed in an opening part 6 of a tape cassette 1 loaded into a magnetic recording and/or reproducing device. On the other hand, the outer circumferential surfaces 8c1 and 9c1 of the hubs 8c and 9c are fixed with the end part of the magnetic tape 7, and when parts of the outer circumferential surfaces 8c1 and 9c1, which is not wound with the magnetic tape 7 by traveling movement of the magnetic tape 7, are irradiated with light from the light emitting element 11, this light is refelcted to be received by the light receiving element 14. By this method, the end part of the magnetic tape 7 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette and a magnetic tape end detection for detecting the end of a magnetic tape wound around a cylindrical hub by an optical signal transmitting / receiving means using a pair of a light emitting element and a light receiving element. It relates to the device.

[0002]

2. Description of the Related Art A video tape recorder (VTR),
Conventionally, there is a magnetic tape end detecting device used in a magnetic recording and / or reproducing apparatus such as a digital audio tape recorder (DAT) as shown in FIG.

In this magnetic tape end detecting device 100, the tape cassette 101 is composed of upper and lower halves 101a and 101b.
It is assembled in a box shape by (only the lower half 101b is shown), and the magnetic tape 104 is provided on the supply reel 102 and the take-up reel 103 provided in the tape cassette 101.
Is wound. A transparent leader tape 105a is connected to the ends (starting end and end) of the magnetic tape 104, that is, the starting end of the magnetic tape 104, and is wound around the take-up reel 103. A transparent leader tape 105b is connected to the end portion and wound around the supply reel 102.

When the tape cassette 101 is mounted on a VTR, DAT, etc., not shown, the tape cassette 1
The front lid 106 of 01 (shown by a chain double-dashed line) is opened, and the magnetic tape 104 is loaded into the VTR and DAT.
At this time, a light emitting element 107 such as a lamp is inserted into the hole 101b ₁ formed in the lower half 101b of the tape cassette 101, and the light emitted from the light emitting element 107 is formed in the holes formed on both left and right sides of the lower half 101b. 101b ₂ , 101
After passing through b ₃ , the light is received by the light receiving elements 108 a and 108 b such as CdS installed on the left and right sides of the lower half 101 b. In this case, the magnetic tape 104 is pulled out of the tape cassette 101 and run, and the magnetic tape 104 is run in the tape cassette 101 without being pulled out, the gap between the light emitting element 107 and the light receiving elements 108a and 108b is set. Passing magnetic tape 104
Does not transmit the light from the light emitting element 107, while the transparent leader tapes 105a and 105b connected to the start end and the end of the magnetic tape 104 transmit the light from the light emitting element 107. It is possible to detect that it is (the starting end portion and the terminating end portion).

[0005]

By the way, in the conventional magnetic tape edge detecting device 100 shown in FIG.
07 and the light-receiving elements 108a and 108b, the transparent leader tapes 105a and 105b can be detected to detect the end portions (start end portion and end portion) of the magnetic tape 104. The transparent leader tapes 105a and 105b must be connected to the start end portion and the end portion of the magnetic tape 104 without fail, which increases the number of work steps when manufacturing the magnetic tape 104, and the transparent leader tape 105.
Material costs for a and 105b are also high, which prevents the tape cassette 101 housing the magnetic tape 104 from being provided to consumers at low cost. Further, since the connecting points between the magnetic tape 104 and the transparent leader tapes 105a and 105b are connected by an adhesive material, there is also a problem that the magnetic tape 104 and the transparent leader tapes 105a and 105a are separated from each other due to a change with time of the adhesive material. Has occurred.

Further, the light from the light emitting element 107 receives light from the light receiving elements 108a, 108a provided on both left and right sides of the lower half 101b.
Although the light is received by b, when the tape cassette 101 is adopted in a magnetic recording and / or reproducing device such as a newly designed VTR or DAT, the light emitting element 107 and the light receiving element 108 are used.
Since the installation positions of a and 108b are limited, the degree of freedom in design is lost and it is inconvenient when the device is downsized.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the first invention is to wind the magnetic tape by fixing the end of the magnetic tape to a cylindrical hub. In a tape cassette in which the end portion of the magnetic tape is detected by an optical signal transmitting / receiving unit using a pair of light emitting element and light receiving element provided in the magnetic recording and / or reproducing apparatus, In the tape cassette, the outer peripheral surface of the hub is formed as a highly reflective surface having a higher reflectance than the magnetic tape.

