JPH04366484A - Tape end detector and tape cassette - Google Patents

Abstract

PURPOSE:To prevent deterioration in recording and reproducing characteristic by checking light of a light emitting element with a photodetector to detect the end of a tape when a reel arranged between reels on the supply and receiving sides is wound completely on one hand so that dust and dirts are made hard to enter. CONSTITUTION:Furning forces of reel shafts 11a and 11b are transmitted to turn a reel 2a on the supply side and a reel 2b on the winding side and a magnetic tape 3 is wound onto the reel 2b from the reel 2a. At this point. light R radiated to respective photodetectors 12a ad 12b on the sides of the reels 2a and 2b is shielded with a tape wound covering a winding surface of the tape and hence, none of the light emitted from light emitting elements 10a and 10b is detected. But as the tape 3 is wound with the reel 2b to reach the end of the tape, the light R from the element 10a is detected with the photodetector 12a thereby allowing the detection of light reaching the tape end. Conversely when the tape 3 is wound with the reel 2a. the same is done.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape end detection device and a tape cassette.

0002

BACKGROUND OF THE INVENTION It is well known that tape cassettes have been used in recording and/or reproducing devices (hereinafter simply referred to as recording and reproducing devices) such as video tape recorders. To give an overview of such tape cassettes, generally speaking, a supply reel and a take-up reel are disposed inside a case body formed by combining an upper half and a lower half made of plastic. A magnetic tape is stretched over a predetermined path between the side reel and the take-up reel, and a front cover that can be opened and closed by rotation is provided to protect the magnetic tape located outside the case body. ing.

When such a tape cassette is loaded into a recording and reproducing device, the front lid opening mechanism of the recording and reproducing device is activated to open the front lid, and the tape loading member of the recording and reproducing device enters through the bottom opening of the tape cassette. However, when the tape loading member moves toward the front opening of the tape cassette, the tape is pulled out, the tape is attached to the magnetic head, and a recording/reproducing operation is performed.

As the recording and reproducing operation progresses, the magnetic tape is wound from the supply reel to the take-up reel, and when the magnetic tape wound on the supply reel runs out, that is, the magnetic tape is wound on the take-up reel. When the magnetic tape is completely wound, it is detected that the end of the tape has been reached, and the reel disk connected to the supply reel and take-up reel is configured to stop.

[0005] This tape end detection mechanism includes, for example, a light emitting element and a light receiving element provided on the recording/reproducing apparatus side, and an opening window formed in the side wall of the tape cassette. That is, when a tape cassette is loaded into a recording/reproducing device, the light emitting element and the light receiving element are positioned so as to sandwich the magnetic tape in the tape cassette, and when the tape does not reach the end of the tape, the light from the light emitting element is transmitted through the opaque magnetic field. Since the light is blocked by the tape and does not reach the light-receiving element, it is detected that the light has not reached the end of the tape, and when it reaches the end of the tape, the light from the light-emitting element is connected to the magnetic tape by the transparent tape (leader tape) at the end of the tape. ) and the opening window of the tape cassette to reach the light receiving element, from which it is detected that the tape end has been reached.

However, such a tape end detection mechanism requires that an opening window for light passage be formed in the tape cassette, and therefore dust and dust may enter the tape cassette through this opening window. It adheres to the magnetic tape, making dropouts more likely to occur, and recording and reproducing characteristics may deteriorate. In particular, the higher the density of the magnetic tape, the more countermeasures against dirt and dust are required, and the tape end detection mechanism configured as described above is not preferable.

[0007] Furthermore, a leader tape is always required at both ends of the magnetic tape, and for this reason, it is necessary to join the magnetic tape and the leader tape with a splicing tape, and this work increases costs. Furthermore, since there are steps in the splicing tape, when the magnetic tape is wound around the supply reel and take-up reel, steps are formed, which can cause magnetic powder to fall, making dropouts more likely to occur. .

[0008]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a tape end detection technique that prevents dust and dust from entering and deteriorating recording and reproducing characteristics. The object of the present invention is to provide a supply reel and a take-up reel, a tape disposed on a path between the supply reel and the take-up reel, and a tape provided on the supply reel and take-up reel. a reel bearing section, a reel drive shaft that can enter the reel bearing section, a light emitting element or a light receiving element provided on the reel drive shaft, and a light receiving element or the light receiving element provided opposite to the light emitting element or light receiving element. and a light emitting element, and when the tape is completely wound on one of the supply reel or the take-up reel, the light from the light emitting element is detected by a light receiving element, and the end of the tape can be detected. This is achieved by a tape end detection device characterized by the following.

[0009] Also, a supply reel and a take-up reel, a tape disposed in a path between the supply reel and the take-up reel, and a case for storing the supply reel and take-up reel. When this tape cassette is installed in a recording and/or reproducing device, the supply reel and the take-up reel have a reel drive shaft on the recording and/or reproducing device side. A reel bearing part into which a light emitting element or a light receiving element arranged in the reel can enter, the light emitting element or light receiving element located inside the reel bearing part and a recording and/or reproducing device provided opposite thereto. This is achieved by a tape cassette characterized in that it is configured so that light can be detected between the light receiving element or the light emitting element on the side, and the end of the tape can be detected.

That is, when the tape cassette constructed as described above is installed in a recording and/or reproducing apparatus (hereinafter referred to as a recording/reproducing apparatus), the light receiving element on the recording/reproducing apparatus side is set at a predetermined position on the tape cassette, and A reel drive shaft having a light emitting element attached to its tip, for example, is engaged with a reel bearing portion of a supply reel. Then, a recording/reproducing operation is performed, the supply reel and the take-up reel rotate, and the magnetic tape wound on the supply reel is wound onto the take-up reel. Incidentally, although light is emitted from the light-emitting element at the tip of the reel shaft engaged with the supply reel toward the light-receiving element, while the tape is running on the way to the tape end,
That is, when the magnetic tape is wound around the supply reel, light from the light emitting element is absorbed by the magnetic tape and does not reach the light receiving element. When the recording/reproducing operation continues and the magnetic tape is wound on the take-up reel and no magnetic tape is wound on the supply reel, the light from the light emitting element is transmitted to the supply reel made of transparent material. The signal reaches the light receiving element through the hub portion (tape winding surface portion) of the side reel or the hole formed in the hub, and by detecting this signal, it is determined that the tape end has been reached.

[0011] Therefore, there is no need for an opening window for light transmission in the side wall of the tape cassette, which was required in the conventional tape end detection mechanism, making it difficult for dirt and dust to enter the tape cassette, thereby reducing dropouts and the like. This is less likely to occur and can prevent deterioration of recording and reproducing characteristics. In particular, the higher the density of magnetic tape, the more dust and dust countermeasures are required for magnetic tape such as vapor-deposited tape and metal tape, and tape cassettes for such magnetic tapes. It becomes even more preferable.

Furthermore, it is not necessary to provide leader tapes at both ends of the magnetic tape, that is, the tape end detection mechanism does not require leader tapes, and therefore there is no need to join the magnetic tape and leader tape with splicing tape. This is advantageous in terms of cost. Furthermore, unlike when using splicing tape, no steps are formed, and even when the magnetic tape is wound around the supply reel or take-up reel, no steps are formed on the tape surface, and the magnetic tape does not suffer from folds or the like. Because it is less susceptible to damage, particles such as magnetic powder are less likely to fall off, and dropouts are less likely to occur.

[0013]

[Embodiment] Figures 1 to 6 show an embodiment of the tape cassette according to the present invention. Figure 1 is a schematic perspective view of the entire tape cassette, and Figure 2 shows the tape cassette installed in a recording/reproducing device. 3 is a schematic cross-sectional view of the reel drive shaft entering the reel, FIG. 4 is a cross-sectional view of the light-receiving element entrance part, FIG. 5 is a perspective view thereof, and FIG. 6 is a cross-sectional view of the light-receiving element entrance stage. It is.

The case body 1 constituting the tape cassette A is composed of a rectangular upper half 1a and a lower half 1b made of synthetic resin such as polypropylene, polystyrene, ABS resin, etc. The half 1b and the half 1b are fitted into each other from above and below, and are screwed together with set screws to form an integral housing shape. Furthermore, upper half 1
The mating surfaces of a and the lower half 1b are configured in a concave-convex or "" shape, and when the two are mated together, the structure makes it difficult for dust and dirt to enter the inside of the case body 1 from the mating surfaces. .

A pair of tape reels, namely a supply reel 2a and a take-up reel 2b, are rotatably housed in the case body 1, and the magnetic tape 3 is connected to the supply reel 2a and take-up reel 2b. It is wrapped and stretched between. Both tape reels are placed on the bottom plate of the lower half 1b, and their lower ends are positioned by fitting into reel fitting holes provided in the bottom plate.

[0016] Also, the supply side reel 2a and the take-up side reel 2b
In order to bias the supply reel 2a and take-up reel 2b toward the lower half 1b, a stainless steel presser spring 4 is provided at a predetermined position on the inner surface of the upper half 1a.
is welded. On the front surface of the case body 1, a front opening 5 is provided at approximately the center of the front wall 1c of the tape cassette (the front wall of the upper half 1a and the front wall of the lower half 1b). is provided with a bottom opening 6 that is continuous with the front opening 5. Then, the tape loading member of the recording/reproducing apparatus enters the pocket formed by the front opening 5 and the bottom opening 6 from the bottom opening 6, pulls out the magnetic tape 3 from the tape cassette A, and performs recording/reproduction on the recording/reproducing apparatus. It is configured so that recording and reproduction is performed by passing it around a mechanism B (rotating drum B1, various heads B2, various tape guides B3). The width of the front opening 5 should be such that the tape loading member of the recording/reproducing device can enter and pull out the tape 3 from the tape cassette A. It doesn't have to be as big as a tape cassette.

Reference numeral 7 denotes a lid that can open and close the pocket formed by the front opening 5 and the bottom opening 6. This lid 7 is of a sliding type, and as shown in FIG. 1, the lid 7 is slid to the right. When the lid 7 is open, the magnetic tape 3 can be pulled out to the front of the case main body 1. The lid 7 can be closed by sliding it to the left. When the magnetic tape 3 is stored in the case body 1 with the lid 7 closed, the magnetic tape 3 is completely shielded from the outside. The degree of sealing is extremely high. Any mechanism may be used for attaching the lid 7 to the case body 1. For example, there is a means for forming a slide groove on the case body 1 side and a convex portion on the lid 7 side that engages with the slide groove. . In addition, the lid 7 and the case body 1 to which the lid 7 corresponds are provided with a click/clock mechanism with projections and recesses depending on the opening/closing position, so that the lid 7 can be held open/closed in each position. ing. Note that the lid 7 is a molded product made of synthetic resin such as polypropylene, polystyrene, polyacetal, ABS resin, or the like. Further, although the lid 7 is arranged inside the front wall 1c of the tape cassette, it may be arranged outside the front wall 1c of the tape cassette.

Tape guides 8a and 8b are provided on both sides of the front opening 5 to prevent the magnetic tape 3 from coming into contact with the front wall 1c and being damaged when the magnetic tape 3 is pulled out. Also, tape guides 9a, 9b are provided on both sides of the bottom opening 6 at a position rearward of the tape guides 8a, 8b and forward of the innermost end 6a of the bottom opening 6.
is provided. Note that the magnetic tape 3 is attached to the tape guides 9a and 9b when the magnetic tape 3 is not pulled out of the case body 1.

Reference numerals 10a and 10b are light emitting elements, and these light emitting elements 10a and 10b are attached to the ends of reel shafts 11a and 11b that rotationally drive the supply reel 2a and take-up reel 2b, and the tape cassette A is When loaded into the recording/reproducing apparatus, the reel shafts 11a and 11b enter into the reel bearings of the supply reel 2a and the take-up reel 2b, and as shown in FIG. 10b is also located within the reel bearing section.

Here, the hub 2a-1 of the supply reel 2a
At least a portion of the hub 2b-1 of the take-up reel 2b is made of a transparent material. Therefore, as shown in FIG. 3, the light emitting element 10a located inside the reel bearing
If the magnetic tape 3 is not wound around the hubs 2a-1 and 2b-1, the light from the hub 10b is irradiated to the outside thereof.

Reference numerals 12a and 12b are light receiving elements, and the light receiving elements 12a and 12b are irradiated with light from the light emitting elements 10a and 10b, and the tape winding surfaces (hubs 2a-1, 2b) of the supply reel 2a and the take-up reel 2b -1) to detect the light R passing through. Note that these light receiving elements 12a
, 12b also enter the cylindrical part through the hole 13 provided at the bottom of the tape cassette when the tape cassette A is installed in the recording/reproducing apparatus, and pass through the window made of a transparent material in this cylindrical part to the supply side. It is configured to be able to detect the light R passing through the tape winding surfaces of the reel 2a and the take-up reel 2b.

At the entrance of the hole 13, as shown in FIGS. 4 to 6, a dustproof member composed of a split elastic member 1d is arranged, and when the tape cassette A is installed in the recording/reproducing apparatus, The light receiving elements 12a and 12b on the recording/reproducing device side are in the hole 1.
The tape cassette A is configured such that it can enter the tape cassette A from the tape cassette A. When the tape cassette A constructed as described above is loaded into a recording/reproducing apparatus, the light receiving elements 12a, 12b of the recording/reproducing apparatus are set at predetermined positions within the tape cassette A, as shown in FIGS. 1 and 3. Further, reel shafts 11a and 11b of the recording/reproducing device are coupled to a supply reel 2a and a take-up reel 2b. Then, the rotational force of the reel shafts 11a and 11b is transmitted by the recording/reproducing operation, causing the supply reel 2a and the take-up reel 2b to rotate, and the magnetic tape 3 is wound from the supply reel 2a toward the take-up reel 2b. It will be taken away. At this time, light R is emitted from the light emitting elements 10a and 10b of the supply reel 2a and the take-up reel 2b toward the light receiving elements 12a and 12b, respectively. Here, when the magnetic tape 3 is wound around the supply reel 2a, the light R emitted toward the light receiving elements 12a and 12b is absorbed by the magnetic tape wound so as to cover the tape winding surface. 3, the light R emitted from the light emitting elements 10a and 10b is shielded by the light receiving elements 12a and 12a.
12b cannot be detected. However, when the magnetic tape 3 is not wound on the supply reel 2a, that is, when it is completely wound on the take-up reel 2b and reaches the tape end, the tape winding surface of the supply reel 2a (hub 2a- 1) is released from the covering by the magnetic tape 3, so the light R emitted from the light emitting element 10a reaches the light receiving element 12.
a can now be detected. Therefore, the light receiving element 12a detects the light R, and it is possible to detect that the light R has reached the end of the tape. Conversely, the same applies when the magnetic tape 3 is rewound from the take-up reel 2b to the supply reel 2a.

[0023] Such a tape end detection mechanism eliminates the need to form an opening in the side wall of the tape cassette as in the conventional case, making it difficult for dirt and dust to enter the tape cassette, preventing dropouts, etc., and improving recording performance. It is possible to prevent deterioration of playback characteristics. In particular, high-density magnetic tapes such as vapor-deposited tapes and metal tapes require more dust and dirt countermeasures.
It is more preferable as a tape cassette for such a high-density magnetic tape.

Further, it is not necessary to provide leader tapes at both ends of the magnetic tape 3 as in the prior art, that is, the tape end detection mechanism does not require a leader tape, and therefore the magnetic tape and leader tape can be connected to a splicing tape. This eliminates the need for jointing, which is advantageous in terms of cost. Furthermore, unlike when splicing tape is used, no steps are formed, and even when the magnetic tape is wound around the supply reel or take-up reel, no steps are formed on the magnetic tape surface.
Particles such as magnetic powder are less likely to fall off, and dropouts are less likely to occur.

In the above embodiment, the light emitting element is provided on the reel shaft, but the light receiving element may be provided on the reel shaft.

[0026]

[Effects] ■ The opening window for light transmission on the side wall of the tape cassette, which was required in the conventional tape end detection mechanism, is no longer required, making it difficult for dust to enter the tape cassette and causing dropouts. It is possible to prevent deterioration of recording and reproducing characteristics. In particular, the higher the density of magnetic tape, the more dust and dust countermeasures are required for magnetic tape such as vapor-deposited tape and metal tape, and tape cassettes for such magnetic tapes. preferred as ■ Leader tapes do not need to be provided at both ends of the magnetic tape, that is, leader tapes are not required for the tape end detection mechanism, and therefore there is no need to join the magnetic tape and leader tape with splicing tape, and splicing Unlike when using tape, no steps are formed on the tape surface even when the magnetic tape is wound around the supply reel or take-up reel, making it difficult for damage such as bending to the magnetic tape. It is difficult for powders such as magnetic powder to fall off, and dropouts are less likely to occur.

[Brief explanation of drawings]

FIG. 1 is an overall schematic perspective view of a tape cassette according to the present invention.

FIG. 2 is a schematic diagram showing a state in which a tape cassette is installed in a recording/reproducing device.

FIG. 3 is a schematic cross-sectional view at a stage when the reel drive shaft has entered the reel.

FIG. 4 is a sectional view of a light receiving element entrance part.

FIG. 5 is a perspective view of a light receiving element entrance part.

FIG. 6 is a cross-sectional view of a stage of entering a light receiving element.

[Explanation of symbols]

A Tape cassette 2a Supply side reel 2b Take-up side reel 2
a-1, 2b-1 Hub 3 Magnetic tape 1
0a, 10b Light emitting element 11a, 11b Reel shaft 12a, 12b Light receiving element

Claims (2)

[Claims] Claim 1: A supply reel and a take-up reel, a tape disposed on a path between the supply reel and the take-up reel, and a tape provided on the supply reel and the take-up reel. A reel bearing part, a reel drive shaft that can enter the reel bearing part, a light emitting element or a light receiving element provided on the reel driving shaft, and a light receiving element or light emitting element provided opposite to the light emitting element or light receiving element. and configured such that when the tape is completely wound onto one of the supply reel or the take-up reel, the light from the light emitting element is detected by the light receiving element so that the end of the tape can be detected. A tape edge detection device featuring: 2. A case for storing a supply reel and a take-up reel, a tape disposed on a path between the supply reel and the take-up reel, and the supply reel and take-up reel. When this tape cassette is installed in a recording and/or reproducing device, the supply reel and the take-up reel have a reel drive shaft on the recording and/or reproducing device side. A reel bearing part into which a light emitting element or a light receiving element arranged in the reel can enter, the light emitting element or light receiving element located inside the reel bearing part and a recording and/or reproducing device provided opposite thereto. 1. A tape cassette characterized in that the tape cassette is configured so that light can be detected between the light receiving element or the light emitting element on the side, and the end of the tape can be detected.