JPS6017093Y2 - cassette - Google Patents

Description

[Detailed description of the invention] The present invention is a cassette formed of upper and lower flat plates and side plates, in which a flexible disc-shaped recording medium such as a magnetic disk is rotatably housed in the flat plate. The flat plate is provided with an air inlet corresponding to the center of the recording medium and a head insertion hole for bringing a recording or reproducing head into contact with the recording medium, and the cassette is installed in a recording/reproducing device. A recording or reproducing head such as a magnetic head is brought into contact with a recording medium, and video signals, etc. can be recorded or reproduced by moving the head in the radial direction of the recording medium while rotating the recording medium. The present invention relates to a cassette made of such a material.

Conventional cassettes of this kind are already known as shown in Figures 1 and 2, and these cassettes are designed to record or reproduce video signals etc. using the magnetic recording/reproducing device shown in Figure 3. is being done.

The cassette 1 in this conventional example has a pair of upper and lower flat plates 2a,
2b and the side plate 3 form a S゛ rectangle and are configured as a very thin housing, and a circular hollow part 4 is formed inside the side plate 3, and a flexible part is provided in the circular hollow part 4. A magnetic disk 5 is housed therein.

The magnetic disk 5 has magnetic surfaces 5a and 5b formed on both upper and lower surfaces, and a disk mounting hole 6 is formed in the center thereof.

The upper and lower flat plates 2a and 2b of the cassette 1 have air inflow holes 7 that are integrated into the upper and lower parts so as to correspond to the disk mounting holes 6.
a.

7b also includes air inflow holes 8a and 8b at, for example, four locations around the circular hollow portion 4, and a pair of upper and lower head insertion holes 9 that are long and extend in the radial direction of the circular hollow portion 4.
a and 9b are formed respectively.

This cassette 1 is installed in a predetermined position of the magnetic recording/reproducing device 11 by a cassette guide 12, and the magnetic disk 5 is attached to the boss 13 and the bubble 1 at the disk mounting hole 6 portion.
The head insertion hole 9 on the lower side of the cassette 1
A magnetic head 16 is inserted into b, and this magnetic head 16
is brought into contact with the lower magnetic surface 5b of the magnetic disk 5.

In the cassette device state, the disk rotating shaft 15 is rotated by a drive source such as the motor 17, thereby rotating the magnetic disk 5 in the cassette 1, and the magnetic head 16 is rotated in the radial direction of the magnetic disk 5. It is configured such that the desired recording or reproduction is performed.

By the way, in this conventional example, when the magnetic disk 5 is rotated at a constant angular velocity, air is dragged by the magnetic disk 5 in the circular hollow part 4 of the cassette 1, and the magnetic disk 5 is
A swirling airflow occurs from the inner circumference to the outer circumference.

This swirling airflow flows out of the cassette 1 through the air outflow holes 8a and 8b in the periphery of the circular hollow part 4, but the swirling airflow also flows through the pair of vertically opposing head insertion holes 9a and 9b. It flows out of the cassette 1 through both head insertion holes 9av9b.

Then, in the inner circumferential flow from these head insertion holes 9a and 9b, that is, upstream of the swirling airflow, the swirling airflow becomes a stable region, and the reference surface 19a of the cassette 1 [However, when the cassette 1 is installed upside down, the reference surface 19a] The magnetic north disk 5 rotates smoothly along the reference surface 19a with an air gap of approximately 500 microns or less maintained between the surface 19a] and the magnetic surface 5aC or 5b). Since the swirling airflow becomes unstable at a position near , the contact of the magnetic disk 5 with the magnetic head 16 becomes poor, which adversely affects electromagnetic characteristics and other various characteristics.

Especially when the groove width of the head insertion holes 9a and 9b is wide (2 to 3
771771) causes significant turbulence in the air flow,
This causes a change in the dynamic bending shape of the magnetic disk or induces vibration, and the contact of the magnetic disk 5 against the magnetic head 16 becomes very poor.

Further, the fluid pressure applied to both magnetic surfaces 5a and 5b in the vicinity of the magnetic head 16 is expressed by the following equation due to the presence of both head insertion holes 9a and 9b.

