JPH07320365A - Disc apparatus - Google Patents

Abstract

PURPOSE:To obtain a disc apparatus whose size can be reduced which can realize the support of a cassette holding member and a guide means with a simple construction, and can be assembled easily. CONSTITUTION:A chassis 1 is bent into a semi-rectangular shape and side plates 2 and 2 are formed on both the sides of a bottom plate. A cassette guide 87 which can hold a disc cassette inserted through the opening end of the front side of the chassis 1 is provided. A head table 30 on which a coupler to which the cassette is attached and which is driven by a motor to rotate and a magnetic head 47 are mounted, is provided on the bottom plate of the chassis 1. A plurality of guide slots 3 which are mated with rollers 90 provided on the side surfaces of the guide 87 and move the guide 87 only in a direction approximately perpendicular to the cassette insertion direction to transfer the guide 87 from a detaching position apart from the coupler to a position where the guide 87 is attached to the coupler or detached from the coupler are formed in the side plates 2 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device in which a disk-shaped recording medium is mounted for recording or reproducing.

[0002]

2. Description of the Related Art Conventionally, there has been known a disk device in which a disk-shaped recording medium such as a magnetic disk is mounted and recording or reproduction is performed on the recording medium.

This kind of apparatus is constructed such that a motor as a rotary drive unit for rotationally driving a recording medium loaded on a chassis and a head for contacting the recording medium rotated by the motor to perform recording or reproduction. Are arranged.

A holder for loading and unloading the recording medium is attached to the chassis at a position where the recording medium can be attached and detached.
It is movably arranged at a rotation drive unit and a mounting position where it can be mounted on the head, and the recording medium can be mounted by moving the holder.

[0005]

However, looking at the supporting means of the holder in this kind of apparatus, the guide groove for supporting the holder by a complicated link mechanism or for guiding the holder to the above-mentioned respective positions is formed. Since the side plate is screwed to the chassis, etc., the assembly becomes troublesome, the number of parts increases, and more space is needed for the necessary parts and mounting work. It has drawbacks such as hindering miniaturization.

The present invention has been made in view of the above circumstances, and solves the drawbacks such as hindering downsizing, and also makes it possible to realize the holder support and the guide means with a simple structure and the assembling workability. An object is to provide a good disk device.

[0007]

In order to solve the above problems, in the disk device of the present invention, the bottom plate and the both side plates are formed by bending the flat chassis in the substantially U shape on both sides thereof, and , A front chassis is formed as an open end to form a main chassis, and a holding member capable of holding a cassette containing a disk-shaped recording medium inserted from the open end of the main chassis is provided, and the bottom plate is A disc mounting unit for mounting the disc-shaped recording medium, a disc rotation drive unit for rotating the disc-shaped recording medium mounted in the disc-mounting unit, and recording on the disc-shaped recording medium mounted in the disc-mounting unit. Head means for reproducing and head moving means for moving the head means in the radial direction of the disk-shaped recording medium Is disposed on the both side plates, by engaging with an engaging portion formed on the side surface of the holding member, and moving the holding member only in a direction substantially perpendicular to the cassette insertion direction, the disc mounting portion A configuration is adopted in which a plurality of guide portions for transferring the holding member are formed from a more detached mounting position to a mounting position where the disc mounting portion is mounted, or vice versa.

[0008]

According to this structure, since the side plate having the guide portion can be directly formed on the bottom plate without providing the side plate mounting portion on the bottom plate of the chassis, the length in the device width direction can be reduced. Can be made smaller. Further, the position of the guide portion formed on the side plate can be easily defined with respect to the bottom plate provided with the disc-shaped recording medium insertion port and the disc mounting portion. Also, the bent part (side plate) of the chassis
In addition, by forming the guide portion of the holding member in advance during molding of the chassis, it is possible to realize the support and guide means of the holding member with a simple configuration. Further, since the guide portion is formed on the side plate so as to move the holding member only in the direction substantially perpendicular to the cassette inserting direction, it is not necessary to provide the side plate with the guide portion for moving the holding member in the cassette inserting direction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on the embodiments shown in the drawings.

The magnetic disk device according to the present invention is assembled with a chassis (main chassis) 1 as a reference.
The chassis 1 is configured as a U-shaped frame body having left and right side plates 2 and 2, and guide grooves 3 and 3 are formed in a position facing each side plate 2 and 2 from an upper edge toward a lower side. There is. Rollers protruding from the cassette guide side, which will be described later, are fitted into these guide grooves 3, 3.

Also, between the guide grooves 3, 3, the side plate 2,
A guide hole 4 is formed in a horizontal state at a position opposite to each other, and a guide groove 5 is also formed in a horizontal state on the front side edges of the side plates 2 and 2. A guide roller of a slide frame described later is fitted in the guide hole 4 and the guide groove 5.

On the other hand, three positioning pins 7 are provided on the bottom plate 6 of the chassis 1 with a predetermined arrangement.

These pins 7 perform vertical positioning of the cassette, which will be described later.

At one end of the chassis on the bottom plate 6, a pulse motor 8 serving as a drive source for moving the magnetic head is provided with studs 8a,
It is fixed via 8a, and in the vicinity thereof, a projecting piece 9 that cuts and raises the bottom plate 6 is projected. Through-hole 1 in protrusion 9
0 is formed, and a through hole 11 is formed in one of the side plates 2 in a state of facing the through hole 10. A guide shaft 12 that guides a head mount, which will be described later, is laterally installed using the through holes 10 and 11.

Further, on the front side of the chassis 1, another guide bar 13 is provided horizontally between the side plates 2 and 2 in parallel with the guide shaft 12.

On the other hand, a drive gear 14 is fixed to the output shaft of the pulse motor 8 on the lower side thereof, and the drive gear 14 is rotatably supported on the bottom plate 6.
It meshes with 5.

A through hole 16 is formed in a substantially central portion of the bottom plate 6, and a boss 17 for bearing a rotary drive mechanism of the magnetic disk is attached to the through hole 16.

As shown in FIG. 3, the boss 17 has a flange 17a on the outer periphery of the central portion thereof. The flange 17a is superposed on the upper surface of the bottom plate 6, and the lower portion of the boss 17 is fitted into the through hole 16 and screwed. It is fixed by 18 via the flange 17a.

A rotary shaft 20 is rotatably supported in the boss 17 through a pair of upper and lower bearings 19, 19. A collar 21 is arranged between the upper and lower bearings 19. The outer ring of each bearing 19, 19 is press-fitted into the boss 17.

A coupler 22 is fixed to the upper end of the rotary shaft 20. The coupler 22 is fitted to the center hub of the magnetic disk cassette, and a positioning pin 23 is fitted to the flange 22a so as to be able to move up and down.

The lower end of the pin 23 is fixed to the free end side of the leaf spring 24 at the lower side of the flange 22a, so that the pin 23 always has a tendency to move in the protruding direction.

A spring 25 is elastically mounted between the lower surface of the coupler 22 and the inner ring of the upper bearing 19, and by pressing the inner ring downward, a relative displacement is generated between the inner ring and the outer ring. The uniform contact between the inner and outer races and the balls is generated, and the backlash of the inner and outer races is eliminated.
I try not to cause a 0 swing.

A gear 27 is fitted and fixed to the boss 17 via a boss 28 with the cam 26 facing upward.
7 is meshed with the gear 15 and transmits the rotation of the pulse motor 8 to the head side via the cam 27. A washer 29 for tightening is fitted on the outer side of the boss 28 to prevent the cam 26 and the like from coming off.

On the other hand, the reference numeral 30 indicates a head base,
It is formed in an elongated plate shape. One end of the head base 30 is slidably fitted to the guide shaft 12 via a linear bearing 31.

The other end of the head base 30 is slidably guided by another guide shaft 13.

That is, as shown in FIG.
As shown in (C), the conical roller 3 faces downward.
A shaft 33 that rotatably supports 2 is provided in a protruding manner. A spring 34 is elastically mounted between the shaft 33 and the roller 32 to give the roller 32 a tendency to move upward.

The shaft 33 is fixed to the head base 30 side by a screw 35, and one end of a leaf spring 36 is fixed to the upper side of the head base 30 by the screw 35.

The guide shaft 1 is provided in the opening 30a formed in the head base 30 whose upper side is covered by the leaf spring 36.
A roller 37 is rotatably fitted in a state of being orthogonal to 3.

Therefore, the guide shaft 13 is elastically sandwiched between the inclined surface of the conical roller 32 and the roller 30, and is slidably attached to the guide shaft 13.

As described above, since the shafts 12 and 13 for guiding the movement of the head base 30 are mediated by the linear bearing and the bearing member utilizing the rotational friction by the rollers, the friction is extremely small, as compared with the bearing utilizing the sliding friction. The head stand can be moved much more smoothly. Therefore, the pulse motor 8 can be a small-sized, low-power, inexpensive motor.

Of course, as shown in FIG. 5B, the guide shaft 12 is guided by the bearing member 38 utilizing sliding friction, and the material of the bearing member 38 is expensive but very excellent in wear resistance. For example, if a ruby or the like is used, a cheap pulse motor can also be used.

A spring 39 is stretched between the head base 30 and the projecting piece 9 to give the head base 30 a movement habit toward the rotary shaft 20.

The head base 30 is arranged above the cam 26, and one end of a lever 40 is rotatably supported by a screw 41 on the back surface of the head base 30.

A spring 42 is stretched between the other end of the lever 40 and the head base 30.
On the other hand, the habit of turning counterclockwise in FIG. 1 is given.

A roller 44 is rotatably supported on the lower surface of the lever 41 via a pin 43, and the roller 44 is in contact with the cam surface of the cam 26.

By the way, as shown in FIG. 6, the cam 26 has a spiral and a large number of saw-toothed cam surfaces as a whole, and the sawtoothed cam portion is used, for example, when the number of tracks of the magnetic disk is 40. Has 40 cam portions corresponding thereto.

In FIG. 6, the cam portions are set so that the radius represented by the symbol R0 is the maximum radius and the radius represented by R39 is the minimum radius, and the radius from the outermost track of the magnetic disk to the innermost radius is set. The magnetic head can be moved to the track.

It is the pulse motor 8 that rotates this cam, and the rotation is transmitted through the gears 14, 15, and 27.

Actually, the pulse motor 8 is set to rotate 18 ° when one driving pulse is input to the pulse motor 8. When the pulse of the positive phase is applied, the motor rotates to the right and reverse. It rotates counterclockwise when a phase pulse is applied.

Further, when the pulse motor 8 rotates by 18 °, the gears 27 are rotated by 6 ° so that the gears 14, 15, 27 are rotated.
The gear ratio is set, and 40 cam portions having radii R0 to R39 are formed within the range of 6 °.

Therefore, the magnetic head moves by one track each time the cam rotates by 6 °, and the specific moving amount is 0.12 mm, and the total width of all 40 tracks is about 5 mm.

On the other hand, as shown in FIG. 24, an adjusting screw 45 is screwed into the bent portion 30a provided in the middle of the head base 30 in the longitudinal direction.

The tip of the adjusting screw 45 is shown in FIG.
As shown in (B), the lever 40 is in contact with the bent portion 40a formed on the side edge on the free end side, and the position of the lever 41 can be adjusted.

A rectangular opening 30b is formed in the middle of the head base 30 in the longitudinal direction, and a magnetic head 47 is disposed in this opening 30b via a support member 46.

An arc-shaped leaf spring 49 is mounted between one end of the support member 46 and a projecting piece 48 projecting from one end of the opening 30b, and the other end of the opening 30b is projected. The tip of the adjusting screw 51 screwed into the protruding piece 50 is in contact with the side edge of the supporting member 46 on the side opposite to the spring 49.

Therefore, by turning the adjusting screw 51, the position of the support member 46 and the position of the magnetic head 47 can be adjusted.

The adjusting screw 51 can correctly adjust the center of the magnetic head with respect to the center of the magnetic disk.

After the position is correctly adjusted by the adjusting screw 51, the supporting member 46 is attached by the screw 52 to the head base 30.
It is sufficient to fix it completely.

By the way, brackets 53, 53 are provided so as to project from the end of the head base 30 on the guide shaft 12 side, and one end of the pad arm 54 is freely rotatable via a pin 55 using these brackets 53. It is supported by.

A torsion coil spring 56 is wound around the pin 55 to give the pad arm 54 a habit of turning clockwise in FIG.

The tip of the pad arm 54 extends above the magnetic head 47, and an adjusting screw 57 corresponding to the magnetic head 47 is screwed to the tip of the pad arm 54. The lower end of the pad arm 54 is a pad for pressing the magnetic disk. 58 is provided.

Therefore, if the screw 57 is rotated, the pad 5
8 and the magnetic head 47, the parallelism and the pad pressure can be adjusted.

On the other hand, a control plate 59 is integrally provided on the lower side of the gear 27, and a protrusion 59a is formed on a part of the control plate 59, and a notch 59b is formed at the base of the protrusion 59a. Has been done.

Then, the bottom plate 6 is provided on the side of the control plate 59.
A lever 61 is rotatably supported above the pin 60 via a pin 60. Protrusions 61a and 61b are formed at one end of the lever 61 so as to be separated from each other by a predetermined distance.
The a and 61b are always in contact with the outer peripheral surface of the control plate 59.

