JPS6319926Y2 - - Google Patents

Description

[Detailed description of the invention] This invention detects the leader tape connected to the magnetic tape by transmitting light, and detects the end of the magnetic tape in the tape recorder, automatically stops the tape recorder, and reverses the magnetic tape in the tape recorder. In order to change the operation such as reversing the direction of the tape,
The present invention relates to a magnetic head equipped with optical position detection means.

In conventional cassette tape recorders,
The stop of the reel stand at the end of the tape was detected by the tension of the tape, and operations such as automatic stop and reversal were performed, but this method usually requires a long time for the head to be in contact with the leader tape. There was a drawback that recording and playback would stop after about 10 seconds. There is also a method of electrically detecting this by pasting a metal foil on the tape or leader tape, but this method has the disadvantage of requiring a metal foil to be pasted on the tape each time. In addition, the method of recording and detecting the auto-reparse signal requires a circuit as a signal source, an amplifier, a filter, etc. to detect the auto-reverse signal, and is not only cumbersome to handle.
It has the disadvantage of being disadvantageous in terms of space and cost.

Therefore, in order to improve the above-mentioned drawbacks of the conventional art, the present applicant has developed a system for the reference pin that is inserted into the reference hole of the cassette half in which the magnetic tape is stored in the embodiment of the cassette tape recorder, and for this reference pin. A light emitting element such as a light emitting diode and a photoreceptor such as a phototransistor are arranged at positions facing each other across the magnetic tape, and the light emitting element such as a light emitting element is received by the photoreceptor via the leader tape, thereby forming the terminal end of the magnetic tape. In order to perform operation switching such as detection and direction reversal, the magnetic tape position detection device and the photoreceptor or emitter of this type of optical position detection device are used for magnetic tape recording, direction reversal, etc.
We have proposed a magnetic head that has different functions housed within a magnetic head that performs reproduction and erasing.

FIGS. 1 and 2 show an example of the magnetic head proposed above, and the erasing head 1 is formed so that it can be inserted into a small window (not shown) provided next to the erasing head insertion window of the cassette case. A light emitting body or a light receiving body is provided in each reference pin 2 provided on the table deck facing this small window, and a transparent leader tape 3 is passed between these.
is configured to detect. That is, a transparent light guide portion 4 is located at a position away from the front gap portion of the erasing head 1 and in contact with the tape 3 to direct light from a light emitter 5 provided in a reference pin 2 (described later) into the erasing head 1. The erasing head 1 is integrally molded to guide the erased photoreceptor 6. On the other hand, within the reference pin 2, a minute light emitter 5, such as a light emitting diode, is provided facing the light guide portion 4 of the erasing head 1. A lead wire (not shown) of the photoreceptor 6 is connected to a terminal 7 fixed to the rear of the erasing head 1 to reach an electrical circuit (not shown) in the tape deck. The lead wire of the micro light emitter 5 is introduced into the tape deck from the bottom of the reference pin 2. The photoreceptor 6 is composed of photoelectric elements such as cadmium sulfide, photodiodes, phototransistors, etc., and a light guide is provided in a dummy portion of the erase head 1 where the erasing magnetic field generating coil 8 does not exist, so as to face the light guide portion 4. It is integrally molded or glued together with part 4 within erasing head 1. In the figure, the tip of the core part 9 is placed in parallel with the light guide part 4 and in front of the erasing head 1, and the rear part is inserted into the erasing magnetic field generating coil 8, so that the function as an erasing head is maintained. .

By the way, in the magnetic head housing the optical system for position detection proposed above, in order to detect the position of the magnetic tape, the optical system (particularly the light receiving element and the light emitting element) must be accurate with respect to the sliding position of the magnetic tape. It must be regulated and fixed in a certain position.

Since the optical element 5 placed on the reference pin 2 is formed on a fixed object called the reference pin 2, the position can be relatively easily controlled relative to the sliding position of the magnetic tape. Many difficult problems exist when it comes to optical elements 6 housed within the head.

This invention has been developed in view of the above points, and its purpose is to provide a structure for accurately regulating the position of an optical element housed in a magnetic head.

Hereinafter, this invention will be explained in detail with reference to embodiments and drawings.

The magnetic head described below is applied to a small window erasing head used in a cassette tape recorder, but it can also be applied to other magnetic heads for recording and reproducing.

