JPH05325321A - Tape end detector - Google Patents

Abstract

PURPOSE:To prevent an error in tape end detection due to a small hole existing on a tape or the irregular reflection or refraction of light in a cassette half and to increase the time allowance before the tape is stopped after the tape end detection. CONSTITUTION:The outer peripheral surfaces of a supply side reel hub 4 and take-up side reel hub 5 in the cassette half 3 consist of a material having the reflectivity higher than the reflectivity of the magnetic tape 1. Light emitting parts 10, 12 and light receiving parts 11, 13 are respectively provided to face the supply reel side and the take-up reel side on a lighthouse 2. The light transmitted through the tape reflects on the outer peripheral surfaces of the supply side reel hub 4 and the take-up side reel hub 5 in the transparent leader tape part and trailer tape part which are the tape ends of the magnetic tape 1. This light is detected in the light receiving parts 11, 13 and the magnetic tape 1 stops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape end detecting device for a recording / reproducing device using a magnetic tape.

[0002]

2. Description of the Related Art Here, an example of a conventional VTR will be described. As shown in FIG. 2A, the conventional VTR has a lighthouse 27 having a structure that is inserted into the cassette when the cassette is loaded. This lighthouse 27 is shown in FIG.
As described above, the magnetic tape 1 is provided with the supply side light emitting section 24 and the winding side light emitting section 25 for detecting the beginning portion and the end portion. Also, the first part of the magnetic tape (hereinafter referred to as the leader tape) and the last part (hereinafter referred to as the leader tape)
The trailer tape is a transparent tape not coated with a magnetic material, and the light from the lighthouse 27, which is transmitted through the trailer tape, that is, the trailer tape detecting light 23 and the leader tape detecting light 26, is transferred to the cassette. Supply side light receiving parts 2 provided on the take-up reel side and the supply reel side outside the half, respectively.
1 and the take-up side light receiving section 22 detect the tape end.

[0003]

In this conventional tape end detecting device, when light passes through a small hole not coated with a magnetic material, which is generated when a magnetic tape is manufactured, the tape end is erroneously detected. There was a fear that Also, since the distance from the light emitting unit to the light receiving unit is large, the diffused reflection and refraction of the light generated in the cassette half causes the light from the light emitting unit to leak to the light receiving unit, and the tape end is erroneously detected. There was a fear that

[0004]

SUMMARY OF THE INVENTION A tape end detection device of the present invention comprises a reel hub made of a material having a reflectance higher than that of a magnetic tape surface, and a light emitting portion and a light receiving portion directed toward the rotation center of the reel hub. And a lighthouse that receives the reflected light from the reel hub and detects the tape end.

[0005]

The present invention will be described below with reference to the drawings.

1A and 1B show an embodiment of the present invention, FIG. 1A is a plan view showing the entire structure, and FIG. 1B is a perspective view showing the lighthouse in detail in this embodiment.

In the present embodiment, the outer peripheral surfaces of the supply-side reel hub 4 and the winding-side reel hub 5 provided on the cassette half 3 are made of mirror-finished metal,
It has a sufficiently higher reflectance than the surface of the magnetic tape 1. Further, the lighthouse 2 having a structure to be inserted into the cassette when the cassette is loaded is inserted near the supply reel hub 4 and the take-up reel hub 5 and at a position substantially equidistant from the reel hub 4 and the reel hub 4. The take-up reel hub 5 includes a supply-side light emitting unit 10, a winding-side light emitting unit 12, a supply-side light receiving unit 11, and a winding-side light receiving unit 13, which are oriented toward the respective rotation centers.

Next, the operation of this embodiment will be described. When the tape feeding of the magnetic tape 1 from the supply reel hub 4 through the tape guide 14 is completed and the transparent trailer tape portion is reached, the trailer tape detection light 6 from the light emitting portion 10 on the supply side of the lighthouse 2 is supplied on the supply side. The light reflected from the outer peripheral surface of the reel hub 4 is reflected light 8 and the lighthouse 2
Reach The reflected light 8 is detected by the supply-side light receiving section 11 provided on the lighthouse 2, and the feeding of the magnetic tape 1 is stopped.

On the contrary, when the rewinding of the magnetic tape 1 from the take-up reel hub 5 through the tape guide 15 is completed and the transparent leader tape portion is reached, the leader from the take-up side light emitting section 12 of the lighthouse 2 is reached. The tape detection light 7 is reflected by the outer peripheral surface of the winding reel hub 5, and the reflected light 9 reaches the lighthouse 2. The reflected light 9 is detected by the winding side light receiving portion 13 provided on the lighthouse 2, and the magnetic tape 1 is detected.
Stop rewinding.

[0010]

As described above, the tape end detection device of the present invention has a mechanism for detecting the light reflected by the reel hub portion of the cassette. Therefore, when the magnetic tape is wound around the reel hub a plurality of times, the probability of malfunction due to holes formed in the magnetic tape during manufacturing is extremely low. If the malfunction occurs, the magnetic tape is wound around the reel hub only once, and there is no problem in practical use. Further, as compared with the conventional method, the distance from the light emitting portion to the light receiving portion becomes shorter, so that there is an effect that it is less likely to be affected by diffused reflection or refraction of light in the cassette half. In addition, the tape end can be detected at an earlier stage than the conventional method that detects the tape end near the cassette half exit, so the time margin from detecting the tape end to stopping the magnetic tape increases. Also has.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, (a) is a plan view showing the overall configuration, and (b) is a perspective view showing in detail a lighthouse in the present embodiment.

FIG. 2 shows an example of a conventional tape end detection device,
(A) is a plan view showing the entire configuration, and (b) is a perspective view showing in detail a lighthouse in a conventional example.

[Explanation of symbols]

 1 Magnetic tape 2,27 Lighthouse 3 Cassette half 4 Supply reel hub 5 Reel reel hub 6,23 Trailer tape detection light 7,26 Leader tape detection light 8 Reflected light from supply reel hub 9 Reflection from takeup reel hub Light 10,24 Supply side light emitting part 11,21 Supply side light receiving part 12,25 Winding side light emitting part 13,22 Winding side light receiving part 14,15 Tape guide 20 Trailer tape

Claims (1)

[Claims] 1. A tape reel having a reel hub made of a material having a reflectance higher than that of a magnetic tape surface, a light emitting portion and a light receiving portion directed toward the center of rotation of the reel hub, and receiving light reflected from the reel hub. And a lighthouse for detecting.