The other end of the lever 61 is formed in a slender shape, and faces the upper side of a notch 6a formed at the front edge of the bottom plate 6. And the notch 6
A sensor 62 is arranged to face a. This sensor 62 is composed of, for example, a light emitting element and a light receiving element, and always receives the reflected light from the lower surface of one end of the lever 61,
The existence of is being monitored.

By the way, the following relationship exists between the mounting position of the lever 61 and the projection 59a and the cam portion of the cam 26 having the maximum radius R0.

That is, when the roller 44 reaches the cam portion having the maximum radius R0, the projection 59a is set in such a positional relationship that it can engage with the projection 61b of the lever 61.

Therefore, as shown in FIG. 6, when the roller 44 is in the cam portion having the radius R1, the protrusion 61b of the lever 61 is not in contact with the protrusion 59a, and one end of the lever 61 blocks the upper portion of the sensor 62. is there.

In this state, the protrusions 61a and 61b are in contact with the peripheral surface of the control plate 59, and the lever 61 does not rotate.

However, when the cam 26 is rotated by one extra step by the pulse motor 8, the roller 44 rides on the cam portion having the maximum radius R0, and the magnetic head 47 moves to the outermost track position together with the head base 30. Will correspond.

At this time, as shown in FIG. 7, the protrusion 59a contacts the protrusion 61b of the lever 61, the lever 61 is rotated counterclockwise in the figure, and the protrusion 61b is fitted into the notch 59b. Then, one end of the lever 61 is separated from the upper side of the sensor 62 at this time as shown in FIG. 7, the sensor 62 is turned off, and it is detected that the magnetic head has reached the outermost track.

Therefore, if the outermost track is set to 0 track and this position is surely detected by the above-mentioned mechanism, and the magnetic head is set to reach this position when the power is turned on, The head position at the time of start coincides with 0 track, and if the pulse for the pulse motor 8 is applied from this position, the head moves to the 5th track if it is 5 pulses and the 10th track if it is 10 pulses. You can choose to.

The current position of the magnetic head with respect to these pulse inputs may be stored in the memory of the digital processing system.

The specifications between the control plate 59 and the lever 61 are specifically as follows.

That is, as shown in FIG. 6, when the radius R of the control plate 59 is 15 mm and the rotation angle α of one step is 6 °, the movement distance δ of the peripheral edge of the control plate 59 is tan = 6 ° × 15 mm = 1.6 mm. .

Further, the distance B from the pin 60 of the lever 61 to the tip B = 5 mm, the distance A from the pin 60 to the rear end A = 13 m
m, the moving distance of the rear end of the lever 61 is δ ₁ , and the rotation angle is α '
Then, α '= 15/5 × 6 ° = 18, and δ ₁ ≈tan 18 ° × 13mm≈4.2mm.

Therefore, when the peripheral edge of the control plate 59 is rotated by 1.6 mm, the lever ratio of the lever 61 is 3, so that the lever 61 is rotated by about 18 °.

As a result, the outer end of the lever 61 is rotated by 4.2 mm, and if the size of the sensor 62 is 3 mm, the sensor surface can be opened and closed sufficiently.

Of course, if the sensitivity of the sensor 62 itself is increased, the movement of the protrusion 59a itself of about 1.6 mm can be sufficiently detected, but the movement of the control plate can be detected easily and inexpensively by using the lever as described above. be able to.

When such a lever is used, the control plate 61,
Therefore, since the rotation of the cam 26 can be detected outside the other parts, it is possible to obtain a detection mechanism that is less subject to spatial restrictions.

A magnetic disc cassette is attached to the coupler 22 provided at the upper end of the rotary shaft 20.

Most of the magnetic disk cassette except the center hub is made of synthetic resin.

On the other hand, the drive mechanism side of the magnetic disk is mostly metallic, so that it is affected by thermal expansion.

The details are as follows.

That is, in FIG. 24A, the rotary shaft 20
Is ₁ to the center of the magnetic head 47, that is, a certain track, the distance between the peripheral edge of the center hub 63 and the center of the rotary shaft 20 is l ₂ , and the distance from the peripheral edge of the center hub 63 to the track is l. _If l is ₃ , the l ₂ part is a metal, and the l ₃ part is a synthetic resin. Specifically, l ₁ = 20
If mm, l ₂ = 8 mm, then l ₃ is 12 mm.

On the other hand, when the distance from the center of the rotary shaft 20 to the track on the drive side is L ₁ , the contents are the distance L ₂ from the center of the rotary shaft 20 to the peripheral edge of the boss 28, and the boss 2.
8 is the total of the distance L ₃ from the peripheral edge of the cam 26 to the track and the distance L ₄ from the peripheral edge of the cam 26 to the track, and each part is made of metal.

Therefore, if L ₂ = 8 mm and L ₄ = 1.5 mm, then L ₁ = 20 mm, so L ₃ = 20-8-1.5 = 10.5 mm.

Now, if the error between L ₁ and l ₁ is set to zero at a temperature of 25 ° C., the temperature rises by 20 ° C.
When the temperature reaches 5 ° C, the following results are obtained.

That is, the linear expansion coefficient of metal is 16 × 10 ⁻⁶ mm / ° C.,
When the linear expansion coefficient of the synthetic resin film is 17 × 10 ⁻⁵ mm / ° C., l ₁ and L ₁ are as follows when they are applied to l ₁ (1 + αt) −δ.

L ₁ = l ₂ + l ₃ = (8 + 8 × 20 × 16 × 10 ^-6 ) +
(12 + 12 × 20 × 17 × 10 -5) = 20.043mm L = L 1 + L 2 + L 3 = (8 + 8 × 20 × 16 × 10 -6) + (1.5 + 1.5 × 20 × 16 × 10 - ⁶ ) + (1
0.5 + 10.5 × 20 × 16 × 10 ^-6 ) = 20.006mm That is, when the temperature rises by 20 ° C, the difference between L ₁ and l ₁ is 20.043-
20.006 = 37μm It goes out of order and the information on the magnetic disk cannot be read correctly.

Therefore, in the present invention, when the material of the cam 26 is made of synthetic resin having a coefficient of linear expansion substantially the same as that of the magnetic disk 64, L ₁ is as follows.

L ₁ = (8 + 8 × 20 × 16 × 10 ^-6 ) + (1.5 + 1.5 × 2
0 × 16 × 10 ^-5 ) + (10.5 + 10.5 × 20 × 10 ^-5 ) ＝ 20.038mm That is, the difference between L ₁ and l ₁ is 2 by changing the material of the cam.
0.043-20.038 = 5 μm.

Therefore, the influence of thermal expansion can be sufficiently reduced.

In the present invention, the central positions of the magnetic head 47 and the roller 44 can be positioned by the adjusting screw 45.

Then, the magnetic head 47 is observed by a microscope or the like.
It can be set accurately to 20mm the L ₁ while watching the position.

FIG. 24B shows that the center positions of the magnetic head and the roller 44 deviate by δ.

