JPS6025710Y2 - Tape sensor device - Google Patents

Description

[Detailed description of the invention] The present invention involves inserting a sensor part of a sensor block equipped with a pair of light guides into the positioning hole of the cassette when installing it in the element section, and magnetically attaching the sensor block to the sensor block. This invention relates to a tape sensor device that photoelectrically detects a tape and a translucent leader tape.

Conventionally, when detecting that the tape has reached the end and stopping or reversing tape running, the leader tape end is usually stopped at the reel hub, and when the tape reaches the end, the reel axis It detects that the rotation of the tape is stopped, and controls the running state of the tape via the tape drive mechanism.

Furthermore, when the tape reaches its end in such a state, the large tension generated between the capstan and the reel hub is sensed and controlled.

However, such conventional methods have problems such as applying a large load to the tape, making the mechanism for detecting the end of the tape complex, and making the operation unreliable.

In addition, in this conventional method, the end of the tape can be detected unless the tape is run to the end of the leader tape, one end of which is latched to the reel hub.Therefore, tape running cannot be stopped while the leader tape is being run. , it is not possible to perform the next operation such as reversal, and a situation has arisen in which the open sound (music) is interrupted during reciprocating reproduction or reciprocating recording.

Therefore, in the past, as shown in Utility Model Publication No. 48-20007, etc., a magnetic tape coated with magnetic powder and a transparent leader tape were detected photoelectrically, and the leader tape was Some devices have been considered that can immediately stop or reverse tape running by detecting this part. Since it is necessary to separately provide a reflective means such as a reflective surface wall, the cassette case must be specially processed, which requires a great deal of effort.

In addition, even in the device shown in Japanese Utility Model Publication No. 48-20008, it is not necessary to provide a reflection means by special processing on the cassette case itself, but as an alternative, a separate reflection means is provided on the positioning pin of the cassette. It was necessary to form a mirror surface as a means.

Furthermore, in Japanese Utility Model Publication No. 51-7058, it is necessary to apply a reflective film to either end of the tape by coating, vapor deposition, or pasting, so the tape had to be specially processed. .

The present invention was developed in view of the above points, and is a tape sensor device that uses the arcuate front surface of a magnetic head inserted into a small window formed in the tape exposure opening of a cassette as a reflecting means. This is what we are trying to provide.

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 in the figure is a cassette provided with positioning holes 2, 2', cap stun holes 3, 3', and an opening 4 for exposing the tape.

5 is a protective sleeve that is inserted into the positioning hole 2 of the cassette and has a window 7 formed at a position facing the tape 6 of the cassette 1; 8 and 8' are slanted ends on the upper part for letting in and out light; 8a+83' and a pair of light guides having wide end portions ab and ac' at the bottom for light entry and exit, respectively, and the pair of light guides 8 and 8' have sloped portions 8a and 5a'.
are inserted into the protective sleeve 5 through the window 7 of the protective sleeve so as to face the tape 6.

The pair of light guides 8, 8' respectively directs irradiated light from a light emitting element (to be described later) from a wide end portion 8b to an inclined end portion 8a, and directs the reflected light from an inclined end portion 8a' to a wide end portion Bb'. It is assumed that all the parts other than the inclined ends 8a and 8a' and the widened ends 8b and 8b' are mirror-finished so that they are guided to the light-receiving element.

Reference numeral 9 denotes a mounting base having a pair of recesses 9a and 9b into which the light emitting element 10 and the light receiving element 11 are fitted and held adjacent to each other so as to face the divergent ends 8b and 8b' of the bottom of each of the light guides, respectively. It is.

Reference numeral 12 designates a holding base having a wide-opening hole 12a that fits and holds the wide end portions 8b and 8b' of each of the light guides 8 and 8' with the upper part thereof protruding upward; A mounting plate having a through-hole 13a for insertion, and holding the holding pieces 5a and 5b provided at the bottom of the protective sleeve 5 together with the holding base 12 to hold the protective sleeve 5 in a state protruding from its upper surface. It is.

Therefore, the mounting base 9, the holding base 12, and the mounting plate 13 are used for the light emitting element 10, the light receiving element 11. While holding the light guides 8, 8″′, protective sleeve 5, etc., respectively, tighten the mounting screws 14.1.
4' to form a sensor block 15 as shown in FIG. 3, and then mounted on the chassis 17 with the sensor part 15 protruding into the cassette/performance section 16.