Figures 3a, b, and c are views showing a plane, a cross section, and a side view of a holder used in a magnetic head.
In the figure, reference numeral 11 denotes a die-cast holder made of a non-magnetic material such as zinc alloy, which has a substantially U-shaped cross section with a large opening in one direction.
A, openings 11B and 11C are formed on surfaces perpendicular to and facing the opening 11A, respectively. Note that the opening 11A is
After the components constituting the magnetic head are attached to 1, it is closed with a lid (not shown) made of a non-magnetic material, and the opening 11B is located on the back side of the magnetic head where lead wires and the like are arranged. , and further opening 1
1C is one in which a magnetic core and a light guide portion to which light is guided are formed. Reference numeral 111 denotes a pair of slits provided on opposing walls of the holder 11 formed in a U-shape.
11 and 111 to have an appropriate depth so as to sandwich and fix the electrode extraction substrate therebetween. 112
is a pedestal on which an optical element such as a light receiving element is placed; FIG. 3b shows a cross-sectional view taken along line A-A in FIG.
As shown in , a cross-shaped slit 112a is formed integrally with the holder 11, which has approximately the same shape as the half-section of the optical element (a semicircle in the figure), and a cross-shaped slit 112a is formed on the surface on which the optical element is placed. ing. 113 is a protrusion to be inserted into a small window (not shown) of the cassette half, and 114 is a protrusion that is inserted into the holder 11 to attach the magnetic head to a head plate (not shown).
It is a threaded hole in the hole.

Next, using the holder 11 configured as described above, each part of the magnetic head is assembled into a fourth state.
Shown in Figures a and b. In the figure, reference numeral 12 denotes a lid of the holder 11, which is used to close the holder 11 by applying adhesive after each component described below is housed and fixed. 6 is the cradle 11 of the holder 11
2 is a light receiving element such as a phototransistor placed on the pedestal 112, and is fixed with adhesive injected into the slit 112a of the pedestal 112. Reference numeral 9 denotes a magnetic core around which a coil 8 is wound, and is formed linearly with respect to the direction perpendicular to the plane of the sliding surface of the magnetic tape that slides on the magnetic gap. Here, the perpendicular direction of the sliding surface is a surface perpendicular to the direction in which the magnetic gap of the magnetic core 9 is formed, and is the PP plane in the figure. In addition, the magnetic core 9 uses different magnetic materials in the part where the coil 8 is wound and the part where the magnetic gap is formed, with ferrite being used on the side where the coil 8 is wound, and a thin ribbon on the side where the magnetic gap is formed. Each uses a Sendust laminated core. Reference numeral 13 denotes an insulating electrode extraction board on which the required number of electrode lead wires 7a and 7b are provided in advance, and is clamped and fixed in a pair of slits 111 formed in the wall of the U-shaped holder 11. has been done.
A dummy member 14 is made of a transparent and wear-resistant material, such as glass. Reference numeral 15 denotes a light guide section formed of a light guide material such as a prism or a glass fiber, and this light guide section passes from the sliding surface of the magnetic tape to the light guide section of the holder 11 so as to reflect the incident light at right angles to one end. 4, the light is guided to the light receiving element 6 in a non-linear shape.

The erasing head 1 configured as described above and the tape running position sandwiched between the erasing head 1 and the reference pin located opposite to the erasing head 1, each having a transparent reader by an optical system provided with a minute light emitting element or a light receiving element. By detecting the tape, automatic stopping at the end of the tape, no recording at the time of automatic reversal operation change, and shortening of playback time are possible.

In the above embodiments, an erasing head is used as a magnetic head that houses an optical system. However, it is of course possible to use a magnetic head that performs playback or recording.

Furthermore, although the optical element housed in the magnetic head has been described using a light receiving element as an example, it may also be a light emitting element.

Further, the holder itself may be used as a case for the magnetic head, or the outside may be coated with resin or the like to form a case.

As explained above, this invention is a magnetic head that houses an optical element that detects the position of a magnetic tape, and the optical element is mounted on a pedestal that is integrally formed with a holder that securely holds the magnetic core. Since the configuration is such that it is placed and fixed, the positional relationship with the light guide is accurate, and the optical element does not move due to vibration etc., and the magnetic tape position can be reliably determined with a simple configuration. Photodetection is performed.

[Brief description of the drawings]

FIGS. 1 and 2 show partially cutaway plan and side sectional views of a magnetic head housing an optical magnetic tape position detection mechanism previously proposed by the same applicant, and FIGS. 3a, b, and c is a plan view of the holder according to this invention,
A sectional view taken along line A--A in a plan view and a side view are shown, respectively, and FIGS. 4a and 4b show a plan view and a side view of the magnetic head according to this invention. 11...Holder, 11A...Opening, 9...
Magnetic core, 112... cradle, 6... light receiving (optics)
element.

Claims (1)

[Scope of utility model registration request] The holder has an opening in at least one direction and holds the magnetic core, and the holder is integrally provided with a pedestal for mounting and fixing an optical element for detecting the position of the magnetic tape stored in the magnetic head body. A magnetic head characterized by: