JPH04344355A - Cassette tape and magnetic tape end detector - Google Patents

Abstract

PURPOSE:To detect the end of a magnetic tape wound on a hub by light signal transmitting/receiving means formed by using a pair of light emitting elements and light receiving elements. CONSTITUTION:A light transmission part 7b is formed along the outer peripheral surface 7a of the hub 7 by using a transparent member allowing the transmission of the light from the light emitting elements 13. Further, 1st and 2nd reflection surfaces 7c, 7d are formed on both sides of the transparent member within this light transmission part 7b. A pair of the light emitting elements 13 and the light receiving elements 14 which are the light signal transmitting/receiving means are inserted into the hole 2b of the lower half 2 of a tape cassette 1A. On the other hand, the end of the magnetic tape 11 is fixed to the outer peripheral surface 7a of the hub 7. Incident light is emitted from the outer peripheral surface via the 1st and 2nd reflection surfaces 7c, 7d and is received in the light receiving elements 14 when the light from the light emitting elements 13 is made incident on the outer peripheral surface part of the light transmission part 7b where the magnetic tape 11 is not wound. The end of the magnetic tape 11 is thus detected.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a tape cassette and a magnetic tape end detection device for detecting the end of a magnetic tape wound around a hub by means of optical signal transmission and reception using a pair of light emitting elements and light receiving elements. be.

0002

[Prior Art] Video tape recorder (VTR),
2. Description of the Related Art Conventionally, there is a magnetic tape edge detection device as shown in FIG. 4, which is employed in a magnetic recording/reproducing device such as a digital audio tape recorder (DAT).

In this magnetic tape end detection device, a tape cassette 101 is assembled into a box shape with upper and lower halves 101a and 101b (only the lower half 101b is shown).
Supply reel 102 provided inside this tape cassette 101
A magnetic tape 104 is wound around a take-up reel 103 and a take-up reel 103 . Further, a transparent leader tape 105a is connected to the ends (starting end and ending end) of the magnetic tape 104, that is, the starting end side of the magnetic tape 104, and the take-up reel 10
On the other hand, a transparent leader tape 105b is connected to the terminal end side of the magnetic tape 104 and wound around the supply reel 102.

Furthermore, when the tape cassette 101 is attached to a VTR, DAT, etc. (not shown), the tape cassette 1
The front cover 106 (shown by the two-dot chain line) of 01 is opened, and the magnetic tape 104 is loaded into the VTR or DAT. At this time, a light emitting element 107 such as a lamp is inserted into a hole 101b1 made in the lower half 101b of the tape cassette 101, and the light from this light emitting element 107 is transmitted to the lower half 101b.
The light passes through holes 101b2 and 101b3 drilled on both the left and right sides of the lower half 101b, and is received by light receiving elements 108a and 108b, such as CdS, installed on the outer sides of the lower half 101b on both the left and right sides. Here, in both cases where the magnetic tape 104 is pulled out from the tape cassette 101 and made to run, and when it is made to run within the tape cassette 101 without being pulled out, the light emitting element 107 and the light receiving element 108
The magnetic tape 104 passing between the magnetic tape 108a and 108b does not transmit the light from the light emitting element 107;
Transparent leader tape 10 connected to the starting end and ending end of 4
5a and 105b transmit the light from the light emitting element 107, so that it is possible to detect the ends (starting end and ending end) of the magnetic tape 104.

[0005]

By the way, the conventional magnetic tape edge detection device shown in FIG. magnetic tape 10
Although it is possible to detect the ends (starting end and ending end) of the magnetic tape 104, it is necessary to connect the transparent leader tapes 105a and 105b to the starting end and ending end of the magnetic tape 104. 104, the number of work steps increases, and transparent leader tapes 105a, 10
5b is also expensive, which prevents the tape cassette 101 containing the magnetic tape 104 from being provided to consumers at a low cost. Furthermore, since the connection points between the magnetic tape 104 and the transparent leader tapes 105a and 105b are connected by an adhesive, there is also the problem that the adhesive between the magnetic tape 104 and the transparent leader tapes 105a and 105a may peel off due to changes in the adhesive over time. It is occurring.

Furthermore, the light from the light emitting element 107 passes through light receiving elements 108a and 108 provided on both the left and right sides of the lower half 101b.
However, if this tape cassette 101 is adopted in a newly designed magnetic recording/reproducing device such as a VTR or DAT, the light emitting element 107 and the light receiving elements 108a and 108
This limits the installation position of b, which results in a loss of freedom in design and is inconvenient when downsizing the magnetic recording/reproducing device.

[0007]

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned problems, and the first invention is to fix an end of a magnetic tape to a cylindrical hub and wind the magnetic tape. In the tape cassette, when the tape cassette is attached to a magnetic recording/reproducing apparatus, the end of the magnetic tape is detected by an optical signal transmitting/receiving means using a pair of light emitting elements and light receiving elements provided in the magnetic recording/reproducing apparatus. A light transmitting portion is formed using a member that transmits light from the light emitting element in at least a part of the circumferential direction near the outer peripheral surface of the hub to form the hub into a cylindrical shape, and light is transmitted into the light transmitting portion. First and second reflective surfaces are formed with a transmitting member sandwiched therebetween, and the light from the light emitting element incident on the outer peripheral surface of the light transmitting portion is reflected from the first reflective surface.
The tape cassette is characterized in that the light is directed through a second reflective surface, is emitted from the outer circumferential surface of the light transmitting portion, and is received by the light receiving element.

A second aspect of the invention is to detect the end of the magnetic tape wound around the hub by using the tape cassette according to claim 1 and using an optical signal transmitting/receiving means using a pair of light emitting elements and light receiving elements. The magnetic tape edge detection device is such that light from the light emitting element is incident on the outer circumferential surface of the light transmitting section, and the incident light is directed to the outer circumferential surface of the light transmitting section via the first and second reflective surfaces. is emitted from the light receiving element and received by the light receiving element,
The light-emitting element and the light-receiving element are provided so that the magnetic tape can be interposed on the optical path until the light from the light-emitting element is received, and the running operation of the magnetic tape causes the end portion of the magnetic tape to When a portion of the outer peripheral surface of the light transmitting portion on which the magnetic tape is not wound appears,
A magnetic tape characterized in that the incident light from the light emitting element is received by the light receiving element via the first and second reflecting surfaces to detect that it is an end of the magnetic tape. It is an edge detection device.

[0009]

[Embodiment] An embodiment of the tape cassette and magnetic tape end detection device according to the present invention will be described in detail in the order of <First Embodiment> and <Second Embodiment> with reference to FIGS. 1 to 3. explain.

In the first and second embodiments of the tape cassette and magnetic tape end detection device according to the present invention, a pair of light emitting elements and light receiving elements provided in the magnetic recording/reproducing device are used to detect the magnetic field in the tape cassette. Without connecting the transparent leader tape described in the conventional example to the end (starting end or terminal end) of the tape, the end of the magnetic tape is fixed to the outer peripheral surface of a cylindrical hub and then wound, and then the hub A light transmitting part is formed using a member that transmits light from the light emitting element in at least a part of the circumferential direction near the outer peripheral surface of the hub to form a cylindrical shape, and a first and a second light transmitting part are formed in the light transmitting part. A reflective surface is formed with a light-transmitting member sandwiched therebetween, and the light from the light emitting element that is incident on the outer circumferential surface of the light transmitting section is redirected via the first and second reflective surfaces. A tape cassette is configured so that light is emitted from the surface and received by a light receiving element, and the tape cassette is mounted on a magnetic recording/reproducing device, and the magnetic tape is wound until it reaches the end of the magnetic tape by the running motion of the magnetic tape. When a portion of the outer circumferential surface of the light-transmitting portion that is not covered appears, the incident light from the light-emitting element is received by the light-receiving element via the first and second reflective surfaces, and it is detected that it is the edge of the magnetic tape. The common technical philosophy is to have this structure.

<First Embodiment> FIG. 1 shows a first embodiment according to the present invention.
FIG. 2 is a plan view showing the tape cassette and magnetic tape edge detection device of the first embodiment, taken in cross section along the line X-O-X shown in FIG. 1. FIG.

First, a tape cassette according to a first embodiment of the present invention will be explained with reference to FIGS. 1 and 2.

As shown in FIG. 2, the tape cassette 1A according to the first embodiment of the present invention is used in magnetic recording and reproducing devices such as video tape recorders (VTRs) and digital audio tape recorders (DATs). The lower half 2 and the upper half 3 are combined to form a rectangular box.

