JPH064405Y2 - Cassette type magnetic head demagnetizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a degaussing device for a cassette-type magnetic head, and when one of the hubs opposite to each other in the cassette case is driven and rotated, the power generation unit is activated. The demagnetizing head is driven by the electromotive force.

A magnetic head for recording / playback such as a tape recorder is magnetized due to long-term use and causes deterioration in recording / playback characteristics.
It is necessary to perform degaussing regularly. For this reason, there has already been proposed a degaussing device incorporated in a cassette case so as to be easily handled. FIG. 5 shows a conventional degaussing device for a cassette-type magnetic head of this type. The degaussing is held in the recording / reproducing magnetic head insertion window 2a of the cassette case 1a by a spring member 3a so that the back of the degausser is elastically held. When the head 4a is provided, and the degaussing head 4a is retracted by being pressed by the magnetic head 5a of the tape recorder,
The limit switch 6a installed on the back of the spring material 3a is closed to discharge the power supply battery 7a such as a button battery, and the degaussing circuit wired to the wiring board 9a is driven to generate an alternating tapering magnetic field in the degaussing head 4a. The magnetic field of the magnetic head 5a is erased. However, this type of conventional device requires the power supply battery 7a and must be replaced when the power supply battery 7a is exhausted, and it is often used without noticing that the life of the power supply battery 7a has expired. It was Especially when the voltage of the power supply battery 7a is low, a sufficient alternating magnetic field cannot be generated, and the magnetic head 5a on the recording / reproducing apparatus side tends to be magnetized in the opposite direction. Moreover, since the limit switch 6a must be installed, there are many failures, and the degaussing head 4
Since the lever 8a of the limit switch 6a is in contact with the spring member 3a that holds the spring member 3a, the spring member 3a tends to be distorted.
For this reason, there is a drawback that the degaussing head 4a is inclined and the contact with the magnetic head 5a is incomplete.

In view of the above points, the present invention was made for the purpose of providing a degaussing device for a cassette-type magnetic head that does not require a switch device such as a power supply battery and a limit switch. One of the hubs is provided with a rotor that rotates in conjunction with the rotation of one of the hubs, and an endless belt is stretched over both of the hubs. When any one of the hubs is driven and rotated by the rotary shaft of the recording / reproducing device side, the power generation section is operated to drive the degaussing head by the electromotive force thereof to erase the magnetization of the magnetic head. It was done. Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, reference numeral 1 denotes a cassette case having the same size and shape as a Philips compact cassette, and two hubs 2 and 3 are rotatably arranged inside the cassette case. An endless belt 10 made of a rubber belt is stretched over the belt 3.

Reference numeral 4 denotes a power generation unit, which includes a ring-shaped stator 5 installed on the bottom plate of the cassette case 1 and a ring-shaped rotor 6 rotatably mounted on the stator 5 (second). Figure,
(See also Fig. 3). Reference numeral 21 is a fixing rib of the stator 5. The one hub 2 is rotated in the center of the power generation part 4 by engaging the protrusions 7, 7 protruding on the peripheral surface of the hub 2 with the recesses 8, 8 formed in the inner peripheral edge of the rotor 6 by notching. When the hub 2 rotates, the rotor 6 rotates in conjunction with the hub 2 and the power generation unit 4 operates. Reference numeral 9 is a protrusion provided on the outer peripheral edge of the bottom surface of the rotor 6, and the protrusion 9 is grounded on the upper surface of the stator 5. Reference numeral 11 denotes an insertion window of the magnetic head 12 opened in the center of the front surface of the cassette case 1, and a degaussing head 13 is arranged at the rear of the insertion window 11. The degaussing head 13 returns its back surface to the spring 14
It is elastically held so that it can move forward and backward, and is slightly pushed back by the front surface of the magnetic head 12 entering through the insertion window 11 and slightly elastically contacts the magnetic head 12. Denoted at 15 is a wiring board disposed on the side of the cassette case 1. A degaussing circuit is wired on the board 15, and the power generation section 4 and the degaussing head 13 are connected to the degaussing circuit. 16, 1
6 is a rotary shaft on the recording rehabilitation device side, and 20 is a drive display light emitting element.

FIG. 4 shows a degaussing circuit wired on the wiring board 15. The output of the power generation section 4 charges a large-capacity capacitor 17, and when the capacitor 17 is fully charged, the switching circuit 18 is activated to operate the capacitor 17 The electric charges charged in the magnetic head 12 are discharged to the oscillation circuit 19, and the oscillation of the oscillation circuit 19 causes an alternating and gradually decreasing magnetic field in the degaussing head 13 to erase the magnetization of the magnetic head 12. The present apparatus has the above-mentioned configuration, and the handling operation will be described next.