According to a second aspect of the present invention, the tape cassette according to the first aspect is mounted on a magnetic recording and / or reproducing device, and a pair of light emitting element and light receiving element serving as an optical signal transmitting / receiving means are cylindrical in the apparatus. Is provided outside the winding of the magnetic tape wound around the hub, and the light emitted from the light emitting element is applied to the outer peripheral surface of the hub, and the magnetic field is on the optical path until the light is received by the light receiving element. When the outer peripheral surface portion of the hub that does not wind the magnetic tape reaches the end portion of the magnetic tape due to the running operation of the magnetic tape, the tape emits light from the light emitting element. The outer peripheral surface portion of the hub where the magnetic tape is not wound is irradiated with the generated light, and the light reflected here is received by the light receiving element to detect the end portion of the magnetic tape. Characterized by A magnetic tape end detection device that.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tape cassette and a magnetic tape end detecting device according to the present invention will be described below in detail in the order of <tape cassette> and <magnetic tape end detecting device> with reference to FIGS. To do.

The technical idea of the tape cassette and the magnetic tape end detecting device according to the present invention is to form a magnetic tape by forming the outer peripheral surface of a cylindrical hub on a mirror-like high reflection surface having a higher reflectance than the magnetic tape. When the tape is wound around the hub, the end of the magnetic tape is not attached to the end (starting end or end) of the magnetic tape in the tape cassette without connecting the transparent leader tape described in the conventional example. A tape cassette is formed by directly fixing and winding the tape cassette, and further, a pair of light emitting element and light receiving element are provided in the magnetic recording and / or reproducing apparatus, and the tape cassette is mounted on the magnetic recording and / or reproducing apparatus. When the outer peripheral surface of the hub on which the magnetic tape is not wound reaches the end of the magnetic tape due to the running operation of the magnetic tape, the light emitted from the light emitting element is not wound on the magnetic tape. Irradiating the outer peripheral surface portion of the, which is constituted so as to detect that the light reflected here is an end of a magnetic tape received by the light receiving element.

<Tape Cassette> FIG. 1 is an external perspective view showing the tape cassette according to the present invention as seen from the lower side, and FIG. 2 is a vertical sectional view showing the tape cassette according to the present invention.

As shown in FIG. 1, a tape cassette 1 according to the present invention comprises a video tape recorder (VTR),
The tape cassette 1 is used for magnetic recording and / or reproducing equipment (not shown) such as a digital audio tape recorder (DAT), and the outer frame of the tape cassette 1 is made of a resin material or the like. 3 and 3 are combined to form a rectangular box body.

The surface 2a of the lower half 2 is the lower surface side when it is mounted in the device, and the lower surface 2a is provided with holes 2a ₁ and 2a ₂ facing a pair of reels 8 and 9 described below. are holes 2a ₃ is bored in the light-emitting element is inserted as shown further in the prior art between the holes 2a _1, 2a _2. A lid 4 is provided on the front side in the figure so as to be openable and closable in the direction of the arrow around the shaft 5. The opening 6 near the lid 4 in the drawing is a portion into which a magnetic tape loading member (not shown) in the magnetic recording and / or reproducing apparatus is inserted.

A pair of reels 8 and 9 around which the magnetic tape 7 is wound are rotatably provided in the tape cassette 1, where 8 is a supply reel and 9 is a take-up reel.

Now, the structures of the supply reel 8 and the take-up reel 9 described above will be described with reference to FIG. Since the supply reel 8 and the take-up reel 9 are formed in the same structure, the structure on the supply reel 8 side will be mainly described.
The take-up reel 9 side will be described with the same auxiliary reference numerals as necessary.

As shown in FIG. 2, the structure of the supply reel 8 is integrally composed of a disk-shaped upper flange 8a, a lower flange 8b having the same shape, and a cylindrical hub 8c. It is formed in a "V" shape using a resin material or the like.
That is, the upper flange 8a and the lower flange 8b are opposed to each other, and the central portion of the upper flange 8a and the lower flange 8a are
A hub 8c is vertically provided between the central portion of b and the hub 8c, and these are integrally formed into a "V" shape by press fitting.
The structure of the supply reel 8 includes upper and lower flanges 8a,
8b may be omitted and only the cylindrical hub 8c may be formed. Similarly, the take-up reel 9 also has the cylindrical hub 9c.
Alternatively, the magnetic tape 7 may be wound around the hubs 8c and 9c.

