JPH0435805B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a demagnetizer that demagnetizes a magnetic head in a tape recorder or a magnetic tape playback device.

[Conventional technology]

Normal tape recorders and recently popular portable magnetic tape playback devices can become damaged if used for a long period of time.
The generated magnetic field tends to magnetize the magnetic head and deteriorate the recording and playback characteristics, so it is necessary to demagnetize the head at regular intervals. Conventionally, in order to facilitate the demagnetization of the magnetic head in a cassette type tape recorder, a case 101 of the same standard as a Phillips type compact cassette is used, as shown in FIG.
A degaussing signal generating circuit 102 is incorporated therein, and a degaussing head 104 is slidably disposed in correspondence with the magnetic head insertion window 103. At the rear end of the degaussing head 104, a wire spring 1 is attached at both ends to the case 101.
A degaussing device has been proposed in which a switch 106 is provided at a laterally offset position behind the degaussing head 104, and the switch 106 is brought into contact with the center of the degaussing head 105 and turns on and off in conjunction with the deformation of the wire spring 105 caused by the movement of the head 104.
Such a demagnetizer can be used for normal tape playback operations, i.e.
After the case 101 is properly set in the tape recorder, simply press the play button and the magnetic head will push the demagnetizing head 104 backwards, turning on the switch 106 and activating the degaussing circuit 102, automatically deactivating the magnetic head. The magnetic head can be easily demagnetized without requiring any skill in the demagnetizing operation.

[Problem that the invention seeks to solve]

However, degaussing of the characteristics of the degaussing head 104 occurs not only due to magnetization but also due to magnetic powder contamination on the surface of the head, and in the conventional demagnetizer described above, cleaning of the head surface had to be performed as a separate operation. .

Therefore, simply combining the structure of the cleaning cassette, which consists of rewinding the cleaning tape and adjusting it between the take-up reels, with the conventional demagnetizer, will not work.
Since the cleaning tape crosses the front tape path of the cassette main case, it is difficult to open and close the switch from the outside, and it is also difficult to obtain a space to accommodate the pair of reels.

[Means for solving problems]

This invention has been made in view of the above circumstances, and includes a tape recorder rotation shaft insertion hole provided in the main body case, and a rewind reel and a take-up reel that are rotationally driven by the rotation shaft inserted into the insertion hole. During this time, the cleaning tape is adjusted so that it is exposed on the tape path at the front of the main body case, and a degaussing head that generates an alternating magnetic field is installed behind the cleaning tape, facing the recording/reproducing head of the tape recorder. At the same time, a degaussing signal generation circuit board that supplies a degaussing signal to the degaussing head is attached to the rear of the main body case, and a part of the degaussing signal generating circuit board is connected between the rewind reel and the take-up reel. and extends toward the degaussing head,
By disposing a switch that opens and closes as the degaussing head advances and retreats in this extension, the degaussing function component and the cleaning function component can be efficiently accommodated, the degaussing function switch can be operated reliably, and the cleaning function can be reliably operated. This allows the tape to run smoothly.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In Figures 1 to 3, the main body case 8 is of the same standard as the Phillips-type compact cassette.
consists of an upper case 8a and a lower case 8b made of synthetic resin, which are arranged in a lid-like manner, and the upper and lower cases 8a, 8b
The rotary shaft insertion hole 1 of the tape recorder is inserted through the
1 and 11, and a rewinding reel 2 and a take-up 3 are connected to the rotation shaft (not shown) inwardly of the main body case 8, coaxially with the insertion holes 11 and 11.
It is rotatably arranged so as to be rotationally driven by. A liquid-absorbing cleaning tape 4 is arranged between the reels 11 and 11 so that it is exposed in the tape path at the front of the main body case 8, and the cleaning tape 4 is connected to guide pins 5 and A head insertion hole 10 and a pinch roller insertion hole 20, 20 are opened on the front surface of the main body case 8 through the liquid supply parts 6, 6 in the same manner as in commercially available compact cassettes.
It is conveyed along openings such as. The liquid supply parts 6, 6 are made of felt or the like with good water retention,
They are disposed at two locations on both ends of the front surface of the main body case 8, and are in constant contact with the inner surface of the cleaning tape 4. Further, a liquid supply port 12 is formed in the upper case 8a at a position corresponding to the liquid supply parts 6, 6, so that a special liquid can be supplied to the liquid supply parts 6, 6 from the outside.

Furthermore, the main body case 8 includes a degaussing signal generation circuit board 13 that generates an attenuated alternating voltage, and a battery 9 such as a button-type mercury battery that supplies power to the circuit board 13. A degaussing head 21 that converts the electrical signal generated by the degaussing signal generating circuit board 13 into a magnetic field is located close to the rear of the cleaning tape 4 corresponding to the head insertion hole 10 formed in the case, and is movable toward the front of the case. It is arranged.