Further, since the cam 26 can rotate, as shown in FIG.
There is a gap of δ ₂ between and.

Therefore, when the cam 26 rotates, the boss 17,
The gaps δ ₁ and δ ₂ between 28 constantly change, and the change directly affects L ₁ .

In order to eliminate this influence, in the present invention, in order to constantly make the gap δ ₁ between the bosses 17 and 28 on the magnetic head side zero, a spring 39 is stretched between the head base 30 and the projecting piece. The head base 30 is always attracted to the boss 28 side,
Moreover, the magnetic head is set in pressure contact with one side by the spring 42 so that the position of the magnetic head does not deviate from the track.

On the other hand, the rotary shaft 20 extends below the chassis 1, and a member constituting a motor is attached to the printed circuit board 65 fixed to the lower side of the chassis 1.

That is, the coil 6 is provided on the lower surface of the printed circuit board 1.
5a is fixed by soldering.

On the other hand, a boss 66 is fixed to the lower end of the rotary shaft 20, and a dish-shaped yoke 68 and a gear 69 are fixed to the boss 66 with screws 67.

A coil 65a is formed on the upper surface of the yoke 68.
The ring-shaped permanent magnet 70 is fixed in a state of facing.

Further, one yoke is provided on the outer periphery of the yoke 68.
A non-reflection plate 71 that generates one pulse when rotated is fixed, and a sensor 72 for detecting this is fixed to the printed circuit board 65 side.

Since the yoke 68 is plated with nickel or the like, the sensor 72 including a light emitting element and a light receiving element can surely detect the non-reflective plate 71, and this signal can be used as an index signal.

On the other hand, reference numeral 73 is a sensor which is fixed to the printed circuit board 65 side and has a permanent magnet 74 and a yoke 75 which is continuous with the permanent magnet 74. The yoke 75 is near the gear 69 as shown in FIG. Is being faced with.

In FIGS. 1 and 3, reference numeral 76 is an electronic component such as LSI, and reference numeral 77 is a screw for fixing the printed circuit board 65 to the chassis 1.

By the way, the gear 69 is made of a ferrous material and has a large diameter. When the tooth tips approach the yoke 75, the magnetic flux changes and a current flows through the coil on the sensor 73 side. Can be taken out as.

The coil 65a and the permanent magnet 70 side described above constitute a motor for rotating the magnetic disk.

By the way, this motor is set to rotate once in 200 ms.

Further, in order to rotate at a constant speed without shaking during one rotation of 200 ms, 200 ms is finely divided so that accurate rotation control can be performed.

That is, since the diameter of the gear 69 is 50 mm, the module is 0.25, and the number of teeth is 200, 200 m
The rotation change by the sensor 73 is monitored at intervals of s / 200 = 1 ms.

The printed circuit board 65 is a thin insulating substrate and is fixed to the iron chassis 1, and the magnetic flux generated by energizing the coil 65a integrally provided between the chassis 1 and the yoke 68. The permanent magnet 70, and hence the yoke 68 and the gear 69 are rotated through the formed magnetic circuit.

By fixing the printed circuit board 65 to the iron chassis 1 as described above, the space between the permanent magnet and the chassis can be narrowed, and the efficiency of the magnetic circuit is improved.

Further, when the chassis 1 is made of a printed board made of iron, the thickness of the motor portion can be reduced by the thickness of the printed board 65 constituting the motor, and the number of parts can be reduced.

By the way, since the permanent magnet 70 is given a force to be attracted to the chassis 1 side, the lower bearing 1
Since the inner ring 9 is pressed upward by the boss 66, the play of the bearing 19 can be absorbed and the runout of the rotary shaft 20 together with the upper bearing 19 can be prevented.

On the other hand, since the inner and outer diameters of the boss 17 fixed to the chassis 1 side are machined at the same time on the basis of the fixing portion to the chassis 1, the inner and outer diameters can be machined to about 1 to 2 μm.

Due to this processing accuracy and the absorption of the backlash of the bearing 19, the deflection of the rotary shaft 20 including the boss 17 is 5
It can be maintained within μm.

The driving mechanism section has been described above, and then the cassette mounting mechanism section will be described.

The cassette mounting mechanism employs a structure as shown in FIGS.

That is, the reference numeral 78 in the figure is a slide frame which is formed as a frame body whose lower side and front and rear sides are opened.

The rollers 7 are provided on both side surfaces of the slide frame 78.
9 is rotatably supported, and these rollers 79 are horizontal long holes 4 formed in the side plates 2 and 2 of the chassis 1.
It is slidably and rotatably fitted inside.

Openings 78a are formed at the left and right upper corners of the slide frame 78, and the openings 78a are formed.
A protruding piece 78b is integrally provided on the upper surface of the slide frame 78 so as to pass therethrough. This protrusion 78b and chassis 1
The spring 80 between the protrusion 2a protruding from the side wall of the
Is stretched.

Therefore, the slide frame 78 is given a force in a direction projecting from the chassis 1 to the front side.

A roller 81 is rotatably supported by a projecting piece projecting from the lower ends of the both side plates of the slide frame 78, and the roller 81 is slidably movable on the chassis 1 through the roller 81.

Projection 7 projecting from one end of slide frame 78
A push button 82 is fixed to 8c.

Further, slanted long holes 83 are formed in parallel at two positions on the left and right side plates of the slide frame 78. Slide plates 84 are slidably disposed on the left and right inner side surfaces of the slide frame 78.

The slide plate 84 is formed in a rectangular shape, and its lower end is in contact with the small-diameter shaft portion 81a of the roller 81 which is in contact with the bottom plate 6 of the chassis 1.

A projection 84a is provided on the upper end of the slide plate 84.
Projecting from the slide frame 7.
It is fitted in the opening 78a of the hole 8 and serves as a guide.

A bent portion 84b which is bent inward is formed at the tip of the slide plate 84.

Further, a substantially L-shaped opening 85 is formed in the slide plate 84 at a position substantially corresponding to the long hole 83 of the slide frame 78.

Inside the tip of the slide plate 84, the protruding piece 8 is provided.
4c is provided in a protruding manner, and the protruding piece 84c and the slide frame 7 are provided.
A spring 8b is stretched between the spring 8 and the shaft 8.

By the way, below the slide frame 78, a cassette guide 87 as a holding member capable of holding the magnetic disk cassette 93 is arranged.

The cassette guide 87 is formed as a flat frame body, and rail portions 87a for guiding the cassette are formed on the left and right sides thereof.

Further, projecting pieces 88 are projectingly provided on the left and right sides of the cassette guide 87, and pins 89 are projectingly projecting on each projecting piece 88, and a roller 90 is rotatably supported by these pins 89. ing.

Each roller 90 is rotatably fitted in the slide plate 84, the opening 85 of the slide frame 78, and the elongated hole 83.