(However, pt=pressure on the magnetic surface 5a side, P2=pressure on the magnetic surface 5b side, Pa=atmospheric pressure) P1=P2L:Pa Therefore, in order to ensure that the magnetic disk 5 hits the magnetic head 16, it is indicated by arrow A in FIG. No matter how much the magnetic head 16 is pushed out, since the outer periphery of the flexible magnetic disk 5 is a free end, the magnetic surface 5b escapes in the direction of arrow A, making it impossible to obtain a good contact. I can't.

In the worst case, the head insertion hole 9a (however, the cassette 1
If the magnetic disk 5 is installed upside down, the magnetic surface 5a will come into contact with the edge (corner) of the head insertion hole 9b, creating the risk of accidentally damaging the magnetic disk 5.

The present invention seeks to provide a cassette capable of correcting the above-mentioned deficiencies.

That is, the present invention is a cassette formed of upper and lower flat plates and side plates, in which a flexible disk-shaped recording medium is rotatably housed between the flat plates, and a central portion of the recording medium is placed in the flat plate. In a cassette provided with a corresponding air inflow hole and a head insertion hole for bringing a recording or reproducing head into contact with the recording medium, a contact side of the head at a position on the rotational direction side of the recording medium with respect to the head. An air jet hole for blowing air toward the recording medium is provided on the flat plate on the opposite side, and the length of this air jet hole is selected to be equal to the length of the head insertion hole, and the length of this air jet hole is The width of the side facing the recording medium is 1rrr! This cassette is characterized by being made of a material selected from n or less, and when it is attached to a recording/reproducing device to perform recording or reproduction, by blowing air from a narrow air jet hole onto the rotating recording medium, Improve the contact of the recording medium against the head,
The electromagnetic properties and other properties can be significantly improved, and the negative effects of charging and dew condensation can be eliminated.

An embodiment in which the present invention is applied to a cassette type magnetic recording/reproducing device using a magnetic disk will be described below with reference to the drawings.

First, FIGS. 4 to 6 show a first embodiment of the cassette, and this cassette 21 has upper and lower flat plates 2 as in the conventional example.
2a, 22b and a side plate 23, a circular hollow part 24
A visible magnetic disk 25 having a disk mounting hole 26 in the center is housed inside.

Further, a pair of upper and lower air inflow holes 27a=27bs, four upper and lower air outlet holes 28a and 28b, and a pair of upper and lower head insertion holes 29at2sb that face each other are provided as in the conventional example.

Note that 30a and 30b are formed on the reference plane of the cassette 21.

The flexible magnetic disk 25 has magnetic surfaces 25a and 25b on both its upper and lower surfaces.

In this case, magnetic layers are usually coated on both the upper and lower surfaces of a single flexible magnetic disk base, but for example, the base material may be sandwiched from above and below with two magnetic disks with one side magnetic. It is also possible to create a structure in which the layers are stacked on top of each other.

However, the lever cassette 21 has a magnetic disk 25 at a position near the pair of head insertion holes 29a, 29b, on the opposite side of these head insertion holes 29a, 29b, and with respect to these head insertion holes 29 at 29b.
A pair of air ejection holes 32a and 32b are formed on the rotation direction side.

If the bookmarking set 21 is installed in a magnetic recording/reproducing device (to be described later) in the vertical position shown in FIG. 5, the rotating direction of the magnetic disk 25 will be in the direction of arrow B in FIG. If the magnetic disk 25 is mounted in the same direction, the rotation direction of the magnetic disk 25 will be in the direction of arrow B'.

In addition, in the drawing, the air jet holes 32a and 32b are formed as elongated holes extending parallel to the head insertion holes 29a and 29b, but in consideration of a multi-head or a cassette having multiple channels (multi-track) by movable heads, they may be made longer. For example, if the cassette is for a single track or several tracks, a cylindrical hole or a conical hole may be used.

However, in any case, it is desirable that the cross section of these air jet holes 32a, 32b has the following dimensions.

(However, a = width or diameter of the pinched part, b = width or diameter of the widened part, l = thickness of the cassette flat plate) a≦1mm b # a +0.3/ Also, Fig. 7 shows the air jet hole 32 a, 32b, which has the following shapes and dimensions.

(However, a=width or diameter, R=radius of curvature of the air inflow part) a≦■R''=0.33 In addition, with the shape of the air jet holes 32a and 32b shown in FIG. It's good to have a rounded shape.