As shown in the block diagram of FIG. 5, the degaussing signal generation circuit board 13 boosts the voltage V ₁ of the battery 9 with the DC-DC converter 14 and then converts the voltage V 2 to this output voltage V ₂ .
is applied to the switching circuit 15. The switching circuit 15 is a transistor switch that is preset to be turned on when the input voltage V ₂ reaches a set voltage V ₂ ' of about 16V, for example, and is connected to a large capacitor 16 connected to the output side of the switching circuit 15. Transfer the voltage V ₂ '. At the same time, the switching circuit 15 is opened by sending a signal from the input side of the switching circuit 15 to the control circuit 17 through the light emitting diode 18, completely separating the DC-DC converter 14 and the capacitor 16, and the DC-DC converter 14 output voltages
_V2 , the light emitting diode 18 emits light and the battery 9
The voltage is lowered to a level low enough to indicate normality. Further connected to both ends of the capacitor 16 is a self-excited oscillation circuit 19 that generates an alternating voltage having a peak value approximately proportional to the input voltage value, like an astable multivibrator. The oscillation circuit 19 starts oscillating at the same time as the voltage V ₂ ' is transferred from the DC-DC converter 14 to the capacitor 16, but at this moment, the replenishment of current to the capacitor 16 is cut off, so the capacitor 16 continues to discharge. The oscillation circuit 19 produces a damped alternating voltage whose peak value drops with a certain time constant.
V ₃ is obtained. This voltage V ₃ is applied to the degaussing head 2
1 and is converted into a damped alternating magnetic field.

Reference numeral 22 denotes a metal plate spring whose both ends are fixedly supported within the main body case 8, and as shown in FIG. 4, one surface of the central portion thereof is in contact with the rear surface 21a of the degaussing head 21 to keep the degaussing head 21 forward at all times. It is strong.
A limit type switch 25 is disposed behind the degaussing head 21 and is fixed to the degaussing signal generating circuit board 13 so as to face the rear surface 21a of the head. This circuit board 13 is a region where the tape does not run between the unwinding reel 2 and the take-up reel 3, and extends toward the degaussing head 21 from a part thereof, and is formed in a substantially T-shape. A switch 25 is disposed in the extending portion. An operating section 26 having elasticity in the front and back direction of this switch 25
is in contact with an end portion 23a of a cut-and-raised piece 23 formed rearward at a position slightly deviated from the center of the leaf spring 22. Here, the cut and raised piece 23 is the plate spring 22 after being cut and raised.
The spring constant is set to be larger than that of the operating section 26 of the limit switch 25.

Next, we will explain the operation when cleaning and demagnetizing the magnetic head of a tape recorder using a demagnetizer with a cleaning function as described above. Just like a general compact cassette, set the tape recorder at a predetermined position and press the play button. Then, as shown in Fig. 6, the magnetic head 27 for playback and recording is inserted into the head insertion slot 1 of the main body case 8.
The cleaning tape 4 is run in a predetermined direction by the pinch roller 28 which is inserted into the main body from 0 and its tip abuts the cleaning tape 4, and whose tip enters through the pinch roller insertion hole 20 (20), and the cleaning tape 4 is moved in a predetermined direction. , 6, dust adhering to the tip of the magnetic head 27 is thoroughly wiped off by the cleaning tape 4 sufficiently impregnated with a special liquid supplied from the magnetic head 27.

At this time, the cleaning tape 4 runs while being sandwiched between the magnetic head 27 and the demagnetizing head 21, but the surface of the demagnetizing head 21 facing the magnetic head 27 is covered with a slippery cover such as a polypropylene cover. If you leave it there, it will slide better and will not interfere with driving. Further, in this device, the degaussing head 21 retreats inward to the main body case 8 against the elastic force of the leaf spring 22 due to the intrusion of the magnetic head 27 at the same time as the pressing of the playback button. Along with this, the leaf spring 22 is deformed backwards in an arch shape using its fixed ends as fulcrums, so the operating piece 26 of the switch 25 is pushed by the cut and raised piece 23 extending from the leaf spring 22. The contacts of the switch 25 are designed to close. When the entire cleaning tape 4 is wound onto the take-up reel 3 and the cleaning and degaussing operations are completed, the playing state of the tape recorder is released and the magnetic head 27 exits from the demagnetizer.
It returns to its original position by the restoring force of the operating section and the leaf spring 22.