The magnetic tape 7 is wound around the hub 8c of the supply reel 8 and the hub 9c of the take-up reel 9, and before the magnetic tape 7 is mounted on a magnetic recording and / or reproducing apparatus, the supply reel 8 is used.
Magnetic tape 7 wound around the lid 4 that can be freely opened and closed (Fig. 1)
It is wound on the take-up reel 9 along the vicinity of.
The lid 4 side is the front surface in the insertion direction of the tape cassette 1.

The end (starting end or end) of the magnetic tape 7 wound around the supply reel 8 and the take-up reel 9 is
The transparent leader tape described in the conventional example is not connected, but the end portion of the magnetic tape 7 is directly fixed to the outer peripheral surface 8c ₁ of the hub 8c and the outer peripheral surface 9c ₁ of the hub 9c. The method of fixing the end portion of the magnetic tape 7 is such that it is sandwiched by the clampers 8c ₃ and 9c ₃ shown in FIG. 3, or slits are formed in the outer peripheral surface 8c ₁ and the outer peripheral surface 9c ₁ and then adhered after sandwiching. The way is done.

[0019] Here, the outer peripheral surface 9c of the hub 9c of the outer circumferential surface 8c ₁ and a take-up reel 9 of the hub 8c of the supply reel 8
₁ is a part of the essential part of the present invention. That is,
The outer circumferential surface 9c of the outer circumferential surface 8c ₁ and the hub 9c of the hub 8c
₁ is formed over the entire circumference on a mirror-like high reflection surface having a higher reflectance than the magnetic tape 7, and the light emitted from a light emitting element 11 (FIG. 4) of the optical signal transmitting / receiving means described later has an outer peripheral surface 8c _1. When the outer peripheral surface 9c ₁ is irradiated with the light, the light is reflected here so that the light receiving element 12 (FIG. 4) can surely receive the light. That is, the outer peripheral surface 8c ₁ of the hub 8c and the hub 9c
For the outer peripheral surface 9c ₁ of the
Alternatively, a metal such as aluminum is vapor-deposited to form a high-reflectance film, which is formed on a mirror-like high-reflectance surface having a higher reflectance than the magnetic tape 7.

At the center of the hub 8c of the supply reel 8 and the center of the hub 9c of the take-up reel 9, a supply reel drive unit 14 (FIG. 4) in a magnetic recording and / or reproducing device (not shown) is provided. and a take-up reel drive unit 15 (FIG. 4) and has engagement holes _8c 2, 9c ₂ which engages is drilled, these engaging holes _8c 2, 9c ₂ is hole of the lower surface 2a of the lower half 2 2
It faces a ₁ and 2 a ₂ .

<Magnetic Tape Edge Detecting Device> FIG. 3 is a plan view showing a magnetic tape edge detecting device according to the present invention, and FIG. 4 is a view showing the magnetic tape edge detecting device X--O--X, Y shown in FIG. −
It is a longitudinal cross-sectional view taken along the line OY. FIG. 5 is a vertical cross-sectional view showing a modified example of the magnetic tape edge detecting device.

A magnetic tape end detecting device 10 according to the present invention using the above-mentioned tape cassette 1 will be described with reference to FIGS. 3 and 4.

In the magnetic tape end detecting apparatus 10 according to the present invention shown in FIG. 3, the tape cassette 1 is used for magnetic recording and / or recording.
Alternatively, it is mounted at a predetermined mounting position of a playback device (not shown). Then, in the tape cassette 1, the end portion of the magnetic tape 7, that is, the end portion is clamped by the clamper 8c _{3 on} the outer peripheral surface 8c ₁ of the hub 8c of the supply reel 8 and then wound several times. . Then, the magnetic tape 7 wound around the supply reel 8 passes through the opened lid 4 and is loaded onto the outside of the tape cassette 1, and again from the lid 4 the outer peripheral surface 9c of the hub 9c of the winding reel 9 inside. wound ₁ wound, and the ends of the take-up reel 9 side of the magnetic tape 7, i.e., all the time the end portion is wound after being clamped by the clamper 9c _3.

Further, the light emitting element 11 (11A, 11B) and the light receiving element 12 of the optical signal transmitting / receiving means, which are a part of the essential part of the present invention, are provided at appropriate positions in the opening 6 on the lid 4 side.
(12A, 12B) are inserted at the positions shown, and the light emitting element 11 (11A, 11B) and the light receiving element 12 are also inserted.
(12A, 12B) are installed in the chassis 13 (FIG. 4) of the magnetic recording and / or reproducing device. Of the above, the light emitting element 11A and the light receiving element 12A are provided as a pair of optical signal transmitting / receiving means on the supply reel 8 side by side, and on the other hand,
A pair of the light emitting element 11B and the light receiving element 12B are provided adjacent to each other as an optical signal transmitting / receiving means on the take-up reel 9 side.