8 to 10 show a second embodiment of the cassette, in which the pair of head insertion holes 29a
The upper and lower flat plates 22a of the cassette 21 with the w29b having a phase difference of 180° from each other.

22b and these head insertion holes 29a, 2.
The inner surface of the upper and lower flat plates 22a*22b on the opposite side from 9b,
That is, the head relief grooves 34 are formed on the reference surfaces 30a and 30b mentioned above.
The air ejection holes 32a and 32b described above are the same as those shown in FIGS. 6 and 7.

Next, a magnetic recording/reproducing device 3 using the above-mentioned cassette 21
7 will be described with reference to FIGS. 11 and 12. This magnetic recording/reproducing device 37 also includes a cassette guide 38, a boss 39, a disk rotating shaft 41 associated with a hub 40, and a magnetic head, as in the conventional example. 42, a motor 43, etc. are provided.

On the other hand, this magnetic recording and reproducing device 37 is provided with an air pump 45, an air valve (micro switch) 48 is provided in the middle of an air pipe 47 connected to an air discharge port 48, and a rectifier 49 is provided at the tip of the air pipe 47. The air jet nozzle 50 is connected to the air jet nozzle 50 through the air jet nozzle 50.

Note that 51 is a gasket provided at the tip of the nozzle 50, and 52 is a pressure gauge.

In addition, the air suction port 53 of the air pump 45 has a flow rate adjustment valve 5.
A cleaner filter 55 is connected via 4.

When the cassette 21 is installed in a predetermined position of the magnetic recording/reproducing device 37 using the cassette guide 38, the magnetic disk 25 is clamped from above and below by the boss 39 and the hub 40 at the disk mounting hole 26, as in the conventional case, and the disk rotation axis 41, a magnetic head 42 is inserted into the head insertion hole 29b on the lower side of the cassette 21, and this magnetic head 42 is brought into contact with the lower magnetic surface 25b of the magnetic disk 25.

With the cassette mounted, the disk rotating shaft 41 is rotated by a drive source such as the motor 43, thereby rotating the magnetic disk 25 in the cassette 21 in the direction of arrow B in FIG. 41 is moved in the radial direction of the magnetic disk 25 to perform desired recording or reproduction.

However, at this time, the air pump 45 is activated at the same time as the cassette 21 is attached.Air is drawn into the air pump 45 through the waist cleaner filter 55 and the flow rate regulating valve 54.

At the same time as the air pump 45 is activated, an air valve (micro switch) 48 is activated, and the air ejected from the air pump 45 passes through the air pipe 47 and passes through the rectifying device 49 to remove any turbulence in the flow before reaching the air jet nozzle 5.
Air is ejected from 0 to the air ejection hole 32a on the upper side of the cassette 21.

This jet of air is directed at a position on the rotational direction side of the magnetic disk 25 with respect to the magnetic head 42 (the rear region side of the head), and is perpendicular to the upper magnetic surface 25a of the magnetic disk 25 from a direction opposite to the contact direction of the magnetic head 42. (or at an appropriately inclined angle).

As a result, the magnetic disk 25 is reliably pressed against the magnetic head 42 by this air jet, and the contact between the magnetic disk 25 and the magnetic head 42 is very good, and the electromagnetic characteristics and other characteristics are significantly improved. However, the recording and reproducing accuracy becomes extremely high.

Although it is possible to press the magnetic disk 25 against the magnetic head 42, it is also possible to press it mechanically using a pad material or the like, but this lacks reliability due to the lifespan of the pad material.

On the other hand, as described above, the method of pressing with an air jet provides high reliability.

Furthermore, when the cassette 21 is attached to the magnetic recording/reproducing device 37, the magnetic disk 25 rotates immediately, but as the diameter of the magnetic disk 25 increases, the reference surface 37 of the cassette 21 rotates.
a.

The magnetic disk 25 may stick to the magnetic disk 30b due to electrostatic charge or may become sticky due to condensation, which not only hinders startup but also places a load on the drive motor 47.
Shorten the lifespan of 7.

However, when air is blown onto the magnetic disk 25 as described above, an air gap is created between the reference surface 30a and the magnetic disk 25, which prevents the negative effects of electrostatic charge and condensation, and easily causes a large It has the feature of being able to activate magnetic disks with a diameter of 1.

Note that when implementing the above-described magnetic recording/reproducing device 37, it is desirable that the air ejection pressure Ps satisfies the following experimental formula.