A pair of reels 4 (4A, 4B) are provided within the tape cassette 1A, with 4A being a supply reel and 4B being a take-up reel.

The structures of the supply reel 4A and take-up reel 4B described above will now be explained. Note that since the supply reel 4A and the take-up reel 4B have the same structure, the structure of the supply reel 4A will be explained, and the explanation of the structure of the take-up reel 4B will be omitted.

The supply reel 4A is integrally formed into an "E" shape as shown in the figure by a circular upper flange 5, a lower flange 6 of the same shape, and a cylindrical hub 7. That is, the upper flange 5 and the lower flange 6 face each other, and the hub 7 is provided vertically between the center part of the upper flange 5 and the center part of the lower flange 6, and these are integrated by press-fitting or the like. It is formed in an “E” shape. Above supply reel 4
Among the constituent members 5 to 7 of A, the hub 7 constitutes the main part of the first embodiment of the present invention.

Further, the hub 7, which is a main part of the first embodiment of the present invention, uses a member that transmits light from the light emitting element 13, which will be described later. A transparent light transmitting portion 7b is integrally formed in a cylindrical shape, and first and second reflective surfaces 7c and 7d are formed on the outer peripheral surface 7 within this light transmitting portion 7b.
The hub 7 is formed along the entire circumference, and furthermore, a hole 7e and an engaging part 7f are formed in the center of the interior, in which reel shaft mechanism parts 20A and 20B, which will be described later, are engaged, and this hub 7 is divided into several parts. Although it is integrally formed into a cylindrical shape, divisional illustration is omitted.

The first and second reflecting surfaces 7c and 7d are as follows:
As shown in the figure, the cross-sectional shape is formed into a trapezoidal prism shape with the outer circumferential surface 7a as the base and the inner side as the upper side (indicated by the two-dot chain line), and a first reflective surface 7c is formed on the upper slope in the figure. A second reflective surface 7d is formed on the lower inclined surface. Further, the first reflective surface 7c and the second reflective surface 7d are formed to be symmetrical with respect to the center line L with a member that transmits light from the light emitting element 13, which will be described later, interposed therebetween. Furthermore, the first and second reflective surfaces 7c and 7d are outer peripheral surfaces 7a.
The first reflective surface 7c and the second reflective surface 7d are inclined at an inclination angle of approximately 45 degrees with reference to the reel so that they approach each other toward the center of the reel, and the first reflective surface 7c and the second reflective surface 7d are spaced apart from each other by a very small distance across the center line L. are formed separately. In addition, without forming the first and second reflective surfaces 7c and 7d in the shape of a trapezoidal prism,
One end of the first reflective surface 7c and the second
It may be formed into a triangular prism-like cross-sectional shape that is internally connected to one end of the reflecting surface 7d. Further, the first and second reflective surfaces 7c and 7d are processed into mirror surfaces by depositing aluminum or the like using a well-known vapor deposition technique.

In particular, the light transmitting portion 7b is integrally formed as a component of the hub 7, and the light transmitting portion 7b has the first and second reflecting surfaces 7c and 7d inside the trapezoidal prism or triangular prism. Although it is at least necessary that only the hub 7 be made of a material that transmits light, no problem will occur even if the entire inside of the hub 7 is made of a material that transmits light. In the following description, the outer circumferential surface of the light transmitting portion 7b is shown to be the same surface as the outer circumferential surface 7a of the hub 7,
The description will be given using the same reference numerals.

At this time, as will be explained later in the detection operation, when the light from the light emitting element 13 is incident on the outer circumferential surface 7a of the light transmitting portion 7b of the hub 7, it is reflected by the first reflective surface 7c, and this reflected light is further reflected. The emitted light passes through the portion sandwiched between the transparent members, is also reflected on the second reflective surface 7d, and is emitted as return light from the outer circumferential surface 7a in the opposite direction to the incident direction. When the inclination angle of the first and second reflective surfaces 7c and 7d is 45 degrees with respect to the outer circumferential surface 7a, this is an ideal inclination angle in which the incident light and the returning light are separated from each other and become parallel lights. , even if the incident light and the returned light do not become parallel light due to some angular deviation, the light emitting element 13 that has entered the outer circumferential surface 7a
It is sufficient that the light from the outer circumferential surface 7a can be emitted as return light.