Further, the light emitting device 1 installed in the opening 6
1 (11A, 11B) and light receiving element 12 (12A, 12B)
B) is provided outside the maximum winding diameter of the magnetic tape 7 wound around the hub 8c of the supply reel 8 and outside the maximum winding diameter of the magnetic tape 7 wound around the hub 9c of the take-up reel 9. In addition, the light path when the light emitted from the light emitting element 11 is reflected and received by the light receiving element 12 as described later, here, the heights of the light emitting element 11 and the light receiving element 12 are as shown in FIG. Since they are installed at the same height from the chassis 13, the optical path is formed in the horizontal plane. Further, the magnetic tape 7 is always present on the optical path until the light emitted from the light emitting element 11 is applied to the outer peripheral surface 8c ₁ of the hub 8c and the outer peripheral surface 9c ₁ of the hub 9c and the light is received by the light receiving element 12. It is provided to do.

When the upper and lower flanges 8a and 8b of the supply reel 8 and the upper and lower flanges 9a and 9b of the take-up reel 9 are not provided as described above, the light emitting element 11 and the light receiving element 12 are wound on the magnetic tape 7. It can be installed at an appropriate position in the supination.

Further, the light emitting element 11 and the light receiving element 12 are constituted by general photosensors, and the kinds of parts of the light emitting element 11 and the light receiving element 12 are not particularly limited, but as a light source of the light emitting element 11. A lamp or a light-emitting body (LED, EL, etc.) is used for. Further, as the light from the light emitting element 11, visible light or infrared light is used.

Further, the light emitting element 11 is pulse-modulated and received by the light receiving element 12, and the synchronized state of the received light and the light from the light emitting element 11 is compared with the level and the like to accurately distinguish it from the external light. Although a method can be adopted, detailed description thereof will be omitted here.

If a thin magnetic tape 7 is used and the light from the light emitting element 11 is semi-transmitted through the magnetic tape 7 and may be erroneously detected by the light receiving element 12, the light from the light emitting element 11 may be detected. Various methods such as controlling the intensity of light, appropriately selecting the wavelength of light of the light emitting element 11, or including a large amount of a composition for preventing light transmission in the magnetic layer of the magnetic tape 7. Therefore, the detection accuracy is further improved.

Further, as shown in FIG. 4, the supply reel drive section 14 and the take-up reel drive section 15 are engaged with the engagement hole 8c ₂ of the supply reel 8 and the engagement hole 9c ₂ of the take-up reel 9, respectively. Thus, the running operation of the magnetic tape 7 is possible.

The magnetic tape end detecting operation of the magnetic tape end detecting device 10 according to the present invention will be described with reference to FIG. In FIG. 4, X-O-X and Y-O in FIG.
Although illustrated along −Y, the light receiving element 12 adjacent to the light emitting element 11 is illustrated by a chain double-dashed line.

Further, as described above, the outer peripheral surface 8c ₁ of the hub 8c of the supply reel 8 and the outer peripheral surface 9c ₁ of the hub 9c of the take-up reel 9 are mirror-like highly reflective surfaces having a higher reflectance than the magnetic tape 7. It is assumed that it is formed over the entire circumference.

In the magnetic tape end detection operation of the magnetic tape end detection device 10 shown in FIG. 4, the end portion of the magnetic tape 7 on the supply reel 8 side and the start end portion of the magnetic tape 7 on the take-up reel 9 side are set to the magnetic tape 11. It is to be detected as the end of. Of course, this magnetic tape end detecting operation is performed during the running operation of the magnetic tape 7 such as during the running or stop of the magnetic tape 11.

The magnetic tape end detecting operation will be described step by step. As described above, the transparent leader tape described in the conventional example is not connected to the start end and the end of the magnetic tape 7, but from the supply reel 8 side. In the state before the magnetic tape 7 is sent to the take-up reel 9 side, the starting end of the magnetic tape 7 is directly clamped and fixed to the outer peripheral surface 9c ₁ of the hub 9c of the take-up reel 9, In this state, the outer peripheral surface 9c ₁ portion of the hub 9c that has not been wound has also appeared. Here, the light from the light emitting element 11B on the take-up reel 9 side travels straight and travels to the outer peripheral surface 9 of the hub 9c of the take-up reel 9.
directed to c _1, particularly when the magnetic tape 7 is irradiated to the outer peripheral surface 9c ₁ portion not wound is an outer peripheral surface the light is formed in a mirror-like highly reflective surface having high reflectance than the magnetic tape 7 The light is reflected by 9c ₁ and this light is further emitted from the light emitting element 11B.
The light is received by the light-receiving element 12B installed next to. Thereafter, the output from the light receiving element 12B is detected by the light receiving amount comparison circuit means (not shown) as the starting end portion of the magnetic tape 7, that is, the end portion on the take-up reel 9 side.

On the other hand, on the supply reel 8 side, the magnetic tape 7 is wound many times after the end portion of the magnetic tape 7 is clamped by the outer peripheral surface 8c ₁ of the hub 8c of the supply reel 8. Light from the light emitting element 11A on the reel 8 side is blocked by the magnetic tape 7, and the outer peripheral surface 8c _{1 of the} hub hub 8c
Therefore, a very small part of the return light from the light emitting element 11A is diffusely reflected from the magnetic tape 7 and is received by the light receiving element 12A.
Although it reaches A, the amount of reflection is weak, so the light receiving element 12
In A, after receiving light, the light receiving amount comparison circuit means (not shown) does not detect that the supply reel 8 side is the end portion (end portion) of the magnetic tape 7.

After that, the supply reel drive unit 14 on the supply reel 8 side and the take-up reel drive unit 15 on the take-up reel 9 side.
When the magnetic tape 7 is driven by the magnetic tape 7 and all of the magnetic tape 7 wound on the supply reel 8 is wound on the take-up reel 9, this time is completely opposite to the above. Therefore, the outer peripheral surface of the hub 8c of the supply reel 8 is On 8c ₁ , a portion where the end portion of the magnetic tape 7 is sandwiched and an outer peripheral surface 8c ₁ portion where the magnetic tape 7 is not wound appear. Here, when light from the light emitting element 11A is irradiated to the outer peripheral surface 8c ₁ portion not wound magnetic tape 7, the light is received by the light receiving element 12A is reflected, the end of the magnetic tape 7, namely , It is detected to be the end portion, while on the winding reel 9 side, the end portion (starting end portion) is not detected because it is blocked by the magnetic tape 7.

Next, the light emitting element 11 (11 shown in FIG.
FIG. 5 shows a modified example as an example in which the A, 11B) and the light receiving elements 12 (12A, 12B) are installed at positions different from those in the above horizontal plane.

In the magnetic tape end detecting device 20 shown in FIG. 5, the light emitting element 11 and the light receiving element 12 are provided in the hole 2 of the lower half 2.
It was inserted into a _3, and, the light emitting element 11A and a light receiving element 12
A, the light emitting element 11B, and the light receiving element 12B are installed in the height direction vertically as shown in the drawing. Even in this case, the tape end detecting operation of the magnetic tape end detecting device 20 is the same as that described above, and the description thereof is omitted here.

Further, when the lower half 2 and the upper half 3 of the tape cassette 1 are formed of members that transmit the light from the light emitting element 13, the tape cassette 1 is provided outside the tape cassette 1 along the side surface with the supply reel 8 side. There is also a method of installing the light emitting element 11 and the light receiving element 12 at appropriate positions corresponding to the take-up reel 9 side.

Although not described in detail here, even if the transparent leader tape explained in the conventional example is connected to the end of the magnetic tape 7, if the hubs 8c and 9c which are the essential parts of the present invention are used. Similar to the above, the end of the magnetic tape 7 can be detected without any trouble.

Further, in the embodiment, the tape cassette 1 is provided with the pair of reels 8 and 9, but the present invention is not limited to this, and a tape cassette including a single reel or a single hub may be used. good. In the case of this configuration, the starting end of the magnetic tape 7 is sent to the winding side of the magnetic recording and / or reproducing device by the loading means (not shown) and is wound up. The end portion is fixed to the hub 8c and then wound. In this case, the end of the magnetic tape 7,
That is, the end portion can be detected by the optical signal transmitting / receiving means using the pair of the light emitting element 11A and the light receiving element 12A.

As described above in detail, in the tape cassette 1 and the magnetic tape end detecting devices 10 and 20 of the present invention, the conventional work of connecting the transparent leader tape to the end of the magnetic tape 7 is eliminated, and the magnetic tape 7 is eliminated. It is possible to provide the tape cassette 1 containing the tape to the consumer at low cost. In addition, since the adhesive material for connecting the transparent leader tape is not required and the adhesive material does not change with time, the magnetic tape 7
The advantage is that the reliability and quality of the tape cassette 1 accommodating the tape are significantly improved.

Further, in the magnetic recording and / or reproducing apparatus, the pair of the light emitting element 11 and the light receiving element 12 can be freely installed inside and outside the tape cassette 1 in a space efficient manner. Freedom increased,
It becomes possible to reduce the size of the device.

[0044]

According to the tape cassette and the magnetic tape end detecting device according to the present invention described in detail above, in the tape cassette according to claim 1, the end portion of the magnetic tape in the tape cassette is as described in the conventional example. Without connecting a transparent leader tape, the end of the magnetic tape is fixed to a cylindrical hub and then wound, and the outer peripheral surface of the hub is formed into a mirror-like highly reflective surface with higher reflectance than the magnetic tape. Thus, the end of the magnetic tape can be detected by the optical signal transmitting / receiving means using a pair of light emitting element and light receiving element provided in the magnetic recording and / or reproducing device. This eliminates the conventional work of connecting the transparent leader tape to the end of the magnetic tape in the tape cassette, and makes it possible to provide the tape cassette containing the magnetic tape to consumers at low cost. Further, since the adhesive material for connecting the transparent leader tape is not required and the adhesive material does not change over time, there is an advantage that the reliability and quality of the tape cassette accommodating the magnetic tape are significantly improved.

Further, in the magnetic tape end detecting device according to the second aspect, the tape cassette according to the first aspect is mounted in the magnetic recording and / or reproducing device, and the magnetic tape is moved to the end part of the magnetic tape by the running operation. When the outer peripheral surface of the unwound hub appears, the light from the light emitting element is applied to the outer peripheral surface of the hub on which the magnetic tape is not wound, and the light reflected here is received by the light receiving element. , The end of the magnetic tape is detected. At this time, in the magnetic recording and / or reproducing apparatus, a pair of light emitting element and light receiving element can be freely installed inside and outside the tape cassette in a space-efficient manner, which increases flexibility in designing the magnetic recording and / or reproducing apparatus. Therefore, it becomes possible to realize miniaturization of the device.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a tape cassette according to the present invention as viewed from the lower surface side.

FIG. 2 is a vertical sectional view showing a tape cassette according to the present invention.

FIG. 3 is a plan view showing a magnetic tape edge detecting device according to the present invention.

FIG. 4 is a vertical cross-sectional view of the magnetic tape edge detecting device according to the present invention taken along the line X-O-X and Y-O-Y shown in FIG.

FIG. 5 is a vertical sectional view showing a modified example of the magnetic tape edge detecting device according to the present invention.

FIG. 6 is a diagram showing a configuration of a conventional magnetic tape edge detection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Tape cassette, 7 ... Magnetic tape, 8 ... Supply reel, 8c ... Hub, 8c ₁ ... Outer peripheral surface, 9 ... Take-up reel,
9c ... Hub, 9c ₁ ... Outer peripheral surface, 10 ... Magnetic tape end detection device, 11 (11A, 11B) ... Light emitting element, 12 (12
A, 12B) ... Light receiving element, 20 ... Magnetic tape end detecting device.

Claims (2)

[Claims] 1. A pair of light-emitting elements provided in a magnetic recording and / or reproducing apparatus when the end portion of the magnetic tape is fixed to a cylindrical hub and the magnetic tape is wound. And a tape cassette in which an end portion of the magnetic tape is detected by an optical signal transmitting / receiving means using a light receiving element, wherein the outer peripheral surface of the hub is formed as a highly reflective surface having a higher reflectance than the magnetic tape. Tape cassette. 2. The tape cassette according to claim 1 is mounted in a magnetic recording and / or reproducing device, and a pair of a light emitting element and a light receiving element, which are optical signal transmitting / receiving means, are wound in a cylindrical hub in the apparatus. The magnetic tape is provided outside the winding of the magnetic tape, and the light emitted from the light emitting element is applied to the outer peripheral surface of the hub, and the magnetic tape is interposed on the optical path until the light is received by the light receiving element. When the outer peripheral surface portion of the hub where the magnetic tape is not wound reaches the end portion of the magnetic tape due to the running operation of the magnetic tape, the light emitted from the light emitting element is emitted from the magnetic tape. The outer peripheral surface portion of the hub that is not wound, and the light reflected here is received by the light receiving element to detect the end portion of the magnetic tape. Tape edge inspection Output device.