When the cassette case 1 is set in the recording rehabilitation device, the rotary shafts 16 and 16 are fitted into the hubs 2 and 3. Next, when the play button is operated, the magnetic head 12 enters through the insertion window 11 and makes a light elastic contact with the front surface of the degaussing head 13, so that the rotating shaft 1
One of the rotation shafts 16 and 16 serves as a drive shaft and rotates. Here, when the rotating shaft 16 on the hub 2 side is driven and rotated, the hub 2 rotates, and the rotation is also transmitted to the driven side hub 3 through the endless belt 10, and the hub 3 also rotates at the same time. When the hub 2 rotates, the rotor 6 of the power generation unit 4 rotates on the stator 5 together with the hub 2, and an electromotive force is generated in the power generation unit 4 so that its output is gradually charged in the capacitor 17. When the capacitor 17 is charged to a predetermined voltage sufficient to drive the oscillation circuit 19, the switching circuit 18 detects this and switches and connects to the oscillation circuit 19, and the discharge current of the capacitor 17 causes the oscillation circuit 19 to oscillate. An alternating tapering magnetic field is generated in the degaussing head 13 to erase the magnetism of the magnetic head 12. The above operation is similarly performed when the play button on the reverse side is operated to drive and rotate the other hub 3.
That is, when the rotating shaft 16 on the hub 3 side is driven and rotated to rotate the hub 3, the rotation is transmitted to the driven hub 2 via the endless belt 10, and the hub 2 also rotates and the power generation section 4 When the magnetic head 12 is activated, an alternating tapering magnetic field is generated in the degaussing head 13 by the same operation as described above, and the magnetic head 12 is demagnetized. As described above, since the present device has the endless belt 10 on both the hubs 2 and 3, no matter which hub 2 or 3 among the hubs 2 and 3 is driven and rotated, the power generation unit 4 is operated. The degaussing circuit can be driven by the electromotive force to degauss the magnetic head 12. If the hub 2 and the hub 3 have the same diameter, the hubs 2 and 3 always rotate at a constant speed, and the degaussing operation can be performed more stably. Further, if the endless belt 10 is stretched and both hubs 2 and 3 are rotated together, there is an advantage that it can be applied to an auto-stop recording / reproducing apparatus of a type that detects the rotational speed on the driven side.

Although the above embodiment has been described by taking as an example the case where it is applied to the cassette case 1 having the same size and shape as the Philips compact cassette, the present invention can be applied to the cassette case having other shapes and sizes such as a micro cassette.

As described above, the degaussing device for the cassette type magnetic head according to the present invention includes the rotor 6 that rotates in association with the rotation of the hub 2 of the hubs 2 and 3 that are provided inside the cassette case 1. The power generation unit 4, a power storage unit 17 that stores power by the output of the power generation unit 4, a switching circuit 18 that switches and connects the power storage unit 17 to an oscillation circuit 19, and the oscillation circuit 1 described above.
9 and a degaussing head 13 connected to the hub 9. Since the endless belt 10 is stretched over the hubs 2 and 3, the switching device such as a power battery or a limit switch is unnecessary, and the hubs 2 and 3 are not required. There are various effects such that the degaussing operation can be performed by driving and rotating any of the hubs 2 and 3 of the three, and the hub can also be used in an auto-stop recording / reproducing apparatus.

[Brief description of drawings]

1 shows an embodiment of the present invention. FIG. 1 is a plan view of a degaussing device for a cassette type magnetic head, FIG. 2 is a partial sectional view, FIG. 3 is a partial perspective view, and FIG. 4 is a degaussing device. A circuit wiring diagram and FIG. 5 are plan views of a conventional one. 1 ... Cassette case, 2, 3 ... Hub 4 ... Power generation section, 6 ... Rotor 10 ... Endless band, 13 ... Demagnetization head 17 ... Capacitor as power storage section 18 ... Switching circuit 19 ... Oscillator circuit

Claims (1)

[Scope of utility model registration request] 1. A hub 2, which is opposed to the inside of a cassette case 1.
3, a power generation unit 4 including a rotor 6 that rotates in association with rotation of one hub 2, a power storage unit 17 that stores power by the output of the power generation unit 4, and the power storage unit 17 is switched to an oscillation circuit 19. A degaussing device for a cassette type magnetic head, comprising: a switching circuit 18 to be connected; and a degaussing head 13 connected to the oscillating circuit 19, wherein an endless band 10 is stretched over the hubs 2 and 3. .