That is, the sensor block 15 is screwed onto a mounting boss 19 also provided on the chassis 17 using the mounting screw 14, with its mounting base 9 fitted onto a support boss 18 on the chassis 17.

In addition, 20 is a cap that is fitted onto the upper part of the protective sleeve 5 so that the protective sleeve 5 is not damaged or obstructed when the cassette 1 is installed in the cassette playing section 16. 21.21' are respective terminals 10a, 10b of the light emitting element 10 and light receiving element 11,
11a and llb, respectively, and the light emitting element 10
and a printed circuit board for connecting the light receiving element 11 to a photosensitive circuit (not shown), respectively.

Further, 22 is a decorative plate demarcating the cassette playing section 16;
is a printed circuit board.

Reference numeral 24 is a tape exposing opening of the cassette, which is always opposed to the sensor part 15 of the sensor block provided in the cassette playing section 16 so as to be inserted into the positioning hole 2 of the cassette 1. The erasing head 24 is placed on a head substrate (not shown) to be inserted into and removed from the small window 4a formed in the cassette 4. The erasing head 24 is inserted into the small window 4a of the cassette during playback or recording operations. the inclined end portions 8a, 8a of each light guide whose arcuate front surface is exposed through the opening 7 of the protective sleeve 7 through the tape 6;
' will be facing each other.

Therefore, as shown in FIG. 4, during reproduction when the erasing head 24 is inserted into the small window 4a of the cassette 1, a magnetic tape is run at a constant speed on the front surface of the erasing head 24 in the recording state. Sometimes, the irradiated light from the light emitting element 10 is irradiated from the inclined end 8a of one of the light guides 8 onto the front surface of the erasing head 24 with an internal force Y, but it is mostly blocked by the magnetic tape. The surface is not irradiated,
Therefore, the amount of reflected light guided to the light-receiving element 11 via the inclined end 3a' of the other light guide 8' is small, and does not reach the point where the photosensitive circuit is activated.

Next, when the magnetic tape reaches its end and the translucent leader tape is placed on the front surface of the erasing head 24, the light emitted from the light emitting element 10 is directed onto the front surface of the erasing head 24. It will be irradiated and reflected,
Therefore, the amount of reflected light introduced into the light emitting element 11 increases, leading to activation of the photosensitive circuit.

Accordingly, the mechanism control circuit can be operated in conjunction with the operation of the photosensitive circuit to perform predetermined control operations such as stopping or reversing tape running.

As is clear from FIG. 3, the inclined ends 8a, 8a' of the pair of light guides face the front surface of the erasing head 24 in a parallel state. Since the front surface is arcuate, it is very suitable for the irradiation light from one inclined end 8a to reliably enter the other inclined end 3a' through the arcuate front surface. It is reflected by

Furthermore, FIG. 5 shows the main parts of a concrete auto-reverse detection mechanism equipped with the device of the present invention. Disposed near the outgoing capstan Ca facing the head Eb, the incoming erasing head Eb and part of the sensor are disposed near the outgoing capstan Ca and the outgoing pinch roller Pa while the tape is running at a constant speed in the direction of arrow A. When the tape T between 15 and 15 moves from the magnetic tape Ta to the translucent leader tape Tb, the infrared light from the infrared receiving element 10 of the infrared sensor block 15 is transmitted, hits the return erase head Eb, and is reflected. When the reflected light enters the light-receiving element 11, a photosensitive circuit is instantly activated to reverse (reverse) the tape running.

That is, according to the device of the present invention, it is possible to perform instantaneous reversal without interrupting the sound (music), compared to the conventional method in which reversal is performed at the end of the leader tape.

In addition, Ea is an erase head for the forward path, cb is a capstan for the return path, Pb is a pinch roller for the return path, H is a 4-channel recording/playback head, and Rp is a cassette positioning pin.

Next, FIG. 6, which is an example of a photosensitive circuit for refusing, will be described.

[), Tr is the above-mentioned infrared light emitting diode as a light emitting element and a phototransistor as a light receiving element, R, .
R2 is a coupling resistor connected to the first and second input terminals of the operational amplifiers OP and AMP, R3 and R1 are load resistances of the phototransistor Tr, R5 is a voltage dividing resistor, and C is a delay capacitor.