An opening 87b is formed in the center of the upper surface of the cassette guide 87, and the opening 87b is formed.
A frame 91 is integrally provided in a state of straddling b, and a hub retainer 92 is attached to the frame 91.

An opening 87c into which the magnetic head is fitted is formed on the side of the opening 87b.

The cassette mounting mechanism is composed of the three members, the slide frame 78, the slide plate 84, and the cassette guide 87 described above.

Next, the operation of the cassette mounting mechanism will be described.

Before the magnetic disk cassette 93 is mounted, the slide frame 78 is moved to the right side in FIGS. 8 and 13 by the tensile force of the spring 80.

In this state, the roller 90 is in the guide groove 3, is located at the upper end of the elongated hole 83 as shown in FIG. 13, and is on the stepped portion 85a of the L-shaped opening 85. Is located in.

That is, the roller 90 is restricted by the guide groove 3, the long hole 83, and the opening 85.

Further, the slide plate 84 is also pulled to the right side in FIG. 13 by the spring 86, and the cassette guide 87 is arranged to receive the cassette while being positioned above the step 85a.

In this state, when the cassette 93 is fitted into the rail portion 87a of the cassette guide 87, the cassette 9
3 is guided by this rail portion 87a and guided to the back.

Eventually, the tip of the cassette 93 comes into contact with the bent portion 84b at the tip of the slide plate 84, and the slide plate 84
Is moved forward against the tensile force of the spring 86.

Then, since the opening 85 also moves with the movement of the slide plate 84, it is positioned in the guide groove 3 and on the step 85a of the opening 85 as shown in FIGS. 12 (A) and 12 (C). The roller 90 that has been dropped falls to the vertical portion side of the opening portion 85, and is guided below the guide groove 3 and the vertical portion of the opening portion 85 as shown in FIGS. 12B and 12D. That is, the cassette 93 moves downward together with the cassette guide 87.

By the way, by the operation of inserting the cassette, the roller 90 is moved to the long hole 83 as shown in FIG. 12 (E).
From the state in which it was located at the upper end of the slot, it moves to the lower part of the long hole 83 shown in FIG.

During this movement, the roller 90 pushes the right side edge of the long hole 83, so that the slide frame 78 is moved to the right by a predetermined distance as shown in FIG.

When the cassette guide 87 descends together with the cassette 93 in this manner, the protrusion 7 of the positioning pin 7
The projection 7a of the pin having a
The upper end of the pin 7 fitted in 3a and having no protrusion 7a contacts the lower surface of the cassette to support and position the cassette. This state is shown in FIG.

At this time, as shown in FIG. 11, the coupler 22
Is fitted in a hub 95 at the center of the magnetic disk 94, and the pin 23 is fitted in a positioning hole 96 formed in the hub 95. The upper surface of the hub 95 is pressed by the hub retainer 92.

This mounting operation is performed while the rotary shaft 20 is rotating.

When the cassette 93 is set in this way, magnetic recording and reproduction are performed.

On the other hand, when it is desired to take out the cassette 93, the push button 82 is pushed to move the slide frame 78 forward.
Then, the peripheral edge of the slanted long hole 83 pushes the roller 90, so that the roller 90 is pushed up and the cassette guide 87 is also pushed up to return to the original position.

The cassette guide 87 rises and the roller 90
When it also rises, since it is located above the opening 85, the slide plate 84 moves to the right as shown in FIG. 13 by the tensile force of the spring 86, and the roller 90 moves to the horizontal part of the opening 85. Get on the step 85. By the operation of the slide plate 84, the bent portion 84b pushes the cassette 93, so that the cassette 93 can be pushed out from the end of the cassette guide 87 toward the front side and taken out.

By the way, the slide frame 78 and the slide plate 8
4, the cassette guide 87 is arranged inside the side plates 2 and 2 of the chassis 1 in the assembled state as shown in FIG. 15, and the rollers 79 and 79a are fitted in the long holes 4 and the notches 5. Assembling can be easily performed by fixing the side surface of the slide frame 87 with the screw 79b. The pad arm 54 may be finally attached to the head base 30 side.

By the way, a block diagram of the control circuit is shown in FIG.

The magnetic disk device according to the present invention is controlled by the computer 100. The computer 100 and the magnetic disk device side are connected by electric wires, and when the input and output lines are combined, they are connected by about 34 electric wires.

All of these 34 input / output lines are processed by digital signals.

On the other hand, the control circuit on the magnetic disk device side is roughly divided as shown in FIG. 19A so as to be connected to the computer 100 and to amplify and digitize the outputs of the magnetic disk device side and various sensors. Alternatively, a digital processing circuit 101 such as a pulse motor drive circuit for positioning the magnetic head on a predetermined track is mainly configured.

The circuit 101 includes a read amplifier 102 for amplifying a signal obtained by reading information from the magnetic head, a write amplifier 103, a read / write switch 104, and an index amplifier 105 for generating one pulse signal when the magnetic disk makes one revolution. A track position detection amplifier 106 for detecting the track position of the magnetic head, a motor drive circuit 107 for rotating the magnetic disk, etc. are connected.

Reference numeral 108 is a speed control circuit for controlling the number of rotations of the motor.
A signal line 109, 110 from the digital processing circuit 101 is connected to 107, and speed control as described later is performed.

Reference numeral 111 is an amplifier for monitoring the motor rotation speed.

Reference numeral 112 denotes a television.

By the way, in the present invention based on the above-mentioned circuit configuration, high density recording can be performed in addition to the general disk rotation speed at the same rotation speed during recording and reproduction, and reliability is improved. Therefore, a structure that changes the motor rotation speed during recording and reproduction is adopted.

That is, first, when information to be recorded from the computer 100 is input to the digital processing circuit 101 as an instruction, the circuit 101 inputs a signal to the changeover switch 104 to switch the magnetic head from the reproducing mode to the recording mode. The write amplifier 103 is activated.

After commanding the low speed rotation operation to the speed control circuit 108 via the signal line 110, it is confirmed from the amplifier 111 that the signal interval and the speed control interval time match, and the low speed rotation state is established. Then, a recording signal is input from the computer 100 to record information on the magnetic disk.

On the other hand, when a reproduction command is issued from the computer side, the read / write changeover switch 104 is changed over to the read side to operate the read amplifier 102, and the signal line 1
The speed control circuit 108 is set to the high-speed mode via 09, and after confirming that the motor is in the high-speed rotation state via the amplifier 111, the reading of recording is started and the computer 10 is started.
Input 0.

When it is desired to make the number of rotations at the time of recording and reproduction the same, it is possible to perform processing by setting the reference frequency for setting the reference high-speed rotation of the speed control circuit 108 to the same frequency as the low-speed rotation. .

FIG. 19B shows the magnetic disk rotation speed of 3
The output characteristics are shown when the output of the magnetic head is measured when information is read while changing from 00 rpm to 600 rpm.