Further, as shown in FIG. 1, a lid 8 shown by a two-dot chain line is attached to the front side of the tape cassette 1A so that the lid can be opened and closed. Furthermore, tape guides 9 and 10 are installed at both left and right ends of the front side of the tape cassette 1A. The magnetic tape 11 wound on the supply reel 4A is wound onto the take-up reel 4B while adhering to tape guides 9 and 10. At this time, a transparent leader tape as shown in the conventional example is not connected to the starting end or the ending end of the magnetic tape 11, and the starting end of the magnetic tape 11 is wound around the outer periphery of the hub 7 of the reel 4B. The magnetic tape 11 is directly clamped and fixed to the surface 7a and then wound. On the other hand, the terminal end of the magnetic tape 11 is directly clamped and fixed to the outer peripheral surface 7a of the hub 7 of the supply reel 4A and then wound.

Further, a well-known reel brake mechanism member 12 is provided at the center of the rear side of the lower half 2 of the tape cassette 1A.
A reel brake mechanism member 12 is always in contact with the outer periphery of the lower flange 6 of the supply reel 4A and the outer periphery of the lower flange 6 of the take-up reel 4B to prevent the magnetic tape 11 from loosening. VTR, DA
When attached to a T or the like, a reel brake release member (not shown) protrudes from the lower hole 2a of the reel brake mechanism member 12 from below, and the reel brake mechanism member 12 is released.

Next, the reel shaft mechanisms 20A and 20B that rotationally drive the supply reel 4A and take-up reel 4B in the tape cassette 1A will be briefly described. When the tape cassette 1A is installed in a VTR, DAT, etc., the supply reel 4A and take-up reel 4B are engaged with the reel shaft mechanisms 20A and 20B, respectively, and are driven to rotate. Note that the reel shaft mechanism parts 20A and 20B have the same configuration on the supply reel 4A side and the take-up reel 4B side. The explanation about the side will be omitted.

Reel shaft mechanism section 20A on the supply reel 4A side
Now, the stepped reel shaft 2 fixed to the chassis 21
A gear 23 and a reel stand 24 are rotatably attached to the shaft 2. Further, a friction member 25 such as felt is interposed between the gear 23 that is pivoted on the lower side of the reel shaft 22 and the reel stand 24 that is pivoted on the upper side. Further, the large diameter portion 24a of the reel stand 24 protrudes from below the lower half 2 into the hole 2c and is in contact with the lower surface of the hub 7 of the supply reel 4A. Narrow diameter portion 24 of stand 24
A compression spring 26 is fitted into b, and a reel engaging member 27 is fitted from above the compression spring 26. Here, the narrow diameter part 24b of the reel stand 24 is formed in a hexagonal shape as shown in FIG. is constantly urged upward by the urging force of
Although upward movement is restricted by the E-washer 28, downward movement is allowed so that the tape cassette 1A can be easily engaged with the supply reel 4A when the tape cassette 1A is installed.

Further, as shown in FIG. 1, there is an engaging portion 27a protrudingly provided at a position where the outer periphery of the reel engaging member 27 is divided into three equal parts.
can be engaged at appropriate positions with a plurality of uneven engagement portions 7f formed in the hole 7e of the hub 7 of the supply reel 4A, and when the supply reel 4A rotates, the reel engagement member The driving force is transmitted between the engaging portion 27a of the supply reel 27 and the engaging portion 7f of the supply reel 4A. Furthermore, the biasing force of the compression spring 26 also acts downward, and the biasing force of the compression spring 26 acting on the reel stand 24 pushes the reel stand 24 toward the gear 23 via the friction member 25, so that the reel is always The stand 24 and the gear 23 are the friction member 25
The structure is integrated through the Also, gear 24
A gear of a drive transmission member connected to a drive source (not shown) meshes with the gear 23 and the reel stand 24 so that they can rotate as one, and the reel stand 24
The reel engaging member 27 fitted into the narrow diameter portion 24b can also rotate together, so that driving force can be transmitted to the supply reel 4A.

The reel shaft mechanism section 20A on the supply reel 4A side and the reel shaft mechanism section 20B on the take-up reel 4B described above.
As a result, the magnetic tape 11 wound between the supply reel 4A and the take-up reel 4B is run.