When assembling the demagnetizer, there may be variations in the mounting position of the switch 25 relative to the signal generation circuit board 13, or if the switch 25 is mounted relative to the main body case 8.
Due to variations in the mounting position of the signal generation circuit board 13 equipped with the degaussing head 21, the set position of the switch 25 may be set closer to the rear surface 21a of the degaussing head 21 than the appropriate position, and the switch 25 may not be operated when the magnetic head 27 is inserted during use. The magnetic head 27 may be pushed further even after the movement limit of the portion 26 is exceeded (see FIG. 7a). However, in the case of the above embodiment, an elastically deformable cut-and-raised piece 23 is provided to extend from the leaf spring 22 that comes into contact with the rear surface 21a of the degaussing head 21, and the operating portion 26 of the switch 25 is operated by the end 23a of the cut-and-raised piece 23. Since the switch 25 is pressed, when the operating section 26 of the switch 25 exceeds its movement limit, the cut-and-raised piece 23 responds to the retreat of the degaussing head 21 as the magnetic head 27 enters, as shown in FIG. 7b. Since it is elastically deformed and can absorb the amount of movement of the demagnetizing head 21 by the height H of the cut and raised piece 23,
No excessive force is applied to the switch 25, the demagnetizing head 21, etc., and damage to the demagnetizing head 21 and switch 25 and damage to the magnetic head 27 can be prevented.

In addition, since the cut-and-raised piece 23 has a spring constant set larger than that of the leaf spring 22 and the operating part 26, the leaf spring 22 deforms when retreating to the normal degaussing head 21, causing the above-mentioned unexpected problem. Since it first deforms in the state of , it does not cause any problem in the operation of the switch.

In the above embodiment, the operating section 2 of the switch 25
Although the elastic body 23 for pushing 6 is formed by cutting and raising the leaf spring 22 in one piece, the invention is not limited to this, and a coil spring with a spring constant larger than that of the leaf spring can be separately attached to the restoring leaf spring. It may be fixed and the end thereof may be brought into contact with the operating body of the switch.

〔Effect of the invention〕

As explained above, the present invention provides the main body case 8
The rotating shaft insertion holes 11, 11 of the tape recorder are opened in the tape recorder, and the main body case 8 is placed between the rewind reel 2 and the take-up reel 3, which are rotationally driven by the rotating shafts inserted into the insertion holes 11, 11. The cleaning tape 4 is adjusted so as to be exposed in the front tape path, and behind the cleaning tape 4, a degaussing head 21 that generates an alternating magnetic field is arranged so as to be movable back and forth, facing the recording/reproducing head of the tape recorder. At the same time, the degaussing head 21 is installed at the rear of the main body case 8.
Degaussing signal generation circuit board 13 that supplies a degaussing signal to
is attached and extends from a part of the degaussing signal generation circuit board 13 between the unwinding reel 2 and the take-up reel 3 toward the degaussing head 21, and the degaussing head 21 moves forward and backward into this extending portion. By providing the switch 25 which is opened and closed by the switch 25, the degaussing function component and the cleaning function component can be efficiently arranged and housed in a small and thin main body case such as a compact cassette.

In particular, a circuit board 13 is housed on the rear side of the main body case 8 in order to arrange circuit components for the degaussing function, and a switch for driving and operating this circuit is connected to the rewind reel 2.
The circuit board 13 is extended to an area where the tape does not run between the take-up reel 3 and the take-up reel 3, and the switch 25 is attached to this extended portion.
This eliminates the need for connection lead wires between the degaussing head 21 and the circuit board 13, which prevents the lead wires from contacting or tangling with the tape, simplifying the wiring, and since the switch 25 is located at the rear of the degaussing head 21, the degaussing head 21 can move forward and backward reliably without meandering, and the switch 25 can also be opened and closed reliably.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of an embodiment of the present invention, Fig. 2 is an assembled perspective view of the embodiment, Fig. 3 is a partially cutaway plan view of the embodiment, and Fig. 4 is a main part of the embodiment. FIG. 5 is a block diagram showing the outline of the electric circuit of the same embodiment, FIG. 6 is a plan view showing the usage state of the same embodiment, and FIG. 7 shows the operation of the main parts in the same usage state. FIG. 8 is a plan view of the conventional example, and FIGS. 9a and 9b are explanatory diagrams showing the operation of essential parts of the conventional example. 2... Rewind reel, 3... Take-up reel, 4... Cleaning tape, 8... Main body case, 9... Power supply, 11... Insertion hole, 13... Demagnetization signal generation circuit board, 21... Demagnetization Head, 25...
...Switch.

Claims (1)

[Claims] 1. Rotating shaft insertion holes 11, 11 of the tape recorder are opened in the main body case 8, and between the rewind reel 2 and the take-up reel 3, which are rotationally driven by the rotating shafts inserted into the insertion holes 11, 11, Adjust the cleaning tape 4 so that it is exposed on the tape path at the front of the main body case 8, and
At the rear of the main body case 8, a degaussing head 21 that generates an alternating magnetic field is movably arranged opposite to the recording/reproducing head of the tape recorder, and a degaussing signal that supplies a demagnetizing signal to the degaussing head 21 is provided at the rear of the main body case 8. The generation circuit board 13 is attached, and extends from a part of the degaussing signal generation circuit board 13 between the rewinding reel 2 and the take-up reel 3 toward the degaussing head 21, and the degaussing circuit board 13 is attached to this extending portion. Head 21
A demagnetizer equipped with a switch 25 that is opened and closed by moving forward and backward.