When the recording frequency f = 125 kHz and the disk rotation speed was 300 rpm, the magnetic head output was 0.8 V.
Adjust to, and use this point P as the origin to double the rotation speed to 600r
At pm, the output Q of the magnetic head was almost doubled.

Further, the recording frequency f is doubled to 250 kHz.
When the magnetic recording density is increased, the output at the point S is reduced by about 25% from the point P because the magnetic recording density is increased, and if the number of rotations is doubled in this state, the output is approximately twice the point R.
The points were obtained.

Based on this output characteristic, the magnetic disk 30
When rotating at 0 rpm and performing magnetic recording at a frequency of 250 kHz, when reproducing at that number of rotations, the S point is 0.6.
V was obtained, but as described above, when the number of revolutions was set to 600 rpm during reproduction, an output of 1.2 V at point R was obtained.

That is, since a positive output voltage of 0.6 V is obtained, even if there is a drop in output due to variations in the characteristics of the magnetic disk or a drop due to loss in the magnetic circuit of the magnetic head, it is sufficient for digital processing. It was possible to obtain a high output voltage and improve the reliability.

By the way, when the image signal of the television 112 is recorded on the magnetic disk, it is set to 1 when the magnetic disk is set to 3600 rpm when recording one screen of the cathode ray tube.
Since one field is synchronized with the track, one screen can be recorded.

One screen means one field, and
Second / 60-sheet screen = 16.7 ms.

By the way, since the frequency for recording the television image on the magnetic disk is 6.1 MHz, FIG.
As described above, the rotation speed is 3600 rpm / 300 rp
If m = 12 times, the output should increase, but the recording frequency becomes 6.1 MHz / 250 kHz = 24 times, the recording density increases, and the amplifier output becomes approximately 0.4 to 0.5 V. In order to record and reproduce the television image, it can be surely performed by rotating the disc at a high speed.

By the way, the electronic parts constituting the control circuit shown in FIG. 19 (A) have three components as shown in FIGS.
It is mounted on one board.

That is, the above-mentioned printed boards 65 and 11
3, 114.

The printed circuit board 65 is equipped with an index, track position detection, motor drive circuit and the like.

The board 113 is equipped with a read / write changeover switch for a magnetic head, a read and a write amplifier, and the board 114 is equipped with interface-related circuits for processing signals from the boards 65 and 113. I am doing it.

Further, the connectors 115 are provided on each of the boards 65 and 113, and the connector 116 coupled to these is provided on the board 114 side so that the boards can be easily connected.

As shown in FIG. 18, since each board is attached to the upper and lower surfaces and side surfaces of the chassis, adjustment and confirmation of electric signals can be easily performed from the outside of the chassis, and when any circuit fails, etc. It can be easily repaired by replacing the board.

By the way, the magnetic disk device is used as a storage device of a computer. In this case, since there are parts such as a cathode ray tube, a power transformer and a motor which generate a strong magnetic field in the periphery of the device, the device is protected from these magnetic fields. There is a need to.

Therefore, in the present invention, the chassis 1 is formed in a U shape, and the upper surface and the side surface thereof are made of iron slide frames 78,
It is covered with the slide plate 84 and the cassette guide 87 to block the external magnetic field, so that the structure has a large magnetic shield effect.

FIGS. 20A to 20D are for explaining the tracks of the magnetic disk. Although eight tracks are shown in the figure, actually 40 tracks can be recorded.

FIG. 20B shows the tracks [0 to 2] in an enlarged manner. The track width a is 50 μm, the track interval b is 70 μm, and the track pitch is a + b = 120 μm.
m.

As described above, when the track interval b is larger than the track width, if recording can be performed between the tracks, 40 tracks can be increased to 80, and the recording capacity can be doubled.

FIG. 20C shows a state in which the capacity is doubled as described above.

In FIG. 20C, a = 50 μm, b
= 10 μm, and the track pitch is a + b = 60 μm.

By the way, when the track interval is reduced in this way, magnetic recording interference occurs between adjacent tracks.

Therefore, in the present invention, as shown in FIG. 20D, a method of magnetic recording by using two azimuth heads and alternately changing the recording direction is adopted.

On the other hand, when the reproducing output was measured with the magnetic head 47 shifted from the outer circumference to the inner circumference at intervals of 10 μm with respect to the magnetic disk shown in FIG. 20D, the result was as shown in FIG. 21A.

This reproduced output voltage is obtained by measuring the output of the read amplifier 102. Finally, this reproduced output voltage is input to a digital processing circuit and shaped into a 5V peak-to-peak pulse of TTL level and used by a computer or the like. Join.

Therefore, when the output of FIG. 21 (A) is input to the digital processing circuit, the input level is set to 0.4 V and a voltage of 0.4 V or higher at the input generates a pulse. If the setting is made so that it does not occur, a normal digital signal is generated even if the amount of deviation between the center of the track and the magnetic head deviates by ± 25 μm as shown in FIG.

Therefore, the total amount of dimensional deviation is allowed up to ± 25 μm due to the deflection of the motor shaft, the error of the radius of the cam 26, and the expansion and contraction of the magnetic disk due to temperature and humidity.

On the other hand, FIG. 21B shows the output when the double-density track shown in FIG. 20C is reproduced.

In FIG. 21B, the curve A shows the output characteristics of the track [0] when the track [1] is not magnetically recorded, and the curve B is the track when the track [0] is not magnetically recorded. The characteristic which measured the output of [1] is shown.

Information is recorded on tracks [0] and [1],
When the magnetic head is moved from the track [0] direction to the track [1] direction for measurement, an output as shown by a curve C is reproduced between the curves A and B.

That is, information interference occurs.

When the voltage in the shaded area surrounded by the curves A, B and C is measured, the curves A and B are not completely summed to form the curve C, but other noise components are mixed. I understand. Therefore, the portion of the curve C is not accurate information.

In such a case, as shown in FIG. 21 (B), the amount of deviation between the track and the magnetic head is limited to about ± 12 μm, which is 1/2 that of FIG. 21 (A), and the input to the digital circuit is limited. The level would have to be set to 0.65V.

That is, in order to double the amount of information by the recording method as shown in FIG. 20C, the dimensional accuracy must be doubled or more, and high-precision and expensive parts are required.

Therefore, in the present invention, FIG.
The recording method as shown in (D) was adopted.

That is, recording was carried out by using head gaps which were oriented in different directions of θ ₁ = θ ₂ for adjacent tracks.

Note that θ ₁ = θ ₂ = 10 degrees.

The structure of such a magnetic head is shown in FIG.

In FIG. 22, reference numerals 117 and 118 denote core halves constituting one magnetic head core, and a gap G1 having an angle of θ ₁ is formed at the abutting portion of both cores.