[0027] Here, an optical signal exchange means using a pair of light emitting element 13 and light receiving element 14, which is a main part of the present invention, will be explained.

As shown in FIG. 1, a hole 2b is bored near the front side of the lower half 2, and this hole 2b is located between the supply reel 4A and the take-up reel 4B, and between the upper and lower flanges. 5 and 6, and a pair of light emitting element 13 and light receiving element 14, which serve as optical signal transmitting and receiving means, are inserted into this hole 2b from below.

Returning to FIG. 2 again, the light emitting elements 13 (13A, 13B) and light receiving elements 14 (14A, 1
4B) is constituted by two sets of photosensors: a pair of light emitting element 13A and light receiving element 14A, and a pair of light emitting element 13B and light receiving element 14B. Although the types of components of the light emitting element 13 and the light receiving element 14 are not particularly limited, a lamp or a light emitting body (LED, EL, etc.) is used as a light source of the light emitting element 13. Furthermore, visible light or infrared light is used as the light from the light emitting element 13. In addition, a method is also adopted in which the light emitting element 13 is pulse-modulated, the light is received by the light receiving element 14, and the synchronization state and level of the received light and the light from the light emitting element 13 are compared to accurately distinguish it from extraneous light. Although it is possible, detailed explanation will be omitted here. Furthermore, if a thin magnetic tape 11 is used and there is a risk that the light from the light emitting element 13 will partially pass through the magnetic tape 11 and be erroneously detected by the light receiving element 14,
For example, controlling the intensity of the light from the light emitting element 13, appropriately selecting the wavelength of the light from the light emitting element 13, or including a large amount of a component that prevents light transmission in the magnetic layer of the magnetic tape 11. Through various methods, we aim to further improve detection accuracy.

Further, the light emitting element 13 (13A, 13B) and the light receiving element 14 (13B) inserted into the hole 2b of the lower half 2
4A, 14B) have two light emitting elements 13A, 13 above.
B, two light receiving elements 14A, 14B are attached to the support member 1 below.
It is fixedly supported by 5. Then, the pair of light emitting elements 13A and light receiving elements 14A form one set on the supply reel 4.
A pair of light emitting elements 13B and light receiving elements 14B form a pair and face the outer peripheral surface 7a of the hub 7 of the take-up reel 4B. There is also a method in which one light emitting element 13A, 13B is used as a common light source for the supply reel 4A side and the take-up reel 4B side, without having to separate them. In addition, the light emitting element 13 (13A, 1
3B) and the light-receiving elements 14 (14A, 14B) without any problem even if the vertical positions are switched.

Here, the magnetic tape end detection of the first embodiment using the light emitting elements 13 (13A, 13B) and the light receiving elements 14 (14A, 14B) of the optical signal transmitting/receiving means which are the essential parts of the present invention with the above configuration will be described. The detection operation of the device will be explained using FIGS. 1 and 2 together.

First, the detection operation of the magnetic tape end detection device of the first embodiment in the configuration shown in FIGS. 1 and 2 can be applied not only to the supply reel 4A side but also to the take-up reel 4B side having the same configuration. It is. Furthermore, the magnetic tape end detection operation is defined as being able to detect either the start end and/or the end end of the magnetic tape 11 as an end of the magnetic tape 11.

To explain this detection operation step by step, the transparent leader tape explained in the conventional example is not connected to the starting end and the ending end of the magnetic tape 11, and the supply reel 4A is
Before the magnetic tape 11 is sent from the side to the take-up reel 4B side, the outer peripheral surface 7a of the hub 7 of the take-up reel 4B
Although the starting end of the magnetic tape 11 is directly clamped and fixed to the light transmitting portion 7, the magnetic tape 11 is not wound.
The outer circumferential surface portion b is also exposed. Here, the light from the light emitting element 13B on the take-up reel 4B side travels straight parallel to the upper and lower flanges 5 and 6 toward the outer peripheral surface 7a of the hub 7 of the take-up reel 4B, especially when the magnetic tape 11 is wound. When the light enters the light transmitting portion 7b in the normal direction from the outer peripheral surface portion of the light transmitting portion 7b that is not The optical path is diverted downward, and this light is further reflected at a substantially right angle by the lower second reflecting surface 7d, returns to the outside from the outer circumferential surface 7a, and is emitted as light. The light emitted outward from the outer peripheral surface 7a of the hub 7 is parallel to the incident light, but passes through an optical path spaced apart below the incident light, and is received by the light receiving element 14B installed below the light emitting element 13B. Ru. Through these operations, the start end, that is, the end, of the magnetic tape 11 is detected on the take-up reel 4B side.