Therefore, if the voltage generated at the emitter P1 point of the phototransistor Tr in the magnetic tape part is α (mV) (10α (mV) in the transparent tape part), then the additive amplifier o
Resistors R3 and R5 are connected to the first input terminal P2 point of pAMP.
-R5, the voltage is divided by resistors R3 and R5 to 1
A voltage of /2α (mv) is input.

On the other hand, the (, (mv) (1) voltage is directly input to the second input terminal P3 point of the operational amplifiers OP and AMP.

Therefore, when it comes to the transparent leader tape part, a voltage of 10α (mv) is generated at point P□, and the voltage of 10α (mv) is generated at point P2 of the first input end.
α (mv), the second input terminal P3 point is 10α (mv), but the delay capacitor C is connected to the second input terminal P3 point.
Because of this, there is a time lag from α(mv) to 10α(
The voltage changes to mv).

In addition, the operational amplifiers OP and APM have the first and second input terminal voltages P.
When 2<R3, the 14 output points are at L level, and R2>R
At the time of 3, 11 points are assumed to be at H level.

Therefore, as shown in FIG. 7, R2>R3 for the charging time of the capacitor C, and the operational amplifiers pP and AMP operate, and the output terminal 41 changes from the L level to the H level, generating a pulse.

Then, a mechanism control circuit or the like is operated by such a pulse to stop or reverse the tape running in a predetermined manner.

In addition, in the above explanation, the resistor R3=R5 and the first input terminal P2
The point side has a voltage division ratio of 172, but by setting R3 as a variable resistor and appropriately setting R3 = aR5 (a = l, 2, 3...), the sensitivity to the voltage difference at the P□ point can be adjusted. You can.

As described above, according to the device of the present invention, when a cassette is attached to a performance section, a part of the sensor of the sensor block equipped with a pair of light guides is inserted into the positioning hole of the cassette, and the sensor block is used to insert the sensor part into the magnetic tape. A device for photoelectrically detecting a light-transmitting leader tape, wherein each of the light guides faces the tape and has its respective end connected to an opening for exposing the tape in the cassette for light entry and exit. Since it was made to face the arcuate front surface of the magnetic head inserted into the formed small window, the translucent leader tape faced each end of the light guide at the end of the magnetic tape. In fact, such a magnetic head can be used as a reflecting means for guiding the irradiated light from the light source to the photosensitive device.

Therefore, there is no need to separately apply a reflective film to the end of the magnetic tape by coating, vapor-depositing or pasting, as in the past, or to provide a separate reflective means such as a reflective plate inside the cassette case, and the effect is reduced. It has extremely high practical value.

[Brief explanation of drawings]

The figures show the device of the present invention; Figure 1 is an enlarged view of its main parts;
The figure is an exploded perspective view of the main part, Figure 3 is a schematic front sectional view,
Fig. 4 is a schematic side sectional view of the same, Fig. 5 is a perspective view of a main part showing a specific embodiment thereof, Fig. 6 is a diagram showing one embodiment of the photosensitive circuit, and Fig. 7 is a time chart thereof. be. 1...Cassette, 2...Positioning hole,
4...Tape exposure opening, 4a...
Small window, 6... Tape, 5... Protective sleeve, 8, 8'... Light guide, 8a, 8a'...
... Slanted end, 8b, 8b'... Wide end, 9... Mounting base, 10... Light emitting element,
11... Light receiving element, 12... Holding stand,
13...Mounting plate, 15...Sensor block, 15'...Part of sensor, 16...
...Cassette performance section, 17...Chassis, 24
...Erasing head, OP, AMP...
operational amplifier.

Claims (1)

[Scope of utility model registration request] A sensor part of a sensor block equipped with a pair of light guides is inserted into the positioning hole of the cassette when it is installed in the performance section, and the sensor block photoelectrically connects the magnetic tape and the transparent leader tape of the tape. In the apparatus, each of the light guides has its respective end portion facing the tape for light entry and exit inserted into a small window formed in the tape exposure opening of the cassette. A tape sensor device characterized in that the tape sensor device is opposed to the arc-shaped front surface of a magnetic head.