Reference numerals 119 and 120 denote core halves constituting the other magnetic core, and a gap G2 having an angle of θ ₂ is formed at the abutting portion of the two core halves.

These cores are supported by a core support 121, and coils 122 are wound around the core halves 117 and 119.

The core support 121 is made of a resin containing a large amount of a glass material 123 that adheres between the cores or a glass material having a coefficient of expansion approximately equal to that of sendust, which is a material of the core, and is used for vibration, temperature, etc. It is designed to withstand environmental changes.

Now, after the same information is magnetically recorded on the tracks [0 to 2], the head composed of the core halves 117 and 118 of FIG. 22 is moved by 10 μm from the track outer peripheral direction to the inner peripheral direction by the reproduction output voltage. Was measured, the output characteristic of the curve A shown in FIG. 21C was obtained.

In the characteristic indicated by the curve A, the track [1]
The reason why the output voltage is small in the area is because the track [1] is recorded by the magnetic head having the inclined gap of θ ₂ .

That is, since the gap in which the track [1] is recorded is different from the gap of the head which is now passing by 20 degrees, the output is small and the noise component increases.

On the other hand, when the reproducing output is measured by moving from the track outer peripheral direction to the inner peripheral direction using the head side composed of the core halves 119 and 120, the curve B shown by the broken line in FIG.
You will get output like

At this time, the optimum reproduction output voltage is obtained at the track [1] portion.

In this way, magnetic recording and reproduction are performed by an azimuth head having a gap inclined by θ _{1 for} even-numbered tracks and a gap inclined by θ _{2 for} odd-numbered digits, thus magnetic field between adjacent tracks. Interference between recorded information is extremely reduced.

Therefore, if the input level is set to 0.4 V, the amount of deviation between the recorded track and the magnetic head is 25.
Up to μm will be allowed.

In this way, it is easier to perform high-density recording by using the magnetic head with the gap angle θ oriented in the opposite direction, the mechanical dimensional accuracy becomes easier, the design is easy by the simple mechanism, and the compatibility of the magnetic recording medium is improved. Will increase.

FIGS. 23A and 23B are diagrams for explaining another example of the structure of the magnetic head. In this embodiment, the magnetic heads 124 are separated by a predetermined distance b, and each pair of magnetic core halves are separated. 125 and 126 are arranged and attached to the head stand 127.

The thickness a of the core halves 125 and 126 is 50 μm.
m, the distance b is 2.5 mm, and each is made of sendust and is glass-welded with a gap G = 0.1 μm, and the coil 128 is attached using the winding window 129.

When a magnetic head having such a structure is used,
When recording is performed as shown in FIG. 20B, recording and reproduction of tracks [0 to 19] on the core half body 125 side and tracks [20 to 39] on the other core half body 126 are in charge. Can be made.

Therefore, when such a magnetic head 124 is used, in order to record and reproduce 40 tracks, the head base 12 can be operated by 20 steps by the pulse motor 8 to cover all the tracks.

In this case, the cam 26 may have 20 stages.

For example, in the case of a magnetic head having only one core, when calculating the time when it is desired to change to tracks [0 to 20], the speed characteristic of the pulse motor is 3 ms for one track, so 20 × 3 ms = It will be 60 ms.

Further, even when the magnetic head arrives at the twentieth track, the pulse motor 8 does not suddenly stop but slightly vibrates. Therefore, it is necessary to wait until the pulse motor 8 stops before recording and reproducing. Therefore, recording and reproduction cannot be started until after about 70 ms.

On the other hand, when the head shown in FIG. 23 is adopted, after recording / reproducing the track [0], it is possible to record / reproduce it on the track [20] immediately without waiting time.

Further, with a head having one core, [0-3
9] Track recording / playback is 3 ms × 39 + 1
While 0 (waiting time) = 127 ms is required, FIG.
In the case of the head shown in (3), 3 ms × 19 + 10 (waiting time) = 67 ms, so a difference of 60 ms occurs, and it has been found that high speed can be realized.

Next, a magnetic disk cassette applied to the magnetic disk device according to the present invention will be described.

As shown in FIG. 25, the cassette 93 is composed of upper and lower cassette halves 130 and 131, in which a magnetic disk 94 having a center hub 95 is housed.
Each cassette half has a through hole 132 into which the center hub 95 is fitted, and a head window 133 is formed therein.

Reference numeral 134 indicates an arrow for indicating the cassette mounting method, and reference numeral 135 indicates a concave portion to which a label 136 for writing a program name or the like is attached.

Reference numerals 137 and 138 are positioning holes into which the projections 7a at the upper ends of the pins 7 are fitted.

By the way, reference numeral 139 designates a shutter fitted on the outer side of the cassette halves 130, 131 which are vertically fitted together, and has a U-shaped cross section, and can be slid so as to be sandwiched from the outside of the cassette. Is fitted to.

At one end of the shutter 139, there is formed a projecting piece 141 slidably fitted in a groove 140 formed on the upper surface on the cassette half 130 side.

Further, a bent portion 142 is formed inwardly in a state of facing the projecting piece 141.

The bent portion 142 is fitted in the grooves 143 and 144 formed in the upper and lower cassette halves and guides the shutter 139.

Also, the groove 1 of the lower cassette half 131
A pin 145 is projectingly provided at the inner rear end of the spring 44, and the spring 14 is provided between the pin 145 and the bent portion 142.
6 is stretched and gives a force to draw the shutter 139 toward the center of the cassette half.

It should be noted that lower stepped parts 147 for guiding the bent parts 142 are formed along the side edges of the grooves 143, 144 of the cassette halves 130, 131, respectively.

A quadrilateral recess 148 with which the shutter 139 is in contact is formed on the outer surface of each cassette half 130, 131.

Reference numeral 149 is a shutter stopper.

Also, the reference numeral 150 indicates the cassette guide 87 when the cassette is inserted into the cassette guide 87.
It is a groove through which a bent portion 87d for opening a shutter projecting at the entrance end of is opened when the cassette is inserted.

As shown in FIG. 28, this bent portion 87d contacts the edge 139a of the shutter 139 when the cassette is mounted, and opens the shutter 139 with the head window 133 closed.

FIG. 26 shows the state in which the shutter is closed.
As shown in FIGS. 26A and 26B, the opened state is shown in FIGS.
It shows in (D).

Since the magnetic disk cassette used in the magnetic disk apparatus according to the present invention is constructed as described above, it is possible to automatically open the shutter which is always closed simply by inserting it in the cassette guide on the apparatus side. Therefore, magnetic recording and reproduction can be surely performed.