On the other hand, on the supply reel 4A side, the magnetic tape 1
After the terminal end of the magnetic tape 11 is held between the outer peripheral surface 7a of the hub 7 of the supply reel 4A, the magnetic tape 11 is wound many times. 11, and the light transmitting portion 7 of the hub 7
Therefore, the returned light from the light emitting element 13A does not reach the light receiving element 14A, so that the light receiving element 14A cannot receive the light. Due to these operations, the supply reel 4A does not detect the end (terminating end) of the magnetic tape 11.

After that, the reel shaft mechanism section 20A of the supply reel 4A side and the reel shaft mechanism section 20B of the take-up reel 4B
When the magnetic tape 11 is run and all of the magnetic tape 11 wound around the supply reel 4A is wound onto the take-up reel 4B, the process is completely reversed, so that the outer peripheral surface of the hub 7 of the supply reel 4A On 7a, a portion where the end portion of the magnetic tape 11 is sandwiched and an outer peripheral surface portion of the light transmitting portion 7b where the magnetic tape 11 is not wound appear. Here, when the light from the light emitting element 13A is incident on the outer peripheral surface portion of the light transmitting section 7b where the magnetic tape 11 is not wound, the first and second reflecting surfaces 7c and 7d in the light transmitting section 7b are The light is emitted from the outer circumferential surface 7a, is received by the light receiving element 14A, and is detected as the end of the magnetic tape 11, that is, the end.
On the other hand, on the take-up reel 4B side, it is blocked by the magnetic tape 11 and is not detected as an end (starting end).

Furthermore, as shown in FIG. 1, the supply reel 4A
side and take-up reel 4B side (13A, 1
3B), the light receiving element 14 (14A, 14B) is attached to the lower half 2
The light-emitting element 13A and the light-receiving element 14A on the supply reel 4A side are installed at the position marked ■ in the figure on the front side in the lower half 2, without being installed in the hole 2b of the take-up reel 4B side. It is also possible to install the light-receiving element 14B in the lower half 2 at the position indicated by ▪ in the figure on the front side. In addition, it is assumed that the lower half 2 is opened at the positions marked ``■'' and ``■'' in the figure. Furthermore, when the lower half 2 and upper half 3 of the tape cassette 1A are formed of a material that transmits the light from the light emitting element 13, a pair of light emitting elements are placed at appropriate positions along the outer side surface of the tape cassette 1A. 13 and light receiving element 1
It is also possible to install one set each of 4 on the supply reel 4A side and on the take-up reel 4B side.

As described in detail above, in the tape cassette and magnetic tape end detection device of the first embodiment, the magnetic tape 11
There is no need to connect a conventional transparent leader tape to the end of the magnetic tape 11, and the tape cassette 1A loaded with the magnetic tape 11 can be provided to consumers at a low cost. In addition, since the adhesive for connecting the transparent leader tape is not required and the adhesive does not change over time, the magnetic tape 11
There is an advantage that the reliability and quality of the tape cassette 1A equipped with the tape cassette 1A are significantly improved.

Furthermore, in the magnetic recording and reproducing apparatus, the pair of light emitting elements 13 and light receiving elements 14 can be freely installed inside and outside the tape cassette 1A with space efficiency, so the degree of freedom when designing the magnetic recording and reproducing apparatus is increased. It becomes possible to realize miniaturization of the device.

Although detailed description is omitted here, even if the transparent leader tape described in the conventional example is connected to the end of the magnetic tape 11, the above can be achieved by using the hub 7, which is the essential part of the present invention. Similarly, the end of the magnetic tape 11 can be detected without any problem.

<Second Embodiment> FIG. 3 shows a second embodiment according to the present invention.
FIG. 2 is a plan view showing a tape cassette and a magnetic tape end detection device according to an embodiment.

In the tape cassette and magnetic tape end detection device of the second embodiment, the hub 7 in the first embodiment is
The first and second reflective surfaces 7c formed in the light transmitting portion 7b of
, 7d are formed along the entire circumference of the outer circumferential surface 7a, but are equivalent to being formed only on a part of the circumferential direction of the outer circumferential surface 7a. , and other configurations are the same as the first embodiment, so only the points different from the first embodiment will be explained here.

In FIG. 3, the tape cassette 1B of the second embodiment differs only in the structure of the hub 16 from the hub 7 of the first embodiment.

That is, in the second embodiment, the magnetic tape 11
A clamper 17 is used to secure the end (starting end or terminal end) of the hub 16 to the hub 16. This clamper 17 is the hub 1
The magnetic tape 11 is fitted into the recess 16b of No. 6, and the end (starting end or terminal end) of the magnetic tape 11 is held between the clamper 17 and the recess 16b. Then, the clamper 17
b, the outer peripheral surface 17a of the clamper 17 and the hub 1
The outer circumferential surface 16a of No. 6 is the same cylindrical surface, and the shape is equivalent to that of an integrally formed cylinder. Thereby, the clamper 17 has a function as a part of the hub 16. That is, the length R of the arc of the clamper 17 is formed to be the length of a part of the outer peripheral surface 16a of the hub 16.

The clamper (light transmitting section) 17 is made of a transparent member capable of transmitting light from the light emitting element 13, and is formed in the same manner as the light transmitting section 7b of the first embodiment. Therefore, first and second reflective surfaces corresponding to the first and second reflective surfaces 7c and 7d (FIG. 2) of the first embodiment are formed inside the clamper 17, but in FIG. The illustration of the first and second reflective surfaces is omitted. Needless to say, the ends (starting end or ending end) of the magnetic tape 11 are fixed by the clamper 17 and then wound around the outer circumferential surface 16a of the hub 16 and the outer circumferential surface 17a of the clamper 17. On the other hand, the first and second reflective surfaces equivalent to the first and second reflective surfaces 7c and 7d (FIG. 2) of the first embodiment are not formed in the hub 16, and are simple and almost the same as the conventional example. It has a structure. Therefore, in the second embodiment, the first and second reflecting surfaces, which are the essential parts of the invention, are formed inside the clamper 17, which is a part of the hub 16. Since the only part is inside the clamper 17, manufacturing costs can be reduced.

Furthermore, in the second embodiment, the optical signal transmitting and receiving means using a pair of light emitting elements 13 and light receiving elements 14, which are the essential parts of the invention, can be installed in the same position as in the first embodiment. Yes, the explanation is omitted here.

Note that in the tape cassette and magnetic tape end detection device of the first and second embodiments described above,
A tape cassette incorporating a hub with a flange-less configuration in which a magnetic tape 11 is simply wound around the hub 7 of the first embodiment or the hub 16 and clamper 17 of the second embodiment without providing upper and lower flanges 5 and 6. But it's okay. At this time, the light from the light emitting element 13 is transmitted to the outer peripheral surface 7a of the light transmitting portion 7b (17).
(17a), and the incident light passes through the first and second reflective surfaces 7c and 7d to the outer peripheral surface 7 of the light transmitting portion 7b (17).
a (17a) and can be received by the light receiving element 14,
In addition, the pair of light emitting elements 13 and light receiving elements 14 may be installed at positions where the magnetic tape 11 can be interposed on the optical path until the light from the light emitting elements 13 is received, and where they will not interfere with the winding of the magnetic tape 11. .

Furthermore, in the first and second embodiments, a configuration in which a pair of reels 4 (4A, 4B) are provided in the tape cassettes 1A, 1B has been described, but the present invention is not limited to this, and a single reel or A tape cassette containing a single hub may also be used. In this configuration, the starting end of the magnetic tape 11 is fed into the winding side of the device by a loading means (not shown) and wound up, and the magnetic tape 11 is inside the tape cassette.
The end portion, that is, the terminal end portion is fixed to the hub 7 of the first embodiment or the clamper 17 of the second embodiment, and then wound around the hub 7 or the hub 16. In this case, the end of the magnetic tape 11, that is, the terminal end, is connected to a pair of light emitting elements 13.
Detection can be performed by an optical signal exchange means using the light receiving element 14.