[However, C8 = arbitrary constant due to factors such as pressure drop correction of the rectifier 49 (C3≧1), Co = arbitrary constant due to factors such as cassette shape *Co” (0.05 to 0.5) XI
0' (kg/rrl) *, ρ=air density*p=0.
1229 (kg・5eC2/rrL4) *, Q = room air jet flow rate (m'/s) *, AN = cross-sectional area of tip (d),
A, = cross-sectional area at the parallel part in front of the rectifier 49 (bo),
Ps” gauge pressure (kg/bo) *However, in the As part*
] P, = Recruitment C(-Q-)'-(i)2 ZA) J P3 = C(2x CB The embodiments of the present invention have been described above, and the present invention is a magnetic recording and reproducing apparatus using a magnetic disk. Recording and reproducing devices that perform various recording and reproducing methods using flexible disk-shaped recording media, including but not limited to cassettes for use with cassettes, such as those that perform reproducing by electrically detecting changes in capacitance. It is applicable to a wide range of cassettes.

As mentioned above, when the cassette of the present invention is attached to a recording/reproducing device for recording or reproducing, the air generated as the recording medium rotates is caused to flow toward the periphery of the recording medium from the air inlet hole in the center. In a cassette designed to ensure stable rotation of the recording medium, when recording or reproducing the same, the length of the head insertion hole provided in the flat plate of the cassette is equal to S, and the length of the head insertion hole on the side facing the recording medium is The width is 1rIr! ft or less and is provided in a flat plate, air is delivered to the rotating recording medium at a position on the rotational direction side of the recording medium with respect to the head and on the opposite side from the contact side of the head. The spraying is what you get.

Therefore, according to the cassette of the present invention, when recording or reproducing, the recording medium can rotate stably within the cassette, and it also makes good contact with the head, significantly improving electromagnetic characteristics and other various characteristics. Recording and reproducing accuracy can be made extremely high.

Moreover, it not only eliminates the negative effects of charging and dew condensation, but also eliminates the need to consider problems such as the lifespan of the pad material (as in cases where the recording medium is pressed using a pad material, etc.), making it highly reliable. .

[Brief explanation of the drawing]

Figure 1 is a plan view showing a conventional cassette using a magnetic disk, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a sectional view of the
1 is a sectional view of a conventional magnetic recording/reproducing device using the cassette shown in the figure. 4 to 12 show an embodiment in which the present invention is applied to a cassette-type magnetic recording and reproducing device using a magnetic disk, and FIG. 4 is a plan view showing the first embodiment of the cassette; Figure 5 is a sectional view taken along line V-■ in Figure 4, and Figure 6 is a cross-sectional view of Figure 4 V.
FIG. 7 is a sectional view similar to FIG. 6 showing a modified example of the air jet hole, FIG. 8 is a plan view showing a second embodiment of the cassette, and FIG. Figure 8 is a cross-sectional view taken along the line IX-IX, Figure 10 is an enlarged cross-sectional view taken along the line X-X of Figure 8, Figure 11 is a cross-sectional view showing an embodiment of a magnetic recording/reproducing device, and Figure 12 is a cross-sectional view of the air relative to the magnetic disk. This is an enlarged cross-sectional view of the main parts to explain the situation. Also, in the symbols used in the drawings, 21 is a cassette;
25 is a magnetic disk, 29 a, 29 b are head insertion holes, 32 a, 32 b are air ejection holes, 37 is a magnetic recording/reproducing device, 42 is a magnetic head, 45 is an air pump, 50
is an air jet nozzle.

Claims (1)

[Scope of utility model registration request] The cassette is formed of upper and lower flat plates and side plates, and a flexible disc-shaped recording medium is rotatably stored between the flat plates, and the flat plate has an air inflow hole corresponding to the center of the recording medium. In a cassette provided with a head insertion hole for bringing a recording or reproducing head into contact with the recording medium, a position on the rotational direction side of the recording medium with respect to the head and on the opposite side from the contact side of the head. A flat plate is provided with an air jet hole for blowing air toward the recording medium, and the length of this air jet hole is selected to be equal to the length of the head insertion hole, and the length of the air jet hole is selected to be equal to the length of the head insertion hole. A cassette characterized in that the width of the facing side is selected to be 1 mm or less.