[0235]

As described above, according to the disk device of the present invention, the bottom plate and the both side plates are formed by bending the flat chassis into the substantially U shape on both sides thereof, and the front end portion is opened. The main chassis is formed as an end, and a holding member capable of holding a cassette containing a disk-shaped recording medium inserted from an open end of the main chassis is provided, and the bottom plate includes the disk-shaped recording medium. A disk mounting section for mounting the disk, a disk rotation drive section for rotating the disk-shaped recording medium mounted in the disk mounting section, and a disk-shaped recording medium mounted in the disk mounting section for recording or reproducing. Head means and head moving means for moving the head means in the radial direction of the disk-shaped recording medium are arranged, and the both side plates are provided on the both side plates. By engaging the engaging portion formed on the side surface of the holding member and moving the holding member only in the direction substantially perpendicular to the cassette insertion direction, the disc mounting portion is moved from the attachment / detachment position separated from the disc mounting portion. A configuration is adopted in which a plurality of guide portions for transferring the holding member to the mounting position to be mounted on, or vice versa are formed.

According to this structure, since the side plate having the guide portion can be directly formed on the bottom plate without providing the side plate mounting portion on the bottom plate of the chassis, the length in the device width direction can be reduced. The size of the device can be reduced, and the position of the guide part formed on the side plate can be easily specified with respect to the bottom plate provided with the disc-shaped recording medium insertion port and the disc mounting part. it can.

Also, in the bent portion (side plate) of the chassis,
By forming the guide part of the holding member in advance during molding of the chassis, it is possible to realize the support and guide means of the holding member with a simple configuration, and the assembling workability is also achieved by using a separate member for the holding member support mechanism. It is dramatically improved as compared with the one that is attached with screws.

Further, since the guide portion is formed on the side plate so as to move the holding member only in the direction substantially perpendicular to the cassette inserting direction, it is not necessary to provide the side plate with the guide portion for moving the holding member in the cassette inserting direction. Therefore, the length of the side plate in the cassette insertion direction can be shortened. This also leads to a reduction in the length of the entire device in the cassette insertion direction. Further, since it is sufficient to secure the movement accuracy of the holding member in one direction, the side plate bending step is facilitated.

Further, by forming the guide portion for transferring the holding member in the side plate as an I-shaped guide groove having an open upper end, the guide portion can be easily formed on the side plate and the holding member It facilitates the process of engaging the guide portion.

Further, since the guide member for supporting the carriage in which the head means is arranged is configured to be supported on the bottom plate by the support piece formed by cutting and raising a part of the bottom plate, It is possible to obtain the excellent effect of reducing the size and promoting miniaturization of the device.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a disk and a head drive mechanism of a disk device according to an embodiment of the present invention.

FIG. 2 is a perspective view of the chassis in which the head drive mechanism of the same device is mounted.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

5A is a cross-sectional view showing one bearing structure of the head base, FIG. 5B is a cross-sectional view showing another example of the bearing structure, and FIG. 5C is a cross-sectional view showing the other bearing structure of the head base. , (D) are sectional views taken along line CC of (C).

FIG. 6 is an explanatory diagram showing the structure of a cam and the structure and operation of a track outermost position detection mechanism.

FIG. 7 is an explanatory diagram showing a structure of a cam and a structure and an operation of a track outermost position detecting mechanism.

FIG. 8 is an exploded perspective view of a cassette mounting mechanism.

FIG. 9 is a perspective view of the cassette mounting mechanism in an assembled state.

FIG. 10 is a sectional view of the cassette mounting mechanism immediately after the cassette is inserted.

FIG. 11 is a sectional view of the cassette mounting mechanism in a completely mounted state.

FIG. 12 is an explanatory diagram showing the operation of the rollers during the cassette mounting operation.

FIG. 13 is a cross-sectional view of the cassette mounting mechanism before the cassette is lowered.

FIG. 14 is a sectional view of the cassette mounting mechanism after the cassette is lowered.

FIG. 15 is a perspective view showing the relationship between the cassette mounting mechanism and the chassis.

FIG. 16 is a perspective view of the chassis with a cassette mounting mechanism attached.

FIG. 17 is an explanatory diagram showing an arrangement of substrates on which a control circuit is mounted.

FIG. 18 is a side view of the chassis with a board attached.

FIG. 19A is a block diagram of a control circuit, and FIG. 19B is a diagram showing a relationship between the rotation speed of a medium and a reproduction output.

FIG. 20A is an explanatory diagram of tracks on a magnetic disk,
(B) is an explanatory view of a roughly recorded track, (C) is an explanatory view of a densely recorded track, and (D) is an explanatory view of a recording method adopted by the present invention.

21A to 21C are diagrams showing reproduction output characteristics respectively corresponding to the recording states shown in FIGS. 20B to 20D.

22A is a plan view of the magnetic head, and FIG. 22B is a sectional view taken along line DD of FIG.

23A is a plan view showing another structural example of the magnetic head, and FIG. 23B is a sectional view taken along line EE of FIG.

24A and 24B are a cross-sectional view and an explanatory view for explaining details of the track positioning mechanism.

FIG. 25 is an exploded perspective view of a magnetic disk cassette.

26 (A) and 26 (B) are a plan view and a side view of the cassette with the shutter closed, and FIGS. 26 (C) and (D) are a plan view and a side view with the shutter open.

FIG. 27 is an enlarged cross-sectional view taken along line FF of FIG.

FIG. 28 is a perspective view illustrating the opening operation of the shutter.

[Explanation of symbols]

 1 Chassis 20 Rotating Shaft 65 Printed Circuit Board 65a Coil 68 Yoke 69 Gear 73 Magnetic Sensor

Claims (3)

[Claims] 1. A bottom plate and both side plates are formed by bending a flat chassis on both sides thereof into a substantially U shape, and a front chassis is formed as an open end to form a main chassis. A holding member capable of holding a cassette containing a disk-shaped recording medium inserted from the open end is provided, and the bottom plate includes a disk mounting portion for mounting the disk-shaped recording medium and a mounting portion for the disk mounting portion. A disk rotation drive unit for rotating the disk-shaped recording medium, a head unit for recording or reproducing on the disk-shaped recording medium mounted on the disk mounting unit, and the head unit for the disk-shaped recording medium. Head moving means for moving in the radial direction is arranged, and the both side plates are engaged with an engaging portion formed on a side surface of the holding member. However, by moving this holding member only in a direction substantially perpendicular to the cassette insertion direction, the holding member is moved from the attachment / detachment position separated from the disc attachment portion to the attachment position for attachment to the disc attachment portion, or vice versa. A disk device, wherein a plurality of guide portions for transferring are formed. 2. The disk device according to claim 1, wherein the guide portion is formed in the side plate as an I-shaped guide groove having an open upper end. 3. The head moving means comprises a carriage on which the head means is arranged, and a guide member for movably supporting the carriage in the radial direction of the disk-shaped recording medium. 3. The disk device according to claim 1, wherein the disk device is supported by the bottom plate by a support piece formed by cutting and raising a part of the bottom plate.