[0048]

According to the tape cassette and magnetic tape end detection device according to the present invention described in detail above, in the tape cassette according to claim 1, the end of the magnetic tape in the tape cassette has Without connecting a transparent leader tape, the end of the magnetic tape is fixed to a cylindrical hub and then wound, and the light from the light emitting element is transmitted through at least a part of the circumferential direction near the outer peripheral surface of the hub. A light transmitting portion is formed using a member that forms the hub into a cylindrical shape, and
First and second reflective surfaces are formed in the light transmitting part with a light transmitting member sandwiched therebetween, and a magnetic tape is generated by an optical signal transmitting/receiving means using a pair of light emitting elements and light receiving elements provided in the magnetic recording/reproducing apparatus. The structure is configured so that the end of the frame can be detected. This eliminates the conventional work of connecting a transparent leader tape to the end of the magnetic tape in the tape cassette, making it possible to provide consumers with tape cassettes loaded with magnetic tape at low cost. Further, since an adhesive for connecting the transparent leader tape is not required and the adhesive does not change over time, there is an advantage that the reliability and quality of the tape cassette equipped with the magnetic tape are significantly improved.

Furthermore, in the magnetic tape end detection device according to claim 2, the tape cassette according to claim 1 is used, and the outer circumferential surface of the light transmitting portion where the magnetic tape is not wound is reached by the running operation. When the portion appears, the light from the light emitting element that enters this outer peripheral surface portion is emitted from the outer peripheral surface via the first and second reflective surfaces, and is received by the light receiving element, indicating that it is an end of the magnetic tape. is being detected. On this occasion,
In a magnetic recording and reproducing device, a pair of light emitting elements and a light receiving element can be freely installed inside and outside a tape cassette in a space efficient manner, increasing the degree of freedom when designing the magnetic recording and reproducing device and realizing miniaturization of the device. becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a tape cassette and a magnetic tape end detection device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal cross-sectional view of the tape cassette and magnetic tape end detection device of the first embodiment of the present invention taken along the line X-O-X shown in FIG. 1;

FIG. 3 is a plan view showing a tape cassette and a magnetic tape end detection device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the configuration of a conventional magnetic tape edge detection device.

[Explanation of symbols]

1A...tape cassette, 1B...tape cassette, 4...reel, 4A...supply reel, 4B...take-up reel, 7...hub, 7a...outer peripheral surface portion, 7b...light transmitting portion, 7c...first reflective surface, 7d... Second reflective surface, 11... Magnetic tape, 13 (
13A, 13B)...Light emitting element, 14 (14A, 14B)
...Light receiving element, 16...Hub, 17...Light transmitting part (clamper)
.

Claims (2)

[Claims] 1. The magnetic tape is wound around a cylindrical hub with an end portion of the magnetic tape fixed to the hub, and when installed in a magnetic recording/reproducing device, a pair of light emitting elements provided in the magnetic recording/reproducing device. and a tape cassette in which the end of the magnetic tape is detected by an optical signal exchange means using a light receiving element, a member that transmits light from the light emitting element to at least a part of the circumferential direction near the outer peripheral surface of the hub. The hub is formed into a cylindrical shape by forming a light transmitting portion using a cylindrical material, and first and second reflective surfaces are formed with a light transmitting member sandwiched between the hub and the light transmitting portion. The light from the light emitting element that has entered the outer circumferential surface of the light emitting element is redirected through the first and second reflective surfaces, and is emitted from the outer circumferential surface of the light transmitting part, and is received by the light receiving element. A tape cassette featuring 2. A magnetic tape end detection device that uses the tape cassette according to claim 1 to detect the end of the magnetic tape wound around the hub by means of optical signal transmission and reception using a pair of light emitting elements and light receiving elements. The light from the light emitting element is made incident on the outer circumferential surface of the light transmitting section, and the incident light is emitted from the outer circumferential surface of the light transmitting section via the first and second reflecting surfaces to receive the light. The light-emitting element and the light-receiving element are provided so that the magnetic tape can be interposed on the optical path from when the light is received by the element to when the light from the light-emitting element is received. When the outer circumferential surface of the light transmitting part on which the magnetic tape is not wound appears at the end of the tape, the incident light from the light emitting element is received through the first and second reflective surfaces. 1. A magnetic tape end detection device, characterized in that it is configured to detect an end of the magnetic tape by receiving light with an element.